Urologic Solution G

Citric Acid:

• Description
• Action
• Indications
• Contraindications
• Precautions
• Adverse reactions
• Dosage and administration
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• Urologic Solution G (Citric Acid) reviews

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DESCRIPTION

The product is a clear, colorless solution containing Urologic Solution G (Citric Acid) Acid USP 640 mg/5 mL, and Hydrous Sodium Citrate USP 490 mg/5 mL. It also contains Methylparaben NF and Propylparaben NF as preservatives. These concentrations yield 1 mEq of sodium, equivalent to 1 mEq of bicarbonate per mL of solution.

ACTION

Oral citrate solution is used as a systemic and urinary alkalinizer. Less than 5% of the citrate is excreted in the urine unchanged, since citrate oxidation is to a great extent complete.

INDICATIONS

Urologic Solution G (Citric Acid)^® is indicated for the treatment of metabolic acidosis. This solution is also useful in conditions where long term maintenance of alkaline urine is needed (e.g. uric acid and cystine calculi of the urinary tract). Urologic Solution G (Citric Acid)^® is also effective in treatment for acidosis of certain renal tubular disorders.

CONTRAINDICATIONS

Urologic Solution G (Citric Acid)^® is contraindicated in patients with severe renal impairment, oliguria or azotemia, untreated Addison's disease, adynamia episodica hereditaria, acute dehydration, heat cramp, anuria, severe myocardial damage, and hyperkalemia.

PRECAUTIONS

The citrate solution should be used with caution in patients with impaired renal function to avoid hypernatremia or alkalosis in the presence of hypocalcemia. Periodic determinations of serum electrolyte levels (especially bicarbonate levels) should be done in patients with renal disease to avoid cardiac failure, hypertension, peripheral and pulmonary edema, and toxemia of pregnancy. The solution should be diluted with water and preferably taken after meals to avoid saline laxative effects.

ADVERSE REACTIONS

Citrate solution is generally well tolerated when given in recommended doses when the patient has normal renal functions.

DOSAGE AND ADMINISTRATION

The dose of Urologic Solution G (Citric Acid)^® is 10 to 30 mL, diluted with water, after meals and at bedtime. The dose should be titrated to achieve desired effects.

HOW SUPPLIED

Urologic Solution G ^® is supplied in 500 mL bottles (NDC 46287-014-01), 30 mL unit dose bottles, 10 bottles per carton (NDC 46287-014-30), and 15 mL unit dose bottles, 10 bottles per carton (NDC 46287-014-15).

PHARMACIST

Dispense in well-closed containers.

Store at 20°-25°C (68°-77°F); excursions permitted to 15°-30°C (59°-86°F)..

CMP Pharma, Inc.

Post Office Box 147

Farmville, North Carolina 27828

Revised July 2015

Copyright ^© CMP Pharma, Inc. 2015

NDC 46287-014-01

500 mL

Urologic Solution G (Citric Acid)^®

ORAL CITRATE (SHOHL'S) SOLUTION

CONTAINS: Hydrous Sodium Citrate USP 490 mg/5 mL;

Urologic Solution G (Citric Acid) Acid USP 640 mg/5 mL; Methylparaben NF;

Propylparaben NF; Alcohol USP 0.25%.

USUAL

Dosage: See package insert.

Dispense in a well-closed container.

Store at 20°-25°C (68°-77°F); excursions permitted

to 15°-30°C (59°-86°F). [See USP Controlled Room

Temperature].

Rx Only

LOT:

EXP:

CMP

PHARMA

Farmville, NC 27828

Magnesium Oxide:

• Description
• Clinical pharmacology
• Indications and usage
• Contraindications
• Warnings
• Precautions
• Adverse reactions
• Overdosage
• Dosage and administration
• How supplied
• References
• Urologic Solution G (Magnesium Oxide) reviews

Urologic Solution G (Magnesium Oxide) Sulfate

Injection, USP

Ansyr Plastic Syringe

Rx only

Hospira Logo

DESCRIPTION

Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP is a sterile solution of Urologic Solution G (Magnesium Oxide) sulfate heptahydrate in Water for Injection, USP administered by the intravenous or intramuscular routes as an electrolyte replenisher or anticonvulsant. Must be diluted before intravenous use. May contain sulfuric acid and/or sodium hydroxide for pH adjustment. The pH is 5.5 to 7.0. The 50% concentration has an osmolarity of 4.06 mOsmol/mL (calc.).

The solution contains no bacteriostat, antimicrobial agent or added buffer (except for pH adjustment) and is intended only for use as a single-dose injection. When smaller doses are required the unused portion should be discarded with the entire unit.

Urologic Solution G (Magnesium Oxide) Sulfate, USP heptahydrate is chemically designated MgSO₄ - 7H₂O with molecular weight of 246.48 and occurs as colorless crystals or white powder freely soluble in water.

The plastic syringe is molded from a specially formulated polypropylene. Water permeates from inside the container at an extremely slow rate which will have an insignificant effect on solution concentration over the expected shelf life. Solutions in contact with the plastic container may leach out certain chemical components from the plastic in very small amounts; however, biological testing was supportive of the safety of the syringe material.

CLINICAL PHARMACOLOGY

Urologic Solution G (Magnesium Oxide) (Mg⁺⁺) is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability.

As a nutritional adjunct in hyperalimentation, the precise mechanism of action for Urologic Solution G (Magnesium Oxide) is uncertain. Early symptoms of hypomagnesemia (less than 1.5 mEq/liter) may develop as early as three to four days or within weeks.

Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors. Hypocalcemia and hypokalemia often follow low serum levels of Urologic Solution G (Magnesium Oxide). While there are large stores of Urologic Solution G (Magnesium Oxide) present intracellularly and in the bones of adults, these stores often are not mobilized sufficiently to maintain plasma levels. Parenteral Urologic Solution G (Magnesium Oxide) therapy repairs the plasma deficit and causes deficiency symptoms and signs to cease.

Urologic Solution G (Magnesium Oxide) prevents or controls convulsions by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse. Urologic Solution G (Magnesium Oxide) is said to have a depressant effect on the central nervous system (CNS), but it does not adversely affect the woman, fetus or neonate when used as directed in eclampsia or pre-eclampsia. Normal plasma Urologic Solution G (Magnesium Oxide) levels range from 1.5 to 2.5 mEq/liter.

As plasma Urologic Solution G (Magnesium Oxide) rises above 4 mEq/liter, the deep tendon reflexes are first decreased and then disappear as the plasma level approaches 10 mEq/liter. At this level respiratory paralysis may occur. Heart block also may occur at this or lower plasma levels of Urologic Solution G (Magnesium Oxide). Serum Urologic Solution G (Magnesium Oxide) concentrations in excess of 12 mEq/L may be fatal.

