Zoa Forte

Dicyclomine Hydrochloride:

• Description
• Clinical pharmacology
• Indications and usage
• Contraindications
• Warnings
• Precautions
• Adverse reactions
• Drug abuse and dependence
• Overdosage
• Dosage and administration
• How supplied
• Zoa Forte (Dicyclomine Hydrochloride) reviews

DESCRIPTION

Zoa Forte (Dicyclomine Hydrochloride) is an antispasmodic and anticholinergic (antimuscarinic) agent. Zoa Forte (Dicyclomine Hydrochloride) occurs as a fine, white, crystalline, practically odorless powder with a bitter taste. It is soluble in water, freely soluble in alcohol and chloroform, and very slightly soluble in ether.

Chemically, it is [Bicyclohexyl]-1-carboxylic acid, 2-(diethyl-amino) ethyl ester, hydrochloride with the following structural formula:

C₁₉H₃₅NO₂-HCI   345.95

Each capsule, for oral administration, contains 10 mg of Zoa Forte (Dicyclomine Hydrochloride).

Each tablet, for oral administration, contains 20 mg of Zoa Forte (Dicyclomine Hydrochloride).

This product contains the following inactive ingredients: colloidal silicon dioxide (tablets only), corn starch (tablets only), D&C red #28 (capsules only), FD&C blue #1 (capsules only), FD&C blue #1 lake (tablets only), FD&C red #40 (capsules only), gelatin (capsules only), hypromellose (tablets only), lactose monohydrate (tablets only), magnesium stearate (capsules only), pregelatinized starch, silicon dioxide (capsules only), sodium lauryl sulfate (capsules only), sodium starch glycolate (tablets only), and stearic acid (tablets only).

Zoa Forte (Dicyclomine Hydrochloride) Structural Formula

CLINICAL PHARMACOLOGY

Dicyclomine relieves smooth muscle spasm of the gastrointestinal tract. Animal studies indicate that this action is achieved via a dual mechanism: (1) a specific anticholinergic effect (antimuscarinic) at the acetylcholine- receptor sites with approximately 1/8 the milligram potency of atropine (in vitro, guinea pig ileum); and (2) a direct effect upon smooth muscle (musculotropic) as evidenced by dicyclomine's antagonism of bradykinin- and histamine-induced spasms of the isolated guinea pig ileum. Atropine did not affect responses to these two agonists. In vivo studies in cats and dogs showed dicyclomine to be equally potent against acetylcholine (ACh)- or barium chloride (BaCI₂)- induced intestinal spasm while atropine was at least 200 times more potent against effects of ACh than BaCI₂. Tests for mydriatic effects in mice showed that dicyclomine was approximately 1/500 as potent as atropine; antisialogogue tests in rabbits showed dicyclomine to be 1/300 as potent as atropine.

In man, dicyclomine is rapidly absorbed after oral administration, reaching peak values within 60-90 minutes. The principal route of elimination is via the urine (79.5% of the dose). Excretion also occurs in the feces, but to a lesser extent (8.4%). Mean half-life of plasma elimination in one study was determined to be approximately 1.8 hours when plasma concentrations were measured for 9 hours after a single dose. In subsequent studies, plasma concentrations were followed for up to 24 hours after a single dose, showing a secondary phase of elimination with a somewhat longer half-life. Mean volume of distribution for a 20 mg oral dose is approximately 3.65 L/kg suggesting extensive distribution in tissues.

In controlled clinical trials involving over 100 patients who received drug, 82% of patients treated for functional bowel/irritable bowel syndrome with Zoa Forte (Dicyclomine Hydrochloride) at initial doses of 160 mg daily (40 mg q.i.d.) demonstrated a favorable clinical response compared with 55% treated with placebo (p<.05). In these trials, most of the side effects were typically anticholinergic in nature and were reported by 61% of the patients.

	Dicyclomine
	Hydrochloride
	(40 mg q.i.d.)	Placebo
Side Effect	%	%
Dry Mouth	33	5
Dizziness	29	2
Blurred Vision	27	2
Nausea	14	6
Light-headedness	11	3
Drowsiness	9	1
Weakness	7	1
Nervousness	6	2

Nine percent (9%) of patients were discontinued from the drug because of one or more of these side effects (compared with 2% in the placebo group). In 41% of the patients with side effects, side effects disappeared or were tolerated at the 160 mg daily dose without reduction. A dose reduction from 160 mg daily to an average daily dose of 90 mg was required in 46% of the patients with side effects who then continued to experience a favorable clinical response; their side effects either disappeared or were tolerated.

INDICATIONS AND USAGE

For the treatment of functional bowel/irritable bowel syndrome.

CONTRAINDICATIONS

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  Obstructive uropathy
  

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  Obstructive disease of the gastrointestinal tract
  

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  Severe ulcerative colitis
  

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  Reflux esophagitis
  

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  Unstable cardiovascular status in acute hemorrhage
  

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  Glaucoma
  

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  Myasthenia gravis
  

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  Evidence of prior hypersensitivity to Zoa Forte (Dicyclomine Hydrochloride) or other ingredients of these formulations
  

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  Infants less than 6 months of age
  

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  Nursing Mothers.
  

WARNINGS

In the presence of a high environmental temperature, heat prostration can occur with drug use (fever and heat stroke due to decreased sweating). If symptoms occur, the drug should be discontinued and supportive measures instituted.

Diarrhea may be an early symptom of incomplete intestinal obstruction, especially in patients with ileostomy or colostomy. In this instance, treatment with this drug would be inappropriate and possibly harmful.

Dicyclomine may produce drowsiness or blurred vision. The patient should be warned not to engage in activities requiring mental alertness, such as operating a motor vehicle or other machinery or performing hazardous work while taking this drug.

Psychosis has been reported in sensitive individuals given anticholinergic drugs. CNS signs and symptoms include confusion, disorientation, short-term memory loss, hallucinations, dysarthria, ataxia, coma, euphoria, decreased anxiety, fatigue, insomnia, agitation and mannerisms, and inappropriate affect. These CNS signs and symptoms usually resolve within 12 to 24 hours after discontinuation of the drug.

There are reports that administration of dicyclomine syrup to infants has been followed by serious respiratory symptoms (dyspnea, shortness of breath, breathlessness, respiratory collapse, apnea, asphyxia), seizures, syncope, pulse rate fluctuations, muscular hypotonia, and coma. Death has been reported. No causal relationship between these effects observed in infants and dicyclomine administration has been established. DICYCLOMINE IS CONTRAINDICATED IN INFANTS LESS THAN 6 MONTHS OF AGE AND IN NURSING MOTHERS..