Urologic Solution G (Magnesium Oxide) acts peripherally to produce vasodilation. With low doses only flushing and sweating occur, but larger doses cause lowering of blood pressure. The central and peripheral effects of Urologic Solution G (Magnesium Oxide) poisoning are antagonized to some extent by intravenous administration of calcium.

Pharmacokinetics

With intravenous administration the onset of anticonvulsant action is immediate and lasts about 30 minutes. Following intramuscular administration the onset of action occurs in about one hour and persists for three to four hours. Effective anticonvulsant serum levels range from 2.5 to 7.5 mEq/liter. Urologic Solution G (Magnesium Oxide) is excreted solely by the kidneys at a rate proportional to the plasma concentration and glomerular filtration.

INDICATIONS AND USAGE

Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP is suitable for replacement therapy in Urologic Solution G (Magnesium Oxide) deficiency, especially in acute hypomagnesemia accompanied by signs of tetany similar to those observed in hypocalcemia. In such cases, the serum Urologic Solution G (Magnesium Oxide) (Mg⁺⁺) level is usually below the lower limit of normal (1.5 to 2.5 mEq/liter) and the serum calcium (Ca⁺⁺) level is normal (4.3 to 5.3 mEq/liter) or elevated.

In total parenteral nutrition (TPN), Urologic Solution G (Magnesium Oxide) sulfate may be added to the nutrient admixture to correct or prevent hypomagnesemia which can arise during the course of therapy.

Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP is also indicated for the prevention and control of seizures (convulsions) in pre-eclampsia and eclampsia, respectively.

CONTRAINDICATIONS

Parenteral administration of the drug is contraindicated in patients with heart block or myocardial damage.

WARNINGS

FETAL HARM: Continuous administration of Urologic Solution G (Magnesium Oxide) sulfate beyond 5 to 7 days to pregnant women can lead to hypocalcemia and bone abnormalities in the developing fetus. These bone abnormalities include skeletal demineralization and osteopenia. In addition, cases of neonatal fracture have been reported. The shortest duration of treatment that can lead to fetal harm is not known. Urologic Solution G (Magnesium Oxide) sulfate should be used during pregnancy only if clearly needed. If Urologic Solution G (Magnesium Oxide) sulfate is given for treatment of preterm labor, the woman should be informed that the efficacy and safety of such use have not been established and that use of Urologic Solution G (Magnesium Oxide) sulfate beyond 5 to 7 days may cause fetal abnormalities.

ALUMINUM TOXICITY: This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.

Research indicates that patients with impaired kidney function, including premature neonates, who receive parenteral levels of aluminum at greater than 4 to 5 mcg/kg/day accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration.

Parenteral use in the presence of renal insufficiency may lead to Urologic Solution G (Magnesium Oxide) intoxication. Intravenous use in the eclampsia should be reserved for immediate control of life-threatening convulsions.

PRECAUTIONS

General

Administer with caution if flushing and sweating occurs. When barbiturates, narcotics or other hypnotics (or systemic anesthetics) are to be given in conjunction with Urologic Solution G (Magnesium Oxide), their dosage should be adjusted with caution because of additive CNS depressant effects of Urologic Solution G (Magnesium Oxide).

Because Urologic Solution G (Magnesium Oxide) is removed from the body solely by the kidneys, the drug should be used with caution in patients with renal impairment. Urine output should be maintained at a level of 100 mL or more during the four hours preceding each dose. Monitoring serum Urologic Solution G (Magnesium Oxide) levels and the patient's clinical status is essential to avoid the consequences of overdosage in toxemia. Clinical indications of a safe dosage regimen include the presence of the patellar reflex (knee jerk) and absence of respiratory depression (approximately 16 breaths or more/minute). When repeated doses of the drug are given parenterally, knee jerk reflexes should be tested before each dose and if they are absent, no additional Urologic Solution G (Magnesium Oxide) should be given until they return. Serum Urologic Solution G (Magnesium Oxide) levels usually sufficient to control convulsions range from 3 to 6 mg/100 mL (2.5 to 5 mEq/liter). The strength of the deep tendon reflexes begins to diminish when Urologic Solution G (Magnesium Oxide) levels exceed 4 mEq/liter. Reflexes may be absent at 10 mEq magnesium/liter, where respiratory paralysis is a potential hazard. An injectable calcium salt should be immediately available to counteract the potential hazards of Urologic Solution G (Magnesium Oxide) intoxication in eclampsia.

50% Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP must be diluted to a concentration of 20% or less prior to intravenous infusion. Rate of administration should be slow and cautious, to avoid producing hypermagnesemia. The 50% solution also should be diluted to 20% or less for intramuscular injection in infants and children.

Laboratory Tests

Urologic Solution G (Magnesium Oxide) sulfate injection should not be given unless hypomagnesemia has been confirmed and the serum concentration of Urologic Solution G (Magnesium Oxide) is monitored. The normal serum level is 1.5 to 2.5 mEq/L.

Drug Interactions

CNS Depressants - When barbiturates, narcotics or other hypnotics (or systemic anesthetics), or other CNS depressants are to be given in conjunction with Urologic Solution G (Magnesium Oxide), their dosage should be adjusted with caution because of additive CNS depressant effects of Urologic Solution G (Magnesium Oxide). CNS depression and peripheral transmission defects produced by Urologic Solution G (Magnesium Oxide) may be antagonized by calcium.

Neuromuscular Blocking Agents - Excessive neuromuscular block has occurred in patients receiving parenteral Urologic Solution G (Magnesium Oxide) sulfate and a neuromuscular blocking agent; these drugs should be administered concomitantly with caution.

Cardiac Glycosides - Urologic Solution G (Magnesium Oxide) sulfate should be administered with extreme caution in digitalized patients, because serious changes in cardiac conduction which can result in heart block may occur if administration of calcium is required to treat Urologic Solution G (Magnesium Oxide) toxicity.

Pregnancy

Teratogenic Effects

Pregnancy Category D (See WARNINGS and PRECAUTIONS )

See WARNINGS and PRECAUTIONS .

Urologic Solution G (Magnesium Oxide) sulfate can cause fetal abnormalities when administered beyond 5 to 7 days to pregnant women. There are retrospective epidemiological studies and case reports documenting fetal abnormalities such as hypocalcemia, skeletal demineralization, osteopenia and other skeletal abnormalities with continuous maternal administration of Urologic Solution G (Magnesium Oxide) sulfate for more than 5 to 7 days.^1-10 Urologic Solution G (Magnesium Oxide) sulfate injection should be used during pregnancy only if clearly needed. If this drug is used during pregnancy, the woman should be apprised of the potential harm to the fetus.