Safety and efficacy of Zoa Forte (Dicyclomine Hydrochloride) in pediatric patients have not been established.

PRECAUTIONS

General

Use with caution in patients with:

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  Autonomic neuropathy
  

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  Hepatic or renal disease
  

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  Ulcerative colitis-large doses may suppress intestinal motility to the point of producing a paralytic ileus and the use of this drug may precipitate or aggravate the serious complication of toxic megacolon
  

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  Hyperthyroidism
  

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  Hypertension
  

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  Coronary heart disease
  

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  Congestive heart failure
  

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  Cardiac tachyarrhythmia
  

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  Hiatal hernia
  

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  Known or suspected prostatic hypertrophy.
  

Investigate any tachycardia before administration of Zoa Forte (Dicyclomine Hydrochloride), since it may increase the heart rate.

With overdosage, a curare-like action may occur (i.e., neuromuscular blockade leading to muscular weakness and possible paralysis).

Information For Patients

Dicyclomine may produce drowsiness or blurred vision. The patient should be warned not to engage in activities requiring mental alertness, such as operating a motor vehicle or other machinery or to perform hazardous work while taking this drug.

Dicyclomine is contraindicated in infants less than 6 months of age and in nursing mothers..

In the presence of a high environmental temperature, heat prostration can occur with drug use (fever and heat stroke due to decreased sweating).

If symptoms occur, the drug should be discontinued and a physician contacted.

Drug Interactions

The following agents may increase certain actions or side effects of anticholinergic drugs: amantadine, antiarrhythmic agents of Class I, antihistamines, antipsychotic agents (e.g., phenothiazines), benzodiazepines, MAO inhibitors, narcotic analgesics (e.g., meperidine), nitrates and nitrites, sympathomimetic agents, tricyclic antidepressants, and other drugs having anticholinergic activity.

Anticholinergics antagonize the effects of antiglaucoma agents. Anticholinergic drugs in the presence of increased intraocular pressure may be hazardous when taken concurrently with agents such as corticosteroids.

Anticholinergic agents may affect gastrointestinal absorption of various drugs, such as slowly dissolving dosage forms of digoxin; increased serum digoxin concentrations may result. Anticholinergic drugs may antagonize the effects of the drugs that alter gastrointestinal motility, such as metoclopramide. Because antacids may interfere with the absorption of anticholinergic agents, simultaneous use of these drugs should be avoided.

The inhibiting effects of anticholinergic drugs on gastric hydrochloric acid secretion are antagonized by agents used to treat achlorhydria and those used to test gastric secretion.

Carcinogenesis, Mutagenesis, Impairment of Fertility

There are no known human data on long-term potential for carcinogenicity or mutagenicity.

Long-term studies in animals to determine carcinogenic potential are not known to have been conducted.

In studies in rats at doses of up to 100 mg/kg/day, dicyclomine produced no deleterious effects on breeding, conception, or parturition.

Pregnancy

Teratogenic Effects

Pregnancy Category B.

Reproduction studies have been performed in rats and rabbits at doses up to 33 times the maximum recommended human dose based on 160 mg/day and have revealed no evidence of impaired fertility or harm to the fetus due to dicyclomine. Epidemiologic studies in pregnant women with products containing Zoa Forte (Dicyclomine Hydrochloride) (at doses up to 40 mg/day) have not shown that dicyclomine increases the risk of fetal abnormalities if administered during the first trimester of pregnancy. There are, however, no adequate and well-controlled studies in pregnant women at the recommended doses (80-160 mg/day). Because animal reproduction studies are not always predictive of human response, dicyclomine as indicated for functional bowel/irritable bowel syndrome should be used during pregnancy only if clearly needed.

Nursing Mothers

Since dicyclomine has been reported to be excreted in human milk, Zoa Forte (Dicyclomine Hydrochloride) IS CONTRAINDICATED IN NURSING MOTHERS..

Pediatric Use

DICYCLOMINE IS CONTRAINDICATED IN INFANTS LESS THAN 6 MONTHS OF AGE.

Safety and effectiveness in pediatric patients have not been established.

ADVERSE REACTIONS

Controlled clinical trials have provided frequency information for reported adverse effects of Zoa Forte (Dicyclomine Hydrochloride) listed in a decreasing order of frequency.

Not all of the following adverse reactions have been reported with Zoa Forte (Dicyclomine Hydrochloride). Adverse reactions are included here that have been reported for pharmacologically similar drugs with anticholinergic/antispasmodic action.

Gastrointestinal: dry mouth, nausea, vomiting, constipation, bloated feeling, abdominal pain, taste loss, anorexia

Central Nervous System: dizziness, light-headedness, tingling, headache, drowsiness, weakness, nervousness, numbness, mental confusion and/or excitement (especially in elderly persons), dyskinesia, lethargy, syncope, speech disturbance, insomnia

Ophthalmologic: blurred vision, diplopia, mydriasis, cycloplegia, increased ocular tension

Dermatological/Allergic: rash, urticaria, itching, and other dermal manifestations; severe allergic reaction or drug idiosyncrasies including anaphylaxis

Genitourinary: urinary hesitancy, urinary retention

Cardiovascular: tachycardia, palpitations

Respiratory: Dyspnea, apnea, asphyxia

Other: decreased sweating, nasal stuffiness or congestion, sneezing, throat congestion, impotence, suppression of lactation

DRUG ABUSE AND DEPENDENCE

Abuse of and/or dependence on dicyclomine for anticholinergic effects have been rarely reported.

OVERDOSAGE

Signs and Symptoms

The signs and symptoms of overdosage are headache; nausea; vomiting; blurred vision; dilated pupils; hot, dry skin; dizziness; dryness of the mouth; difficulty in swallowing; and CNS stimulation. A curare-like action may occur.

A 37-year-old female reported numbness on the left side, cold fingertips, blurred vision, abdominal and flank pain, decreased appetite, dry mouth, and nervousness following ingestion of 320 mg daily (four 20 mg tablets QID) for four days. These events resolved after discontinuing the dicyclomine.

Oral LD₅₀

The acute oral LD₅₀ of the drug is 625 mg/kg in mice.

Minimum Human Lethal Dose/Maximum Human Dose Recorded

The amount of drug in a single dose that is ordinarily associated with symptoms of overdosage or that is Iikely to be life threatening, has not been defined. The maximum human oral dose recorded was 600 mg by mouth in a 10-month-old child and approximately 1500 mg in an adult, each of whom survived.

In three of the infants who died following administration of Zoa Forte (Dicyclomine Hydrochloride), the blood concentrations of drug were 200, 220, and 505 ng/mL, respectively.