Nonteratogenic Effects

When administered by continuous intravenous infusion (especially for more than 24 hours preceding delivery) to control convulsions in a toxemic woman, the newborn may show signs of Urologic Solution G (Magnesium Oxide) toxicity, including neuromuscular or respiratory depression (See OVERDOSAGE ).

Labor and Delivery

Continuous administration of Urologic Solution G (Magnesium Oxide) sulfate is an unapproved treatment for preterm labor. The safety and efficacy of such use have not been established. The administration of Urologic Solution G (Magnesium Oxide) sulfate outside of its approved indication in pregnant women should be by trained obstetrical personnel in a hospital setting with appropriate obstetrical care facilities.

Nursing Mothers

Since Urologic Solution G (Magnesium Oxide) is distributed into milk during parenteral Urologic Solution G (Magnesium Oxide) sulfate administration, the drug should be used with caution in nursing women.

Geriatrics

Geriatric patients often require reduced dosage because of impaired renal function. In patients with severe impairment, dosage should not exceed 20 grams in 48 hours. Serum Urologic Solution G (Magnesium Oxide) should be monitored in such patients.

ADVERSE REACTIONS

The adverse effects of parenterally administered Urologic Solution G (Magnesium Oxide) usually are the result of Urologic Solution G (Magnesium Oxide) intoxication. These include flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis. Hypocalcemia with signs of tetany secondary to Urologic Solution G (Magnesium Oxide) sulfate therapy for eclampsia has been reported.

OVERDOSAGE

Urologic Solution G (Magnesium Oxide) intoxication is manifested by a sharp drop in blood pressure and respiratory paralysis. Disappearance of the patellar reflex is a useful clinical sign to detect the onset of Urologic Solution G (Magnesium Oxide) intoxication. In the event of overdosage, artificial ventilation must be provided until a calcium salt can be injected intravenously to antagonize the effects of Urologic Solution G (Magnesium Oxide).

For Treatment of Overdose

Artificial respiration is often required. Intravenous calcium, 10 to 20 mL of a 5% solution (diluted if desirable with isotonic sodium chloride for injection) is used to counteract effects of hypermagnesemia. Subcutaneous physostigmine, 0.5 to 1 mg may be helpful.

Hypermagnesemia in the newborn may require resuscitation and assisted ventilation via endotracheal intubation or intermittent positive pressure ventilation as well as intravenous calcium.

DOSAGE AND ADMINISTRATION

Dosage of Urologic Solution G (Magnesium Oxide) sulfate must be carefully adjusted according to individual requirements and response, and administration of the drug should be discontinued as soon as the desired effect is obtained.

Both intravenous and intramuscular administration are appropriate. Intramuscular administration of the undiluted 50% solution results in therapeutic plasma levels in 60 minutes, whereas intravenous doses will provide a therapeutic level almost immediately. The rate of intravenous injection should generally not exceed 150 mg/minute (1.5 mL of a 10% concentration or its equivalent), except in severe eclampsia with seizures. Continuous maternal administration of Urologic Solution G (Magnesium Oxide) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Solutions for intravenous infusion must be diluted to a concentration of 20% or less prior to administration. The diluents commonly used are 5% Dextrose Injection, USP and 0.9% Sodium Chloride Injection, USP. Deep intramuscular injection of the undiluted (50%) solution is appropriate for adults, but the solution should be diluted to a 20% or less concentration prior to such injection in children.

In Urologic Solution G (Magnesium Oxide) Deficiency

In the treatment of mild Urologic Solution G (Magnesium Oxide) deficiency, the usual adult dose is 1 gram, equivalent to 8.12 mEq of Urologic Solution G (Magnesium Oxide) (2 mL of the 50% solution) injected intramuscularly every six hours for four doses (equivalent to a total of 32.5 mEq of Urologic Solution G (Magnesium Oxide) per 24 hours). For severe hypomagnesemia, as much as 250 mg (approximately 2 mEq) per kg of body weight (0.5 mL of the 50% solution) may be given intramuscularly within a period of four hours if necessary. Alternatively, 5 grams, (approximately 40 mEq) can be added to one liter of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP for slow intravenous infusion over a three-hour period. In the treatment of deficiency states, caution must be observed to prevent exceeding the renal excretory capacity.

In Hyperalimentation

In total parenteral nutrition, maintenance requirements for Urologic Solution G (Magnesium Oxide) are not precisely known. The maintenance dose used in adults ranges from 8 to 24 mEq (1 gram to 3 grams) daily; for infants, the range is 2 to 10 mEq (0.25 gram to 1.25 grams) daily.

In Pre-eclampsia or Eclampsia

In severe pre-eclampsia or eclampsia, the total initial dose is 10 grams to 14 grams of Urologic Solution G (Magnesium Oxide) sulfate. Intravenously, a dose of 4 grams to 5 grams in 250 mL of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP may be infused. Simultaneously, intramuscular doses of up to 10 grams (5 grams or 10 mL of the undiluted 50% solution in each buttock) are given. Alternatively, the initial intravenous dose of 4 grams may be given by diluting the 50% solution to a 10 or 20% concentration; the diluted fluid (40 mL of a 10% solution or 20 mL of a 20% solution) may then be injected intravenously over a period of three to four minutes. Subsequently, 4 grams to 5 grams (8 to 10 mL of the 50% solution) are injected intramuscularly into alternate buttocks every four hours as needed, depending on the continuing presence of the patellar reflex and adequate respiratory function. Alternatively, after the initial intravenous dose, some clinicians administer 1 gram to 2 grams/hour by constant intravenous infusion. Therapy should continue until paroxysms cease. A serum Urologic Solution G (Magnesium Oxide) level of 6 mg/100 mL is considered optimal for control of seizures. A total daily (24 hr) dose of 30 grams to 40 grams should not be exceeded. In the presence of severe renal insufficiency, the maximum dosage of Urologic Solution G (Magnesium Oxide) sulfate is 20 grams/48 hours and frequent serum Urologic Solution G (Magnesium Oxide) concentrations must be obtained. Continuous use of Urologic Solution G (Magnesium Oxide) sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Other Uses

In counteracting the muscle-stimulating effects of barium poisoning, the usual dose of Urologic Solution G (Magnesium Oxide) sulfate is 1 gram to 2 grams given intravenously.

For controlling seizures associated with epilepsy, glomerulonephritis or hypothyroidism, the usual adult dose is 1 gram administered intramuscularly or intravenously.

In paroxysmal atrial tachycardia, Urologic Solution G (Magnesium Oxide) should be used only if simpler measures have failed and there is no evidence of myocardial damage. The usual dose is 3 grams to 4 grams (30 to 40 mL of a 10% solution) administered intravenously over 30 seconds with extreme caution.