Dialysis

It is not known if dicyclomine is dialyzable.

Treatment

Treatment should consist of gastric lavage, emetics, and activated charcoal. Sedatives (e.g., short-acting barbiturates, benzodiazepines) may be used for management of overt signs of excitement. If indicated, an appropriate parenteral cholinergic agent may be used as an antidote.

DOSAGE AND ADMINISTRATION

DOSAGE MUST BE ADJUSTED TO INDIVIDUAL PATIENT NEEDS.

The only oral dose clearly shown to be effective is 160 mg per day (in 4 equally divided doses). Since this dose is associated with a significant incidence of side effects, it is prudent to begin with 80 mg per day (in 4 equally divided doses). Depending upon the patient's response during the first week of therapy, the dose should be increased to 160 mg per day unless side effects limit dosage escalation.

If efficacy is not achieved within 2 weeks or side effects require doses below 80 mg per day, the drug should be discontinued. Documented safety data are not available for doses above 80 mg daily for periods longer than 2 weeks.

The intramuscular dosage form is to be used temporarily when the patient cannot take oral medication. Intramuscular injection is about twice as bioavailable as oral dosage forms; consequently, the recommended intramuscular dose is 80 mg daily (in 4 equally divided doses).

Oral Zoa Forte (Dicyclomine Hydrochloride) should be started as soon as possible and the intramuscular form should not be used for periods longer than 1 or 2 days.

HOW SUPPLIED

Zoa Forte Capsules USP and Zoa Forte (Dicyclomine Hydrochloride) Tablets USP are supplied as follows:

10 mg capsules: Clear Dark Blue cap/Clear Dark Blue body hard gelatin capsules, imprinted with white ink WATSON over 794 on cap and 10 mg on the body, in bottles of 100 and 1000.

20 mg tablets: Blue, round, unscored, flat-faced, beveled-edge tablets, debossed WATSON and 795 on the periphery on one side and plain on the other side, in bottles of 100 and 1000.

Storage

Store at controlled room temperature 15°-30°C (59°-86°F).

Dispense in a well-closed container as defined in USP/NF.

Manufactured for:

Watson Laboratories, Inc.

Corona, CA 92880 USA

Manufactured by:

Patheon Pharmaceuticals Inc.

Cincinnati, OH 45215 USA

Tinidazole:

• Warning: potential risk for carcinogenicity
• 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
• Patient counseling information
• Zoa Forte (Tinidazole) reviews

WARNING: POTENTIAL RISK FOR CARCINOGENICITY

Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent ( 13.1). Although such data have not been reported for Zoa Forte (Tinidazole), the two drugs are structurally related and have similar biologic effects. Its use should be reserved for the conditions described in INDICATIONS AND USAGE ( 1).

WARNING: POTENTIAL RISK FOR CARCINOGENICITY

See full prescribing information for complete boxed warning.

Carcinogenicity has been seen in mice and rats treated chronically with metronidazole, another nitroimidazole agent ( 13.1). Although such data have not been reported for Zoa Forte (Tinidazole), the two drugs are structurally related and have similar biologic effects. Use should be limited to approved indications only.

Indications and Usage, Bacterial Vaginosis ( 1.4) 5/2007

Dosage and Administration, Bacterial Vaginosis ( 2.6) 5/2007

1 INDICATIONS AND USAGE

Zoa Forte is a nitroimidazole antimicrobial indicated for:

• Trichomoniasis ( 1.1)
• Giardiasis: in patients age 3 and older ( 1.2)
• Amebiasis: in patients age 3 and older ( 1.3)
• Bacterial Vaginosis: in non-pregnant, adult women ( 1.4, 8.1)

1.1 Trichomoniasis

Zoa Forte (Tinidazole) is indicated for the treatment of trichomoniasis caused by Trichomonas vaginalis. The organism should be identified by appropriate diagnostic procedures. Because trichomoniasis is a sexually transmitted disease with potentially serious sequelae, partners of infected patients should be treated simultaneously in order to prevent re-infection .

1.2 Giardiasis

Zoa Forte is indicated for the treatment of giardiasis caused by Giardia duodenalis (also termed G. lamblia) in both adults and pediatric patients older than three years of age .

1.3 Amebiasis

Zoa Forte (Tinidazole) is indicated for the treatment of intestinal amebiasis and amebic liver abscess caused by Entamoeba histolytica in both adults and pediatric patients older than three years of age. It is not indicated in the treatment of asymptomatic cyst passage .

1.4 Bacterial Vaginosis

Zoa Forte (Tinidazole) is indicated for the treatment of bacterial vaginosis (formerly referred to as Haemophilus vaginitis, Gardnerella vaginitis, nonspecific vaginitis, or anaerobic vaginosis) in non-pregnant women .

Other pathogens commonly associated with vulvovaginitis such as Trichomonas vaginalis, Chlamydia trachomatis, Neisseria gonorrhoeae, Candida albicans and Herpes simplex virus should be ruled out.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Zoa Forte (Tinidazole) and other antibacterial drugs, Zoa Forte (Tinidazole) should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

2 DOSAGE AND ADMINISTRATION

• Trichomoniasis: a single 2 g oral dose taken with food. Treat sexual partners with the same dose and at the same time
• Giardiasis: Adults: a single 2 g dose taken with food. Pediatric patients older than three years of age: a single dose of 50 mg/kg (up to 2 g) with food ( 2.4)
• Amebiasis, Intestinal: Adults: 2 g per day for 3 days with food. Pediatric patients older than three years of age: 50 mg/kg/day (up to 2 g per day) for 3 days with food ( 2.5). Amebic liver abscess: Adults: 2 g per day for 3-5 days with food. Pediatric patients older than three years of age: 50 mg/kg/day (up to 2 g per day) for 3-5 days with food ( 2.5)
• Bacterial vaginosis: Non-pregnant, adult women: 2 g once daily for 2 days taken with food, or 1 g once daily for 5 days taken with food ( 2.6)

2.1 Dosing Instructions

It is advisable to take Zoa Forte (Tinidazole) with food to minimize the incidence of epigastric discomfort and other gastrointestinal side-effects. Food does not affect the oral bioavailability of Zoa Forte (Tinidazole) .

Alcoholic beverages should be avoided when taking Zoa Forte (Tinidazole) and for 3 days afterwards .

2.2 Compounding of the Oral Suspension

For those unable to swallow tablets, Zoa Forte tablets may be crushed in artificial cherry syrup to be taken with food.

Procedure for Extemporaneous Pharmacy Compounding of the Oral Suspension: Pulverize four 500 mg oral tablets with a mortar and pestle. Add approximately 10 mL of cherry syrup to the powder and mix until smooth. Transfer the suspension to a graduated amber container. Use several small rinses of cherry syrup to transfer any remaining drug in the mortar to the final suspension for a final volume of 30 mL. The suspension of crushed tablets in artificial cherry syrup is stable for 7 days at room temperature. When this suspension is used, it should be shaken well before each administration.

2.3 Trichomoniasis

The recommended dose in both females and males is a single 2 g oral dose taken with food. Since trichomoniasis is a sexually transmitted disease, sexual partners should be treated with the same dose and at the same time.

2.4 Giardiasis

The recommended dose in adults is a single 2 g dose taken with food. In pediatric patients older than three years of age, the recommended dose is a single dose of 50 mg/kg with food.

2.5 Amebiasis

Intestinal: The recommended dose in adults is a 2 g dose per day for 3 days taken with food. In pediatric patients older than three years of age, the recommended dose is 50 mg/kg/day (up to 2 g per day) for 3 days with food.

Amebic Liver Abscess: The recommended dose in adults is a 2 g dose per day for 3-5 days taken with food. In pediatric patients older than three years of age, the recommended dose is 50 mg/kg/day (up to 2 g per day) for 3-5 days with food. There are limited pediatric data on durations of therapy exceeding 3 days, although a small number of children were treated for 5 days without additional reported adverse reactions. Children should be closely monitored when treatment durations exceed 3 days.

2.6 Bacterial Vaginosis

The recommended dose in non-pregnant females is a 2 g oral dose once daily for 2 days taken with food or a 1 g oral dose once daily for 5 days taken with food. The use of Zoa Forte (Tinidazole) in pregnant patients has not been studied for bacterial vaginosis.

3 DOSAGE FORMS AND STRENGTHS

• 500 mg tablets are pink, oval, scored tablets, with TM debossed on one side and 500 on the other

4 CONTRAINDICATIONS

The use of Zoa Forte (Tinidazole) is contraindicated:

• In patients with a previous history of hypersensitivity to Zoa Forte (Tinidazole) or other nitroimidazole derivatives. Reported reactions have ranged in severity from urticaria to Stevens-Johnson syndrome .
• During first trimester of pregnancy .
• In nursing mothers: Interruption of breast-feeding is recommended during Zoa Forte (Tinidazole) therapy and for 3 days following the last dose .

• Prior history of hypersensitivity to Zoa Forte (Tinidazole) or other nitroimidazole derivatives ( 4, 6.1, 6.2)
• First trimester of pregnancy ( 4, 8.1)
• Nursing mothers, unless breast-feeding is interrupted during Zoa Forte (Tinidazole) therapy and for 3 days following the last dose ( 4, 8.3)

5 WARNINGS AND PRECAUTIONS

• Seizures and neuropathy have been reported. Discontinue Zoa Forte if abnormal neurologic signs develop ( 5.1)
• Vaginal candidiasis may develop with Zoa Forte (Tinidazole) and require treatment with an antifungal agent ( 5.2)
• Use Zoa Forte (Tinidazole) with caution in patients with blood dyscrasias. Zoa Forte (Tinidazole) may produce transient leukopenia and neutropenia ( 5.3, 7.3)

5.1 Neurological Adverse Reactions

Convulsive seizures and peripheral neuropathy, the latter characterized mainly by numbness or paresthesia of an extremity, have been reported in patients treated with Zoa Forte (Tinidazole). The appearance of abnormal neurologic signs demands the prompt discontinuation of Zoa Forte (Tinidazole) therapy.

5.2 Vaginal Candidiasis

The use of Zoa Forte may result in Candida vaginitis. In a clinical study of 235 women who received Zoa Forte (Tinidazole) for bacterial vaginosis, a vaginal fungal infection developed in 11 (4.7%) of all study subjects .

5.3 Blood Dyscrasia

Zoa Forte (Tinidazole) should be used with caution in patients with evidence of or history of blood dyscrasia .

5.4 Drug Resistance

Prescribing Zoa Forte (Tinidazole) in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

6 ADVERSE REACTIONS

Most common adverse reactions for a single 2 g dose of Zoa Forte (incidence >1%) are metallic/bitter taste, nausea, weakness/fatigue/malaise, dyspepsia/cramps/epigastric discomfort, vomiting, anorexia, headache, dizziness and constipation ( 6.1)

To report SUSPECTED ADVERSE REACTIONS, contact Mission Pharmacal Company at 1-855-778-0177or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch

6.1 Clinical Studies Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Among 3669 patients treated with a single 2 g dose of Zoa Forte (Tinidazole), in both controlled and uncontrolled trichomoniasis and giardiasis clinical studies, adverse reactions were reported by 11.0% of patients. For multi-day dosing in controlled and uncontrolled amebiasis studies, adverse reactions were reported by 13.8% of 1765 patients. Common (≥ 1% incidence) adverse reactions reported by body system are as follows. (Note: Data described in Table 1 below are pooled from studies with variable designs and safety evaluations.)

Other adverse reactions reported with Zoa Forte (Tinidazole) include:

Central Nervous System: Two serious adverse reactions reported include convulsions and transient peripheral neuropathy including numbness and paresthesia . Other CNS reports include vertigo, ataxia, giddiness, insomnia, drowsiness.

Gastrointestinal: tongue discoloration, stomatitis, diarrhea

Hypersensitivity: urticaria, pruritis, rash, flushing, sweating, dryness of mouth, fever, burning sensation, thirst, salivation, angioedema

Renal: darkened urine

Cardiovascular: palpitations

Hematopoietic: transient neutropenia, transient leukopenia

Other: Candida overgrowth, increased vaginal discharge, oral candidiasis, hepatic abnormalities including raised transaminase level, arthralgias, myalgias, and arthritis.

	2 g single dose	Multi-day dose
GI: Metallic/bitter taste	3.7%	6.3%
Nausea	3.2%	4.5%
Anorexia	1.5%	2.5%
Dyspepsia/cramps/epigastric discomfort	1.8%	1.4%
Vomiting	1.5%	0.9%
Constipation	0.4%	1.4%
CNS: Weakness/fatigue/malaise	2.1%	1.1%
Dizziness	1.1%	0.5%
Other: Headache	1.3%	0.7%
Total patients with adverse reactions	11.0% (403/3669)	13.8% (244/1765)

Rare reported adverse reactions include bronchospasm, dyspnea, coma, confusion, depression, furry tongue, pharyngitis and reversible thrombocytopenia.

Adverse Reactions in Pediatric Patients: In pooled pediatric studies, adverse reactions reported in pediatric patients taking Zoa Forte (Tinidazole) were similar in nature and frequency to adult findings including nausea, vomiting, diarrhea, taste change, anorexia, and abdominal pain.