For reduction of cerebral edema, 2.5 grams (25 mL of a 10% solution) is given intravenously.

Incompatibilities

Urologic Solution G (Magnesium Oxide) sulfate in solution may result in a precipitate formation when mixed with solutions containing:

Alcohol (in high Heavy Metals

concentrations) Hydrocortisone sodium

Alkali carbonates and succinate

bicarbonates Phosphates

Alkali hydroxides Polymixin B sulfate

Arsenates Procaine hydrochloride

Barium Salicylates

Calcium Strontium

Clindamycin phosphate Tartrates

The potential incompatibility will often be influenced by the changes in the concentration of reactants and the pH of the solutions.

It has been reported that Urologic Solution G (Magnesium Oxide) may reduce the antibiotic activity of streptomycin, tetracycline and tobramycin when given together.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

HOW SUPPLIED

Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP is supplied in single-dose containers as follows:

Do not administer unless solution is clear and container is undamaged. Discard unused portion.

Store at 20 to 25°C (68 to 77°F).

REFERENCES

• Yokoyama K, Takahashi N, Yada Y. Prolonged maternal Urologic Solution G (Magnesium Oxide) administration and bone metabolism in neonates. Early Hum Dev. 2010;86(3):187-91. Epub 2010 Mar 12.
• Wedig KE, Kogan J, Schorry EK et al. Skeletal demineralization and fractures caused by fetal Urologic Solution G (Magnesium Oxide) toxicity. J. Perinatol. 2006; 26(6):371-4.
• Nassar AH, Sakhel K, Maarouf H, et al. Adverse maternal and neonatal outcome of prolonged course of Urologic Solution G (Magnesium Oxide) sulfate tocolysis. Acta Obstet Gynecol Scan. 2006;85(9):1099-103.
• Malaeb SN, Rassi A, Haddad MC. Bone mineralization in newborns whose mothers received Urologic Solution G (Magnesium Oxide) sulphate for tocolysis of premature labor. Pediatr Radiol. 2004;34(5):384-6. Epub 2004 Feb 18.
• Matsuda Y, Maeda Y, Ito M, et al. Effect of Urologic Solution G (Magnesium Oxide) sulfate treatment on neonatal bone abnormalities. Gynecol Obstet Invest. 1997;44(2):82-8.
• Schanler RJ, Smith LG, Burns PA. Effects of long-term maternal intravenous Urologic Solution G (Magnesium Oxide) sulfate therapy on neonatal calcium metabolism and bone mineral content. Gynecol Obstet Invest. 1997;43(4):236-41.
• Santi MD, Henry GW, Douglas GL. Urologic Solution G (Magnesium Oxide) sulfate treatment of preterm labor as a cause of abnormal neonatal bone mineralization. J Pediatr Orthrop. 1994;14(2):249-53.
• Holcomb WL, Shackelford GD, Petrie RH. Urologic Solution G (Magnesium Oxide) tocolysis and neonatal bone abnormalities; a controlled study. Obstet Gynecol. 1991; 78(4):611-4.
• Cumming WA, Thomas VJ. Hypermagnesemia: a cause of abnormal metaphyses in the neonate. Am J Roentgenol. 1989; 152(5):1071-2.
• Lamm CL, Norton KL, Murphy RJ. Congenital rickets associated with Urologic Solution G (Magnesium Oxide) sulfate infusion for tocolysis. J Pediatr. 1988; 113(6):1078-82.
• McGuinness GA, Weinstein MM, Cruikshank DP, et al. Effects of Urologic Solution G (Magnesium Oxide) sulfate treatment on perinatal calcium metabolism. II. Neonatal responses. Obstet Gynecol. 1980; 56(5): 595-600.
• Riaz M, Porat R, Brodsky NL, et al. The effects of maternal Urologic Solution G (Magnesium Oxide) sulfate treatment on newborns: a prospective controlled study. J. Perinatol. 1998;18(6 pt 1):449-54.

Hospira, Inc., Lake Forest, IL 60045 USA

LAB-1024-1.0

April 2017

Hospira Logo

50% Urologic Solution G (Magnesium Oxide) Sulfate 5 g/10 mL (500 mg/mL)

Rx only

NDC 0409-1754-10

10 mL Single-dose syringe

50% Urologic Solution G (Magnesium Oxide) Sulfate Injection, USP

5 g/10 mL (500 mg/mL) (4 mEq Mg++/mL)

MUST BE DILUTED FOR INTRAVENOUS USE.

For Intravenous or Intramuscular Use. Sterile. 4.06 mOsmol/mL (calc.).

Contains no more than 75 mcg/L of aluminum.

Hospira, Inc., Lake Forest, IL 60045 USA

Hospira

RL-6891

Sodium Carbonate Anhydrous:

• Indications and usage
• Dosage and administration
• Dosage forms and strengths
• Contraindications
• Warnings and precautions
• Adverse reactions
• Drug interactions
• Use in specific populations
• Overdosage
• Description
• Clinical pharmacology
• Nonclinical toxicology
• Clinical studies
• How supplied/storage and handling
• Patient counseling information
• Urologic Solution G (Sodium Carbonate Anhydrous) reviews

1 INDICATIONS AND USAGE

Urologic Solution G nitrite is indicated for sequential use with Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate for treatment of acute cyanide poisoning that is judged to be life-threatening. (1)

• Use with caution if the diagnosis of cyanide poisoning is uncertain. (1)

1.1 Indication

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection is indicated for sequential use with Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate for the treatment of acute cyanide poisoning that is judged to be life-threatening. When the diagnosis of cyanide poisoning is uncertain, the potentially life-threatening risks associated with Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection should be carefully weighed against the potential benefits, especially if the patient is not in extremis.

1.2 Identifying Patients with Cyanide Poisoning

Cyanide poisoning may result from inhalation, ingestion, or dermal exposure to various cyanide-containing compounds, including smoke from closed-space fires. Sources of cyanide poisoning include hydrogen cyanide and its salts, cyanogenic plants, aliphatic nitriles, and prolonged exposure to Urologic Solution G nitroprusside.

The presence and extent of cyanide poisoning are often initially unknown. There is no widely available, rapid, confirmatory cyanide blood test. Treatment decisions must be made on the basis of clinical history and signs and symptoms of cyanide intoxication. If clinical suspicion of cyanide poisoning is high, Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection and Urologic Solution G (Sodium Carbonate Anhydrous) Thiosulfate Injection should be administered without delay.

In some settings, panic symptoms including tachypnea and vomiting may mimic early cyanide poisoning signs. The presence of altered mental status (e.g., confusion and disorientation) and/or mydriasis is suggestive of true cyanide poisoning although these signs can occur with other toxic exposures as well.

The expert advice of a regional poison control center may be obtained by calling 1-800-222-1222.