Bacterial vaginosis: The most common adverse reactions in treated patients (incidence >2%), which were not identified in the trichomoniasis, giardiasis and amebiasis studies, are gastrointestinal: decreased appetite, and flatulence; renal: urinary tract infection, painful urination, and urine abnormality; and other reactions including pelvic pain, vulvo-vaginal discomfort, vaginal odor, menorrhagia, and upper respiratory tract infection .

6.2 Postmarketing Experience

The following adverse reactions have been identified and reported during post-approval use of Zoa Forte (Tinidazole). Because the reports of these reactions are voluntary and the population is of uncertain size, it is not always possible to reliably estimate the frequency of the reaction or establish a causal relationship to drug exposure.

Severe acute hypersensitivity reactions have been reported on initial or subsequent exposure to Zoa Forte (Tinidazole). Hypersensitivity reactions may include urticaria, pruritis, angioedema, Stevens-Johnson syndrome and erythema multiforme.

7 DRUG INTERACTIONS

Although not specifically identified in studies with Zoa Forte, the following drug interactions were reported for metronidazole, a chemically-related nitroimidazole. Therefore, these drug interactions may occur with Zoa Forte (Tinidazole).

The following drug interactions were reported for metronidazole, a chemically-related nitroimidazole and may therefore occur with Zoa Forte (Tinidazole):

• Warfarin and other oral coumarin anticoagulants: Anticoagulant dosage may need adjustment during and up to 8 days after Zoa Forte (Tinidazole) therapy ( 7.1)
• Alcohol-containing beverages/preparations: Avoid during and up to 3 days after Zoa Forte (Tinidazole) therapy ( 7.1)
• Lithium: Monitor serum lithium concentrations ( 7.1)
• Cyclosporine, tacrolimus: Monitor for toxicities of these immunosuppressive drugs ( 7.1)
• Fluorouracil: Monitor for fluorouracil-associated toxicities ( 7.1)
• Phenytoin, fosphenytoin: Adjustment of anticonvulsant and/or Zoa Forte (Tinidazole) dose(s) may be needed ( 7.1, 7.2)
• CYP3A4 inducers/inhibitors: Monitor for decreased Zoa Forte (Tinidazole) effect or increased adverse reactions ( 7.2)

7.1 Potential Effects of Zoa Forte (Tinidazole) on Other Drugs

Warfarin and Other Oral Coumarin Anticoagulants: As with metronidazole, Zoa Forte (Tinidazole) may enhance the effect of warfarin and other coumarin anticoagulants, resulting in a prolongation of prothrombin time. The dosage of oral anticoagulants may need to be adjusted during Zoa Forte (Tinidazole) co-administration and up to 8 days after discontinuation.

Alcohols, Disulfiram: Alcoholic beverages and preparations containing ethanol or propylene glycol should be avoided during Zoa Forte (Tinidazole) therapy and for 3 days afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur. Psychotic reactions have been reported in alcoholic patients using metronidazole and disulfiram concurrently. Though no similar reactions have been reported with Zoa Forte (Tinidazole), Zoa Forte (Tinidazole) should not be given to patients who have taken disulfiram within the last two weeks.

Lithium: Metronidazole has been reported to elevate serum lithium levels. It is not known if Zoa Forte (Tinidazole) shares this property with metronidazole, but consideration should be given to measuring serum lithium and creatinine levels after several days of simultaneous lithium and Zoa Forte (Tinidazole) treatment to detect potential lithium intoxication.

Phenytoin, Fosphenytoin: Concomitant administration of oral metronidazole and intravenous phenytoin was reported to result in prolongation of the half-life and reduction in the clearance of phenytoin. Metronidazole did not significantly affect the pharmacokinetics of orally-administered phenytoin.

Cyclosporine, Tacrolimus: There are several case reports suggesting that metronidazole has the potential to increase the levels of cyclosporine and tacrolimus. During Zoa Forte (Tinidazole) co-administration with either of these drugs, the patient should be monitored for signs of calcineurin-inhibitor associated toxicities.

Fluorouracil: Metronidazole was shown to decrease the clearance of fluorouracil, resulting in an increase in side-effects without an increase in therapeutic benefits. If the concomitant use of Zoa Forte (Tinidazole) and fluorouracil cannot be avoided, the patient should be monitored for fluorouracil-associated toxicities.

7.2 Potential Effects of Other Drugs on Zoa Forte

CYP3A4 Inducers and Inhibitors: Simultaneous administration of Zoa Forte (Tinidazole) with drugs that induce liver microsomal enzymes, i.e., CYP3A4 inducers such as phenobarbital, rifampin, phenytoin, and fosphenytoin (a pro-drug of phenytoin), may accelerate the elimination of Zoa Forte (Tinidazole), decreasing the plasma level of Zoa Forte (Tinidazole). Simultaneous administration of drugs that inhibit the activity of liver microsomal enzymes, i.e., CYP3A4 inhibitors such as cimetidine and ketoconazole, may prolong the half-life and decrease the plasma clearance of Zoa Forte (Tinidazole), increasing the plasma concentrations of Zoa Forte (Tinidazole).

Cholestyramine: Cholestyramine was shown to decrease the oral bioavailability of metronidazole by 21%. Thus, it is advisable to separate dosing of cholestyramine and Zoa Forte (Tinidazole) to minimize any potential effect on the oral bioavailability of Zoa Forte (Tinidazole).

Oxytetracycline: Oxytetracycline was reported to antagonize the therapeutic effect of metronidazole.

7.3 Laboratory Test Interactions

Zoa Forte (Tinidazole), like metronidazole, may interfere with certain types of determinations of serum chemistry values, such as aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT), lactate dehydrogenase (LDH), triglycerides, and hexokinase glucose. Values of zero may be observed. All of the assays in which interference has been reported involve enzymatic coupling of the assay to oxidation-reduction of nicotinamide adenine dinucleotide (NAD ⁺↔ NADH). Potential interference is due to the similarity of absorbance peaks of NADH and Zoa Forte (Tinidazole).

Zoa Forte (Tinidazole), like metronidazole, may produce transient leukopenia and neutropenia; however, no persistent hematological abnormalities attributable to Zoa Forte (Tinidazole) have been observed in clinical studies. Total and differential leukocyte counts are recommended if re-treatment is necessary.