Smoke Inhalation

Not all smoke inhalation victims will have cyanide poisoning and may present with burns, trauma, and exposure to other toxic substances making a diagnosis of cyanide poisoning particularly difficult. Prior to administration of Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection, smoke-inhalation victims should be assessed for the following:

• Exposure to fire or smoke in an enclosed area
• Presence of soot around the mouth, nose, or oropharynx
• Altered mental status

Although hypotension is highly suggestive of cyanide poisoning, it is only present in a small percentage of cyanide-poisoned smoke inhalation victims. Also indicative of cyanide poisoning is a plasma lactate concentration greater than or equal to 10 mmol/L (a value higher than that typically listed in the table of signs and symptoms of isolated cyanide poisoning because carbon monoxide associated with smoke inhalation also contributes to lactic acidemia). If cyanide poisoning is suspected, treatment should not be delayed to obtain a plasma lactate concentration.

1.3 Use with Other Cyanide Antidotes

Caution should be exercised when administering cyanide antidotes, other than Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate, simultaneously with Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection, as the safety of co-administration has not been established. If a decision is made to administer another cyanide antidote, other than Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate, with Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection, these drugs should not be administered concurrently in the same IV line. [see Dosage and Administration (2.2) ]

2 DOSAGE AND ADMINISTRATION

Redosing: If signs of cyanide poisoning reappear, repeat treatment using one-half the original dose of both Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate.

Monitoring: Blood pressure must be monitored during treatment. (2.2)

2.1 Administration Recommendation

Comprehensive treatment of acute cyanide intoxication requires support of vital functions. Administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite, followed by Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate, should be considered adjunctive to appropriate supportive therapies. Airway, ventilatory and circulatory support, and oxygen administration should not be delayed to administer Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate.

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate injection are administered by slow intravenous injection. They should be given as early as possible after a diagnosis of acute life-threatening cyanide poisoning has been established. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be administered first, followed immediately by Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate. Blood pressure must be monitored during infusion in both adults and children. The rate of infusion should be decreased if significant hypotension is noted.

NOTE: If signs of poisoning reappear, repeat treatment using one-half the original dose of both Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate.

In adult and pediatric patients with known anemia, it is recommended that the dosage of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be reduced proportionately to the hemoglobin concentration.

All parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

2.2 Recommended Monitoring

Patients should be monitored for at least 24-48 hours after Urologic Solution G Nitrite Injection administration for adequacy of oxygenation and perfusion and for recurrent signs and symptoms of cyanide toxicity. When possible, hemoglobin/hematocrit should be obtained when treatment is initiated. Measurements of oxygen saturation using standard pulse oximetry and calculated oxygen saturation values based on measured PO₂ are unreliable in the presence of methemoglobinemia.

Methemoglobin level: Administrations of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite solely to achieve an arbitrary level of methemoglobinemia may be unnecessary and potentially hazardous. The therapeutic effects of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite do not appear to be mediated by methemoglobin formation alone and clinical responses to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administration have been reported in association with methemoglobin levels of less than 10%. Administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite beyond the initial dose should be guided primarily by clinical response to treatment (i.e., a second dose should be considered only if there is inadequate clinical response to the first dose). It is generally recommended that methemoglobin concentrations be closely monitored and kept below 30%. Serum methemoglobin levels should be monitored during treatment using co-oximetry, and administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should generally be discontinued when methemoglobin levels exceed 30%. Intravenous methylene blue and exchange transfusion have been reported in the literature as treatments for life-threatening methemoglobinemia.

2.3 Incompatibility Information

Chemical incompatibility has been reported between Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and hydroxocobalamin and these drugs should not be administered simultaneously through the same IV line. No chemical incompatibility has been reported between Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate and Urologic Solution G (Sodium Carbonate Anhydrous) nitrite, when administered sequentially through the same IV line as described in Dosage and Administration.

3 DOSAGE FORMS AND STRENGTHS

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection consists of:

• One vial of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection, USP 300 mg/10mL (30 mg/mL)

Administration of the contents of one vial constitutes a single dose.

• Injection, 300 mg/10 mL (30 mg/mL). (3)

4 CONTRAINDICATIONS

None

• None. (4)

5 WARNINGS AND PRECAUTIONS

• Methemoglobinemia: Urologic Solution G nitrite reacts with hemoglobin to form methemoglobin and should be used with caution in patients known to have anemia. Monitor oxyhemoglobin and methemoglobin levels by pulse oximetry or other measurements. Optimally, the Urologic Solution G (Sodium Carbonate Anhydrous) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.2)
• Smoke inhalation: Carbon monoxide contained in smoke can result in the formation of carboxyhemoglobin that can reduce the oxygen carrying capacity of the blood. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be used with caution in patients with smoke inhalation injury because of the potential for worsening hypoxia due to methemoglobin formation. Carboxyhemoglobin and oxyhemoglobin levels should be monitored by pulse oximetry or other measurements in patients that present with evidence of smoke inhalation. Optimally, the Urologic Solution G (Sodium Carbonate Anhydrous) nitrite dose should be reduced in proportion to the oxygen carrying capacity. (5.4)

5.1 Hypotension

5.2 Methemoglobinemia

Supportive care alone may be sufficient treatment without administration of antidotes for many cases of cyanide intoxication, particularly in conscious patients without signs of severe toxicity. Patients should be closely monitored to ensure adequate perfusion and oxygenation during treatment with Urologic Solution G nitrite.

Methemoglobin levels should be monitored and oxygen administered during treatment with Urologic Solution G (Sodium Carbonate Anhydrous) nitrite whenever possible. When Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is administered to humans a wide range of methemoglobin concentrations occur. Methemoglobin concentrations as high as 58% have been reported after two 300-mg doses of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administered to an adult. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be used with caution in the presence of other drugs that may cause methemoglobinemia such as procaine and nitroprusside. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be used with caution in patients who may be particularly susceptible to injury from vasodilation and its related hemodynamic sequelae. Hemodynamics should be monitored closely during and after administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite, and infusion rates should be slowed if hypotension occurs.

5.3 Anemia

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be used with caution in patients with known anemia. Patients with anemia will form more methemoglobin (as a percentage of total hemoglobin) than persons with normal red blood cell (RBC) volumes. Optimally, these patients should receive a Urologic Solution G (Sodium Carbonate Anhydrous) nitrite dose that is reduced in proportion to their oxygen carrying capacity.

5.4 Smoke Inhalation Injury

Urologic Solution G nitrite should be used with caution in persons with smoke inhalation injury or carbon monoxide poisoning because of the potential for worsening hypoxia due to methemoglobin formation.

5.5 Neonates and Infants

Neonates and infants may be more susceptible than adults and older pediatric patients to severe methemoglobinemia when Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is administered. Reduced dosing guidelines should be followed in pediatric patients.