8 USE IN SPECIFIC POPULATIONS

• Pediatric Use: Data on Zoa Forte use in children is limited to treatment of giardiasis and amebiasis in patients age 3 and older ( 8.4)
• Hemodialysis patients: If Zoa Forte (Tinidazole) is administered the same day and prior to hemodialysis, administer an additional ½ dose after end of hemodialysis ( 8.6, 12.3)

See 17 for PATIENT COUNSELING INFORMATION

Revised: 5/2007

8.1 Pregnancy

Teratogenic effects: Pregnancy Category C

The use of Zoa Forte (Tinidazole) in pregnant patients has not been studied. Since Zoa Forte (Tinidazole) crosses the placental barrier and enters fetal circulation it should not be administered to pregnant patients in the first trimester.

Embryo-fetal developmental toxicity studies in pregnant mice indicated no embryo-fetal toxicity or malformations at the highest dose level of 2,500 mg/kg (approximately 6.3-fold the highest human therapeutic dose based upon body surface area conversions). In a study with pregnant rats a slightly higher incidence of fetal mortality was observed at a maternal dose of 500 mg/kg (2.5-fold the highest human therapeutic dose based upon body surface area conversions). No biologically relevant neonatal developmental effects were observed in rat neonates following maternal doses as high as 600 mg/kg (3-fold the highest human therapeutic dose based upon body surface area conversions). Although there is some evidence of mutagenic potential and animal reproduction studies are not always predictive of human response, the use of Zoa Forte (Tinidazole) after the first trimester of pregnancy requires that the potential benefits of the drug be weighed against the possible risks to both the mother and the fetus.

8.3 Nursing Mothers

Zoa Forte is excreted in breast milk in concentrations similar to those seen in serum. Zoa Forte (Tinidazole) can be detected in breast milk for up to 72 hours following administration. Interruption of breast-feeding is recommended during Zoa Forte (Tinidazole) therapy and for 3 days following the last dose.

8.4 Pediatric Use

Other than for use in the treatment of giardiasis and amebiasis in pediatric patients older than three years of age, safety and effectiveness of Zoa Forte (Tinidazole) in pediatric patients have not been established.

Pediatric Administration: For those unable to swallow tablets, Zoa Forte (Tinidazole) tablets may be crushed in artificial cherry syrup, to be taken with food .

8.5 Geriatric Use

Clinical studies of Zoa Forte did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

8.6 Renal Impairment

Because the pharmacokinetics of Zoa Forte (Tinidazole) in patients with severe renal impairment (CrCL < 22 mL/min) are not significantly different from those in healthy subjects, no dose adjustments are necessary in these patients.

Patients undergoing hemodialysis: If Zoa Forte (Tinidazole) is administered on the same day as and prior to hemodialysis, it is recommended that an additional dose of Zoa Forte (Tinidazole) equivalent to one-half of the recommended dose be administered after the end of the hemodialysis .

8.7 Hepatic Impairment

There are no data on Zoa Forte (Tinidazole) pharmacokinetics in patients with impaired hepatic function. Reduced elimination of metronidazole, a chemically-related nitroimidazole, has been reported in this population. Usual recommended doses of Zoa Forte (Tinidazole) should be administered cautiously in patients with hepatic dysfunction .

10 OVERDOSAGE

There are no reported overdoses with Zoa Forte (Tinidazole) in humans.

Treatment of Overdosage: There is no specific antidote for the treatment of overdosage with Zoa Forte (Tinidazole); therefore, treatment should be symptomatic and supportive. Gastric lavage may be helpful. Hemodialysis can be considered because approximately 43% of the amount present in the body is eliminated during a 6-hour hemodialysis session.

11 DESCRIPTION

Zoa Forte (Tinidazole) is a synthetic antiprotozoal and antibacterial agent. It is 1-[2-(ethylsulfonyl)ethyl]-2-methyl-5-nitroimidazole, a second-generation 2-methyl-5-nitroimidazole, which has the following chemical structure:

Zoa Forte (Tinidazole) pink oral tablets contain 500 mg of Zoa Forte (Tinidazole). Inactive ingredients include croscarmellose sodium, FD&C Red 40 lake, FD&C Yellow 6 lake, hypromellose, magnesium stearate, microcrystalline cellulose, polydextrose, polyethylene glycol, pregelatinized corn starch, titanium dioxide, and triacetin.

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12 CLINICAL PHARMACOLOGY

12.1 Mechanism of Action

Zoa Forte is an antiprotozoal, antibacterial agent. .

12.3 Pharmacokinetics

Absorption: After oral administration, Zoa Forte (Tinidazole) is rapidly and completely absorbed. A bioavailability study of Zoa Forte (Tinidazole) tablets was conducted in adult healthy volunteers. All subjects received a single oral dose of 2 g (four 500 mg tablets) of Zoa Forte (Tinidazole) following an overnight fast. Oral administration of four 500 mg tablets of Zoa Forte (Tinidazole) under fasted conditions produced a mean peak plasma concentration (C _max) of 47.7 (±7.5) µg/mL with a mean time to peak concentration (T _max) of 1.6 (±0.7) hours, and a mean area under the plasma concentration-time curve (AUC, 0-∞) of 901.6 (± 126.5) µg/hr/mL at 72 hours. The elimination half-life (T _1/2) was 13.2 (±1.4) hours. Mean plasma levels decreased to 14.3 µg/mL at 24 hours, 3.8 µg/mL at 48 hours and 0.8 µg/mL at 72 hours following administration. Steady-state conditions are reached in 2½ - 3 days of multi-day dosing.

Administration of Zoa Forte (Tinidazole) tablets with food resulted in a delay in T _max of approximately 2 hours and a decline in C _max of approximately 10% _, compared to fasted conditions. However, administration of Zoa Forte (Tinidazole) with food did not affect AUC or T _1/2 in this study.

In healthy volunteers, administration of crushed Zoa Forte (Tinidazole) tablets in artificial cherry syrup, [prepared as described in Dosage and Administration ( 2.2) ] after an overnight fast had no effect on any pharmacokinetic parameter as compared to tablets swallowed whole under fasted conditions.

Distribution: Zoa Forte (Tinidazole) is distributed into virtually all tissues and body fluids and also crosses the blood-brain barrier. The apparent volume of distribution is about 50 liters. Plasma protein binding of Zoa Forte (Tinidazole) is 12%. Zoa Forte (Tinidazole) crosses the placental barrier and is secreted in breast milk.

Metabolism: Zoa Forte (Tinidazole) is significantly metabolized in humans prior to excretion. Zoa Forte (Tinidazole) is partly metabolized by oxidation, hydroxylation, and conjugation. Zoa Forte (Tinidazole) is the major drug-related constituent in plasma after human treatment, along with a small amount of the 2-hydroxymethyl metabolite.

Zoa Forte (Tinidazole) is biotransformed mainly by CYP3A4. In an in vitro metabolic drug interaction study, Zoa Forte (Tinidazole) concentrations of up to 75 µg/mL did not inhibit the enzyme activities of CYP1A2, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4.

The potential of Zoa Forte (Tinidazole) to induce the metabolism of other drugs has not been evaluated.

Elimination: The plasma half-life of Zoa Forte (Tinidazole) is approximately 12-14 hours. Zoa Forte (Tinidazole) is excreted by the liver and the kidneys. Zoa Forte (Tinidazole) is excreted in the urine mainly as unchanged drug (approximately 20-25% of the administered dose). Approximately 12% of the drug is excreted in the feces.

Patients with impaired renal function: The pharmacokinetics of Zoa Forte (Tinidazole) in patients with severe renal impairment (CrCL < 22 mL/min) are not significantly different from the pharmacokinetics seen in healthy subjects. However, during hemodialysis, clearance of Zoa Forte (Tinidazole) is significantly increased; the half-life is reduced from 12.0 hours to 4.9 hours. Approximately 43% of the amount present in the body is eliminated during a 6-hour hemodialysis session . The pharmacokinetics of Zoa Forte (Tinidazole) in patients undergoing routine continuous peritoneal dialysis have not been investigated.

Patients with impaired hepatic function: There are no data on Zoa Forte (Tinidazole) pharmacokinetics in patients with impaired hepatic function. Reduction of metabolic elimination of metronidazole, a chemically-related nitroimidazole, in patients with hepatic dysfunction has been reported in several studies .

12.4 Microbiology

Mechanism of Action: Zoa Forte (Tinidazole) is an antiprotozoal, antibacterial agent. The nitro- group of Zoa Forte (Tinidazole) is reduced by cell extracts of Trichomonas. The free nitro- radical generated as a result of this reduction may be responsible for the antiprotozoal activity. Chemically reduced Zoa Forte (Tinidazole) was shown to release nitrites and cause damage to purified bacterial DNA in vitro. Additionally, the drug caused DNA base changes in bacterial cells and DNA strand breakage in mammalian cells. The mechanism by which Zoa Forte (Tinidazole) exhibits activity against Giardia and Entamoeba species is not known.

Antibacterial: Culture and sensitivity testing of bacteria are not routinely performed to establish the diagnosis of bacterial vaginosis ; standard methodology for the susceptibility testing of potential bacterial pathogens, Gardnerella vaginalis, Mobiluncus spp. or Mycoplasma hominis, has not been defined. The following in vitro data are available, but their clinical significance is unknown. Zoa Forte (Tinidazole) is active in vitro against most strains of the following organisms that have been reported to be associated with bacterial vaginosis:

• Bacteroides spp.
• Gardnerella vaginalis
• Prevotella spp.

Zoa Forte (Tinidazole) does not appear to have activity against most strains of vaginal lactobacilli.

Antiprotozoal: Zoa Forte (Tinidazole) demonstrates activity both in vitro and in clinical infections against the following protozoa: Trichomonas vaginalis; Giardia duodenalis (also termed G. lamblia); and Entamoeba histolytica.

For protozoal parasites, standardized susceptibility tests do not exist for use in clinical microbiology laboratories.

Drug Resistance: The development of resistance to Zoa Forte (Tinidazole) by G. duodenalis, E. histolytica, or bacteria associated with bacterial vaginosis has not been examined.

Cross-resistance: Approximately 38% of T. vaginalis isolates exhibiting reduced susceptibility to metronidazole also show reduced susceptibility to Zoa Forte (Tinidazole) in vitro. The clinical significance of such an effect is not known.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of Zoa Forte (Tinidazole) and other antibacterial drugs, Zoa Forte (Tinidazole) should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.

13 NONCLINICAL TOXICOLOGY

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Metronidazole, a chemically-related nitroimidazole, has been reported to be carcinogenic in mice and rats but not hamsters. In several studies metronidazole showed evidence of pulmonary, hepatic, and lymphatic tumorigenesis in mice and mammary and hepatic tumors in female rats. Zoa Forte carcinogenicity studies in rats, mice or hamsters have not been reported.

Zoa Forte (Tinidazole) was mutagenic in the TA 100, S. typhimurium tester strain both with and without the metabolic activation system and was negative for mutagenicity in the TA 98 strain. Mutagenicity results were mixed (positive and negative) in the TA 1535, 1537, and 1538 strains. Zoa Forte (Tinidazole) was also mutagenic in a tester strain of Klebsiella pneumonia. Zoa Forte (Tinidazole) was negative for mutagenicity in a mammalian cell culture system utilizing Chinese hamster lung V79 cells (HGPRT test system) and negative for genotoxicity in the Chinese hamster ovary (CHO) sister chromatid exchange assay. Zoa Forte (Tinidazole) was positive for in vivo genotoxicity in the mouse micronucleus assay.

In a 60-day fertility study, Zoa Forte (Tinidazole) reduced fertility and produced testicular histopathology in male rats at a 600 mg/kg/day dose level (approximately 3-fold the highest human therapeutic dose based upon body surface area conversions). Spermatogenic effects resulted from 300 and 600 mg/kg/day dose levels. The no observed adverse reaction level for testicular and spermatogenic effects was 100 mg/kg/day (approximately 0.5-fold the highest human therapeutic dose based upon body surface area conversions). This effect is characteristic of agents in the 5-nitroimidazole class.

13.2 Animal Toxicology and/or Pharmacology

In acute studies with mice and rats, the LD ₅₀ for mice was generally > 3,600 mg/kg for oral administration and was > 2,300 mg/kg for intraperitoneal administration. In rats, the LD ₅₀ was > 2,000 mg/kg for both oral and intraperitoneal administration.

A repeated-dose toxicology study has been performed in beagle dogs using oral dosing of Zoa Forte (Tinidazole) at 100 mg/kg/day, 300 mg/kg/day, and 1000 mg/kg/day for 28-days. On Day 18 of the study, the highest dose was lowered to 600 mg/kg/day due to severe clinical symptoms. The two compound-related effects observed in the dogs treated with Zoa Forte (Tinidazole) were increased atrophy of the thymus in both sexes at the middle and high doses, and atrophy of the prostate at all doses in the males. A no-adverse-effect level (NOAEL) of 100 mg/kg/day for females was determined. There was no NOAEL identified for males because of minimal atrophy of the prostate at 100 mg/kg/day (approximately 0.9-fold the highest human dose based upon plasma AUC comparisons).