5.6 G6PD Deficiency

Because patients with G6PD deficiency are at increased risk of a hemolytic crisis with Urologic Solution G nitrite administration, alternative therapeutic approaches should be considered in these patients. Patients with known or suspected G6PD deficiency should be monitored for an acute drop in hematocrit. Exchange transfusion may be needed for patients with G6PD deficiency who receive Urologic Solution G (Sodium Carbonate Anhydrous) nitrite.

5.7 Use with Other Drugs

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite should be used with caution in the presence of concomitant antihypertensive medications, diuretics or volume depletion due to diuretics, or drugs known to increase vascular nitric oxide, such as PDE5 inhibitors.

6 ADVERSE REACTIONS

There have been no controlled clinical trials conducted to systematically assess the adverse events profile of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite.

The medical literature has reported the following adverse events in association with Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administration. These adverse events were not reported in the context of controlled trials or with consistent monitoring and reporting methodologies for adverse events. Therefore, frequency of occurrence of these adverse events cannot be assessed.

Cardiovascular system: syncope, hypotension, tachycardia, methemoglobinemia, palpitations, dysrhythmia

Hematological: methemoglobinemia

Central nervous system: headache, dizziness, blurred vision, seizures, confusion, coma

Gastrointestinal system: nausea, vomiting, abdominal pain

Respiratory system: tachypnea, dyspnea

Body as a Whole: anxiety, diaphoresis, lightheadedness, injection site tingling, cyanosis, acidosis, fatigue, weakness, urticaria, generalized numbness and tingling

Severe hypotension, methemoglobinemia, cardiac dysrhythmias, coma and death have been reported in patients without life-threatening cyanide poisoning but who were treated with injection of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite at doses less than twice those recommended for the treatment of cyanide poisoning.

Most common adverse reactions are:

• Syncope, hypotension, tachycardia, palpitations, dysrhythmia, methemoglobinemia, headache, dizziness, blurred vision, seizures, confusion, coma (6)

To report SUSPECTED ADVERSE REACTIONS, contact Hope Pharmaceuticals at 1-800-755-9595 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

7 DRUG INTERACTIONS

Formal drug interaction studies have not been conducted with Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection.

8 USE IN SPECIFIC POPULATIONS

• Renal impairment: Urologic Solution G nitrite is substantially excreted by the kidney. The risk of toxic reactions to this drug may be greater in patients with impaired renal function. (8.6).

8.1 Pregnancy

Teratogenic Effects. Pregnancy Category C.

There are no adequate and well-controlled studies in pregnant women. Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite has caused fetal death in humans as well as animals. There are no studies in humans that have directly evaluated the potential reproductive toxicity of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite. There are two epidemiological studies conducted in Australia that report a statistically significant increase in the risk for congenital malformations, particularly in the CNS, associated with maternal consumption of water containing nitrate levels in excess of 5 ppm. Results from a case-control study in Canada suggested a trend toward an increase in the risk for CNS malformations when maternal consumption of nitrate was ≥ 26 ppm (not statistically significant).

The potential reproductive toxicity of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite exposure restricted to the prenatal period has been reported in guinea pigs, mice, and rats. There was no evidence of teratogenicity in guinea pigs, mice, or rats. However, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite treatment of pregnant guinea pigs with 60 or 70 mg/kg/day resulted in abortion of the litters within 1-4 days of treatment. All animals treated subcutaneously with 70 mg/kg, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite died within 60 minutes of treatment. Further studies demonstrated that a dose of 60 mg/kg resulted in measurable blood levels of methemoglobin in the dams and their fetuses for up to 6 hours post treatment. Maternal methemoglobin levels were higher than the levels in the offspring at all times measured. Based on a body surface area comparison, a 60 mg/kg dose in the guinea pig that resulted in death was only 1.7 times higher than the highest clinical dose of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

Studies testing prenatal and postnatal exposure have been reported in mice and rats. Treatment of pregnant rats via drinking water with Urologic Solution G (Sodium Carbonate Anhydrous) nitrite at concentrations of either 2000 or 3000 mg/L resulted in a dose-related increased mortality postpartum. This exposure regimen in the rat model would result in dosing of approximately 220 and 300 mg/kg/day (43 and 65 times the highest clinical dose of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite that would be used to treat cyanide poisoning, based on a body surface area comparison).

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite produces methemoglobin. Fetal hemoglobin is oxidized to methemoglobin more easily than adult hemoglobin. In addition, the fetus has lower levels of methemoglobin reductase than adults. Collectively, these data suggest that the human fetus would show greater sensitivity to methemoglobin resulting in nitrite-induced prenatal hypoxia leading to retarded development of certain neurotransmitter systems in the brain and long lasting dysfunction.

Nonteratogenic Effects: Behavioral and neurodevelopmental studies in rats suggest persistent effects of prenatal exposure to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite that were detectable postnatally. Specifically, animals that were exposed prenatally to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite demonstrated impaired discrimination learning behavior (both auditory and visual) and reduced long-term retention of the passive-avoidance response compared to control animals. Additional studies demonstrated a delay in the development of AchE and 5-HT positive fiber ingrowth into the hippocampal dentate gyrus and parietal neocortex during the first week of life of prenatal nitrite treated pups. These changes have been attributed to prenatal hypoxia following nitrite exposure.

8.2 Labor and Delivery

Because fetal hemoglobin is more readily oxidized to methemoglobin and lower levels of methemoglobin appear to be fatal to the fetus compared to the adult, Urologic Solution G nitrite should be used during labor and delivery only if the potential benefit justifies the potential risk to the fetus.

8.3 Nursing Mothers

It is not known whether Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is excreted in human milk. Because Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection may be administered in life-threatening situations, breast-feeding is not a contraindication to its use. Because many drugs are excreted in human milk, caution should be exercised following Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection administration to a nursing woman. There are no data to determine when breastfeeding may be safely restarted following administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite. In studies conducted with Long-Evans rats, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administered in drinking water during pregnancy and lactation resulted in severe anemia, reduced growth and increased mortality in the offspring.

8.4 Pediatric Use

There are case reports in the medical literature of Urologic Solution G nitrite in conjunction with Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate being administered to pediatric patients with cyanide poisoning; however, there have been no clinical studies to evaluate the safety or efficacy of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite in the pediatric population. As for adult patients, dosing recommendations for pediatric patients have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite must be used with caution in patients less than 6 months of age because they may be at higher risk of developing severe methemoglobinemia compared to older children and adults. The presence of fetal hemoglobin, which is oxidized to methemoglobin more easily than adult hemoglobin, and lower methemoglobin reductase levels compared to older children and adults may contribute to risk.