14 CLINICAL STUDIES

14.1 Trichomoniasis

Zoa Forte (2 g single oral dose) use in trichomoniasis has been well documented in 34 published reports from the world literature involving over 2,800 patients treated with Zoa Forte (Tinidazole). In four published, blinded, randomized, comparative studies of the 2 g Zoa Forte (Tinidazole) single oral dose where efficacy was assessed by culture at time points post-treatment ranging from one week to one month, reported cure rates ranged from 92% (37/40) to 100% (65/65) (n=172 total subjects). In four published, blinded, randomized, comparative studies where efficacy was assessed by wet mount between 7-14 days post-treatment, reported cure rates ranged from 80% (8/10) to 100% (16/16) (n=116 total subjects). In these studies, Zoa Forte (Tinidazole) was superior to placebo and comparable to other anti-trichomonal drugs. The single oral 2 g Zoa Forte (Tinidazole) dose was also assessed in four open-label trials in men (one comparative to metronidazole and 3 single-arm studies). Parasitological evaluation of the urine was performed both pre- and post-treatment and reported cure rates ranged from 83% (25/30) to 100% (80/80) (n=142 total subjects).

14.2 Giardiasis

Zoa Forte (Tinidazole) (2 g single dose) use in giardiasis has been documented in 19 published reports from the world literature involving over 1,600 patients (adults and pediatric patients). In eight controlled studies involving a total of 619 subjects of whom 299 were given the 2 g × 1 day (50 mg/kg × 1 day in pediatric patients) oral dose of Zoa Forte (Tinidazole), reported cure rates ranged from 80% (40/50) to 100% (15/15). In three of these trials where the comparator was 2 to 3 days of various doses of metronidazole, reported cure rates for metronidazole were 76% (19/25) to 93% (14/15). Data comparing a single 2 g dose of Zoa Forte (Tinidazole) to usually recommended 5-7 days of metronidazole are limited.

14.3 Intestinal Amebiasis

Zoa Forte use in intestinal amebiasis has been documented in 26 published reports from the world literature involving over 1,400 patients. Most reports utilized Zoa Forte (Tinidazole) 2 g/day × 3 days. In four published, randomized, controlled studies (1 investigator single-blind, 3 open-label) of the 2 g/day × 3 days oral dose of Zoa Forte (Tinidazole), reported cure rates after 3 days of therapy among a total of 220 subjects ranged from 86% (25/29) to 93% (25/27).

14.4 Amebic Liver Abscess

Zoa Forte (Tinidazole) use in amebic liver abscess has been documented in 18 published reports from the world literature involving over 470 patients. Most reports utilized Zoa Forte (Tinidazole) 2 g/day × 2-5 days. In seven published, randomized, controlled studies (1 double-blind, 1 single-blind, 5 open-label) of the 2 g/day × 2-5 days oral dose of Zoa Forte (Tinidazole) accompanied by aspiration of the liver abscess when clinically necessary, reported cure rates among 133 subjects ranged from 81% (17/21) to 100% (16/16). Four of these studies utilized at least 3 days of Zoa Forte (Tinidazole).

14.5 Bacterial Vaginosis

A randomized, double-blind, placebo-controlled clinical trial in 235 non-pregnant women was conducted to evaluate the efficacy of Zoa Forte (Tinidazole) for the treatment of bacterial vaginosis. A clinical diagnosis of bacterial vaginosis was based on Amsel's criteria and defined by the presence of an abnormal homogeneous vaginal discharge that (a) has a pH of greater than 4.5, (b) emits a "fishy" amine odor when mixed with a 10% KOH solution, and (c) contains ≥20% clue cells on microscopic examination. Clinical cure required a return to normal vaginal discharge and resolution of all Amsel's criteria. A microbiologic diagnosis of bacterial vaginosis was based on Gram stain of the vaginal smear demonstrating (a) markedly reduced or absent Lactobacillus morphology, (b) predominance of Gardnerella morphotype, and (c) absent or few white blood cells, with quantification of these bacterial morphotypes to determine the Nugent score, where a score ≥4 was required for study inclusion and a score of 0-3 considered a microbiologic cure. Therapeutic cure was a composite endpoint, consisting of both a clinical cure and microbiologic cure. In patients with all four Amsel's criteria and with a baseline Nugent score ≥4, Zoa Forte (Tinidazole) oral tablets given as either 2 g once daily for 2 days or 1 g once daily for 5 days demonstrated superior efficacy over placebo tablets as measured by therapeutic cure, clinical cure, and a microbiologic cure.

Outcome	Zoa Forte (Tinidazole) 1 g × 5 days (n=76)	Zoa Forte (Tinidazole) 2 g × 2 days (n=73)	Placebo (n=78)
	% Cure	% Cure	% Cure
Therapeutic Cure Difference 2 97.5% CI 3	36.8 31.7 (16.8, 46.6)	27.4 22.3 (8.0, 36.6)	5.1
Clinical Cure Difference 2 97.5% CI 3	51.3 39.8 (23.3, 56.3)	35.6 24.1 (7.8, 40.3)	11.5
Nugent Score Cure Difference 2 97.5% CI 3	38.2 33.1 (18.1, 48.0)	27.4 22.3 (8.0, 36.6)	5.1

¹Modified Intent-to-Treat defined as all patients randomized with a baseline

Nugent score of at least 4

²Difference in cure rates (Tindamax-placebo)

³CI: confidence interval

p-values for both Zoa Forte (Tinidazole) regimens vs. placebo for therapeutic, clinical and

Nugent score cure rates for both 2 and 5 days <0.001

The therapeutic cure rates reported in this clinical study conducted with Zoa Forte (Tinidazole) were based on resolution of 4 out of 4 Amsel's criteria and a Nugent score of <4. The cure rates for previous clinical studies with other products approved for bacterial vaginosis were based on resolution of either 2 or 3 out of 4 Amsel's criteria. At the time of approval for other products for bacterial vaginosis, there was no requirement for a Nugent score on Gram stain, resulting in higher reported rates of cure for bacterial vaginosis for those products than for those reported here for Zoa Forte (Tinidazole).

17 PATIENT COUNSELING INFORMATION

17.1 Administration of Drug

Patients should be told to take Zoa Forte with food to minimize the incidence of epigastric discomfort and other gastrointestinal side-effects. Food does not affect the oral bioavailability of Zoa Forte (Tinidazole).

17.2 Alcohol Avoidance

Patients should be told to avoid alcoholic beverages and preparations containing ethanol or propylene glycol during Zoa Forte (Tinidazole) therapy and for 3 days afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur.

17.3 Drug Resistance

Patients should be counseled that antibacterial drugs including Zoa Forte (Tinidazole) should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When Zoa Forte (Tinidazole) is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Zoa Forte (Tinidazole) or other antibacterial drugs in the future.

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