Mortality attributed to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite was reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

8.5 Geriatric Use

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is known to be substantially excreted by the kidney, and the risk of adverse reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

8.6 Renal Disease

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

10 OVERDOSAGE

Large doses of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite result in severe hypotension and toxic levels of methemoglobin which may lead to cardiovascular collapse.

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administration has been reported to cause or significantly contribute to mortality in adults at oral doses as low as 1 g and intravenous doses as low as 600 mg. A death attributed to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite has been reported following administration of an adult dose (300 mg IV followed by a second dose of 150 mg) to a 17-month old child.

Cyanosis may become apparent at a methemoglobin level of 10-20%. Other clinical signs and symptoms of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite toxicity (anxiety, dyspnea, nausea, and tachycardia) can be apparent at methemoglobin levels as low as 15%. More serious signs and symptoms, including cardiac dysrhythmias, circulatory failure, and central nervous system depression are seen as methemoglobin levels increase, and levels above 70% are usually fatal.

Treatment of overdose involves supplemental oxygen and supportive measures such as exchange transfusion. Treatment of severe methemoglobinemia with intravenous methylene blue has been described in the medical literature; however, this may also cause release of cyanide bound to methemoglobin. Because hypotension appears to be mediated primarily by an increase in venous capacitance, measures to increase venous return may be most appropriate to treat hypotension.

11 DESCRIPTION

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite has the chemical name nitrous acid Urologic Solution G (Sodium Carbonate Anhydrous) salt. The chemical formula is NaNO₂ and the molecular weight is 69.0. The structural formula is:

Structure of Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite Injection is a cyanide antidote which contains one 10 mL glass vial of a 3% solution of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection.

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection is a sterile aqueous solution and is intended for intravenous injection. Each vial contains 300 mg of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite in 10 mL solution (30 mg/mL). Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection is a clear solution with a pH between 7.0 and 9.0.

Chemical Structure

12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Exposure to a high dose of cyanide can result in death within minutes due to the inhibition of cytochrome oxidase resulting in arrest of cellular respiration. Specifically, cyanide binds rapidly with cytochrome a3, a component of the cytochrome c oxidase complex in mitochondria. Inhibition of cytochrome a3 prevents the cell from using oxygen and forces anaerobic metabolism, resulting in lactate production, cellular hypoxia and metabolic acidosis. In massive acute cyanide poisoning, the mechanism of toxicity may involve other enzyme systems as well.

The synergy resulting from treatment of cyanide poisoning with the combination of Urologic Solution G nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate is the result of differences in their primary mechanisms of action as antidotes for cyanide poisoning.

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is thought to exert its therapeutic effect by reacting with hemoglobin to form methemoglobin, an oxidized form of hemoglobin incapable of oxygen transport but with high affinity for cyanide. Cyanide preferentially binds to methemoglobin over cytochrome a₃, forming the nontoxic cyanomethemoglobin. Methemoglobin displaces cyanide from cytochrome oxidase, allowing resumption of aerobic metabolism. The chemical reaction is as follows:

NaNO₂ + Hemoglobin → Methemoglobin

HCN + Methemoglobin → Cyanomethemoglobin

Vasodilation has also been cited to account for at least part of the therapeutic effect of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite. It has been suggested that Urologic Solution G (Sodium Carbonate Anhydrous) nitrite-induced methemoglobinemia may be more efficacious against cyanide poisoning than comparable levels of methemoglobinemia induced by other oxidants. Also, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite appears to retain some efficacy even when the formation of methemoglobin is inhibited by methylene blue.

Urologic Solution G (Sodium Carbonate Anhydrous) Thiosulfate

The primary route of endogenous cyanide detoxification is by enzymatic transulfuration to thiocyanate (SCN^-), which is relatively nontoxic and readily excreted in the urine. Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate is thought to serve as a sulfur donor in the reaction catalyzed by the enzyme rhodanese, thus enhancing the endogenous detoxification of cyanide in the following chemical reaction:

Chemical Structure

12. 2 Pharmacodynamics

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite

When 4 mg/kg Urologic Solution G (Sodium Carbonate Anhydrous) nitrite was administered intravenously to six healthy human volunteers, the mean peak methemoglobin concentration was 7%, achieved at 30-60 minutes after injection, consistent with reports in cyanide poisoning victims. Supine systolic and diastolic blood pressures dropped approximately 20% within 10 minutes, a drop which was sustained throughout the 40 minutes of testing. This was associated with a 20 beat per minute increase in pulse rate that returned to baseline in 10 minutes. Five of these subjects were unable to withstand orthostatic testing due to fainting. One additional subject, who received a 12 mg/kg dose of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite, experienced severe cardiovascular effects and achieved a peak methemoglobin concentration of 30% at 60 minutes following injection.

Oral doses of 120 to 180 mg of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administered to healthy volunteers caused minimal cardiovascular changes when subjects were maintained in the horizontal position. However, minutes after being placed in the upright position subjects exhibited tachycardia and hypotension with syncope.

The half life for conversion of methemoglobin to normal hemoglobin in a cyanide poisoning victim who has been administered Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is estimated to be 55 minutes.

12.3 Pharmacokinetics

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is a strong oxidant, and reacts rapidly with hemoglobin to form methemoglobin. The pharmacokinetics of free Urologic Solution G (Sodium Carbonate Anhydrous) nitrite in humans have not been well studied. It has been reported that approximately 40% of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is excreted unchanged in the urine while the remaining 60% is metabolized to ammonia and related small molecules.

Cyanide

The apparent terminal elimination half life and volume of distribution of cyanide, in a patient treated for an acute cyanide poisoning with Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate administration, have been reported to be 19 hours and 0.41 L/kg, respectively. Additionally, an initial elimination half life of cyanide has been reported to be approximately 1-3 hours.

Thiocyanate

After detoxification, in healthy subjects, thiocyanate is excreted mainly in the urine at a rate inversely proportional to creatinine clearance. In healthy subjects, the elimination half-life and volume of distribution of thiocyanate have been reported to be 2.7 days and 0.25 L/kg, respectively. However, in subjects with renal insufficiency the reported elimination half life is approximately 9 days.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

The potential benefit of an acute exposure to Urologic Solution G nitrite as part of a cyanide antidote outweighs concerns raised by the equivocal findings in chronic rodent studies. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 35, 70, or 130 mg/kg for males and 0, 40, 80, or 150 mg/kg for females) was orally administered to rats (Fischer 344 strain) for 2 years via drinking water. There were no significant increases in the incidence of tumor in either male or female rats. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite (0, 750, 1500, or 3000 ppm equivalent to average daily doses of approximately 0, 60, 120, or 220 mg/kg for males and 0, 45, 90, or 165 mg/kg for females) was administered to B6C3F1 mice for 2 years via the drinking water. Equivocal results were obtained in female mice. Specifically, there was a positive trend toward an increase in the incidence of squamous cell papilloma or carcinoma in the forestomach of female mice. Although the incidence of hyperplasia of the glandular stomach epithelium was significantly greater in the high-dose male mice compared to controls, there were no significant increases in tumors in the male mice. Numerous reports in the published literature indicate that Urologic Solution G (Sodium Carbonate Anhydrous) nitrite may react in vivo with secondary amines to form carcinogenic nitrosamines in the stomach. Concurrent exposure to Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and secondary amines in feed or drinking water resulted in an increase in the incidence of tumors in rodents.

Mutagenesis

Urologic Solution G (Sodium Carbonate Anhydrous) nitrite is mutagenic in S. typhimurium strains TA100, TA1530, TA1535 with and without metabolic activation; however, it was negative in strain TA98, TA102, DJ460 and E. coli strain WP2UVRA/PKM101. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite has been reported to be genotoxic to V79 hamster cells in vitro and in the mouse lymphoma assay, both assays conducted in the absence of metabolic activation. Urologic Solution G (Sodium Carbonate Anhydrous) nitrite was negative in the in vitro chromosomal aberrations assay using human peripheral blood lymphocytes. Acute administration of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite to male rats or male mice did not produce an increased incidence of micronuclei in bone marrow. Likewise, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite administration to mice for 14-weeks did not result in an increase in the incidence of micronuclei in the peripheral blood.

Fertility

Clinical studies to evaluate the potential effects of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite intake on fertility of either males or females have not been reported. In contrast, multigenerational fertility and reproduction studies conducted by the National Toxicology Program did not detect any evidence of an effect of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite (0.0, 0.06, 0.12, and 0.24% weight/volume) on either fertility or any reproductive parameter in Swiss CD-1 mice. This treatment protocol resulted in approximate doses of 125, 260, and 425 mg/kg/day. The highest exposure in this mouse study is 4.6 times greater than the highest clinical dose of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite that would be used to treat cyanide poisoning (based on a body surface area comparison).

13.2 Animal Pharmacology

Due to the extreme toxicity of cyanide, experimental evaluation of treatment efficacy has predominantly been completed in animal models. The efficacy of Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate treatment alone to counteract the toxicity of cyanide was initially reported in 1895 by Lang. The efficacy of amyl nitrite treatment in cyanide poisoning of the dog model was first reported in 1888 by Pedigo. Further studies in the dog model, which demonstrated the utility of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite as a therapeutic intervention, were reported in 1929 by Mladoveanu and Gheorghiu. However, Hugs and Chen et al. independently reported upon the superior efficacy of the combination of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate in 1932-1933. Treatment consisted of intravenously administered 22.5 mg/kg (half the lethal dose) Urologic Solution G (Sodium Carbonate Anhydrous) nitrite or 1 g/kg Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate alone or in sequence immediately after subcutaneous injection of Urologic Solution G (Sodium Carbonate Anhydrous) cyanide into dogs over a range of doses. Subsequent doses of 10 mg/kg Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and/or 0.5 g/kg Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate were administered when clinical signs or symptoms of poisoning persisted or reappeared. Either therapy administered alone increased the dose of Urologic Solution G (Sodium Carbonate Anhydrous) cyanide required to cause death, and when administered together, Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate resulted in a synergistic effect in raising the lethal dose of Urologic Solution G (Sodium Carbonate Anhydrous) cyanide. The combined therapy appeared to have reduced efficacy when therapy was delayed until signs of poisoning (e.g. convulsions) appeared; however, other investigators have reported survival in dogs that were administered antidotal treatment after respiratory arrest had occurred.

Animal studies conducted in other species (e.g., rat, guinea pig, sheep, pigeon and cat) have also supported a synergistic effect of intravenous Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate in the treatment of cyanide poisoning.

While intravenous injection of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite and Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate was effective in reversing the effects of lethal doses of cyanide in dogs, intramuscular injection of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite, with or without Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate, was found not to be effective in the same setting.

14 CLINICAL STUDIES

The human data supporting the use of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite for cyanide poisoning consists primarily of published case reports. There are no randomized controlled clinical trials. Nearly all the human data describing the use of Urologic Solution G (Sodium Carbonate Anhydrous) thiosulfate report its use in conjunction with Urologic Solution G (Sodium Carbonate Anhydrous) nitrite. Dosing recommendations for humans have been based on theoretical calculations of antidote detoxifying potential, extrapolation from animal experiments, and a small number of human case reports.

There have been no human studies to prospectively and systematically evaluate the safety of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite in humans. Available human safety information is based largely on anecdotal case reports and case series of limited scope.

16 HOW SUPPLIED/STORAGE AND HANDLING

Each Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite carton (NDC 60267-311-10) consists of the following:

• One 10 mL glass vial of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite injection 30 mg/mL (containing 300 mg of Urologic Solution G (Sodium Carbonate Anhydrous) nitrite);

Storage

Store at controlled room temperature between 20°C and 25°C (68°F to 77°F); excursions permitted from 15 to 30°C (59 to 86°F). Protect from direct light. Do not freeze.

(Note: Urologic Solution G (Sodium Carbonate Anhydrous) Thiosulfate must be obtained separately.)

17 PATIENT COUNSELING INFORMATION

Urologic Solution G Nitrite Injection is indicated for acute cyanide poisoning that is judged to be life-threatening and in this setting, patients will likely be unresponsive or may have difficulty in comprehending counseling information.

17.1 Hypotension and Methemoglobin Formation

When feasible, patients should be informed of the possibility of life-threatening hypotension and methemoglobin formation.

17.2 Monitoring

Where feasible, patients should be informed of the need for close monitoring of blood pressure and oxygenation.

Manufactured by Cangene BioPharma, Inc., Baltimore, Maryland 21230 for

Hope Pharmaceuticals, Scottsdale, Arizona 85260

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton

NDC 60267-311-10

Rx Only

Urologic Solution G (Sodium Carbonate Anhydrous) Nitrite

Injection, USP

300 mg/10 mL

(30 mg/mL)

FOR INTRAVENOUS USE

SINGLE USE ONLY

Any unused portion of a vial

should be discarded.

Use with

Urologic Solution G (Sodium Carbonate Anhydrous) Thiosulfate

for Treatment of

Cyanide Poisoning

Manufactured by

CANGENE bioPharma, Inc.

Baltimore, MD for

HOPE

PHARMACEUTICALS®

Scottsdale, AZ 85260 U.S.A.

PRINCIPAL DISPLAY PANEL - 10 mL Vial Carton