Oxybutynin Drug Information

Adults

The recommended starting dose of Oxybutynin chloride extended-release tablets is 5 or 10 mg once daily at approximately the same time each day. Dosage may be adjusted in 5-mg increments to achieve a balance of efficacy and tolerability (up to a maximum of 30 mg/day). In general, dosage adjustment may proceed at approximately weekly intervals.

Pediatric Patients Aged 6 Years of Age and Older

The recommended starting dose of Oxybutynin chloride extended-release tablets is 5 mg once daily at approximately the same time each day. Dosage may be adjusted in 5-mg increments to achieve a balance of efficacy and tolerability (up to a maximum of 20 mg/day).

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, the 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 clinical practice. The safety and efficacy of Oxybutynin chloride extended-release tablets (5 to 30 mg/day) was evaluated in 774 adult subjects who participated in five double-blind, controlled clinical trials. In four of the five studies, Oxybutynin chloride IR (5 to 20 mg/day in 199 subjects) was an active comparator.

Adverse reactions reported by ≥ 1% of subjects are shown in Table 1. Table 1: Adverse Drug Reactions Reported by ≥ 1% of Oxybutynin chloride extended-release tablets-treated Adult Subjects in Five Double-blind, Controlled Clinical Trials of Oxybutynin chloride extended-release tablets System/Organ Class Preferred Term Oxybutynin chloride extended-release tablets 5 to 30 mg/day n = 774 % Oxybutynin chloride IR IR = immediate release 5 to 20 mg/day n = 199 % Psychiatric Disorders Insomnia 3.0

Nervous System Disorders Headache 7.5 8.0 Somnolence 5.6 14.1 Dizziness 5.0 16.6

Dysgeusia 1.6

Eye Disorders Vision blurred 4.3 9.6 Dry eye 3.1 2.5 Respiratory, Thoracic

and Mediastinal Disorders Cough 1.9

Oropharyngeal pain 1.9 1.5 Dry throat 1.7 2.5 Nasal dryness 1.7 4.5

Gastrointestinal Disorders Dry mouth 34.9

Constipation 8.7 15.1 Diarrhea 7.9 6.5 Dyspepsia 4.5 6.0 Nausea 4.5 11.6

Abdominal pain 1.6

Vomiting 1.3 1.5 Flatulence 1.2 2.5 Gastro-esophageal reflux disease 1.0 0.5 Skin

and Subcutaneous Tissue Disorders Dry skin 1.8

Pruritus 1.3 1.5 Renal and Urinary Disorders Dysuria 1.9 2.0 Urinary hesitation

1.9

Urinary retention 1.2 3.0 General Disorders and

Administration Site Conditions Fatigue 2.6

Investigations Residual urine volume

The bundled term residual urine volume consists of the preferred terms residual urine volume and residual urine volume increased. 2.3

The discontinuation rate due to adverse reactions was 4.4% with Oxybutynin chloride

extended-release tablets compared to 0% with Oxybutynin chloride IR. The most frequent adverse reaction causing discontinuation of study medication was dry mouth (0.7% ). The following adverse reactions were reported by <1% of Oxybutynin chloride extended-release tablets-treated patients and at a higher incidence than placebo in clinical trials: Metabolism and Nutrition Disorders: anorexia, fluid retention; Vascular disorders: hot flush; Respiratory, thoracic and mediastinal disorders: dysphonia; Gastrointestinal Disorders: dysphagia, frequent bowel movements; General disorders and administration site conditions: chest discomfort, thirst.

Postmarketing Experience

The following additional adverse reactions have been reported from worldwide postmarketing experience with Oxybutynin chloride extended-release tablets. Because postmarketing reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Infections and Infestations: Urinary tract infection; Psychiatric Disorders: psychotic disorder, agitation, confusional state, hallucinations, memory impairment; Nervous System Disorders: convulsions; Eye Disorders: glaucoma; Respiratory, Thoracic and Mediastinal Disorders: nasal congestion; Cardiac Disorders: arrhythmia, tachycardia, palpitations; QT interval prolongation; Vascular Disorders: flushing, hypertension; Skin and Subcutaneous Tissue Disorders: rash; Renal and Urinary Disorders: impotence;General Disorders and Administration Site Conditions: hypersensitivity reactions, including angioedema with airway obstruction, urticaria, and face edema; anaphylactic reactions requiring hospitalization for emergency treatment; Injury, poisoning and procedural complications: fall.

Additional adverse events reported with some other oxybutynin chloride formulations include: cycloplegia, mydriasis, and suppression of lactation. To report SUSPECTED ADVERSE REACTIONS contact AvKARE, Inc. at 1-855-361-3993; email [email protected] ; or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

The concomitant use of oxybutynin with other anticholinergic drugs or with other agents which produce dry mouth, constipation, somnolence (drowsiness), and/or other anticholinergic-like effects may increase the frequency and/or severity of such effects. Anticholinergic agents may potentially alter the absorption of some concomitantly administered drugs due to anticholinergic effects on gastrointestinal motility. This may be of concern for drugs with a narrow therapeutic index.

Anticholinergic agents may also antagonize the effects of prokinetic agents, such as metoclopramide. Mean oxybutynin chloride plasma concentrations were approximately 2 fold higher when Oxybutynin chloride extended-release tablets were administered with ketoconazole, a potent CYP3A4 inhibitor. Other inhibitors of the cytochrome P450 3A4 enzyme system, such as antimycotic agents (e.g., itraconazole and miconazole) or macrolide antibiotics (e.g., erythromycin and clarithromycin), may alter oxybutynin mean pharmacokinetic parameters (i.e., C max and AUC). The clinical relevance of such potential interactions is not known.

Caution should be used when such drugs are co-administered. Co-administration with other anticholinergic drugs may increase the frequency and/or severity of anticholinergic-like effects. Co-administration with strong cytochrome P450 (CYP) 3A4 inhibitors (e.g., ketoconazole) increases the systemic exposure of oxybutynin.

Pregnancy Pregnancy Category B. There are no adequate and well-controlled studies using Oxybutynin chloride extended-release tablets in pregnant women. Oxybutynin chloride extended-release tablets should be used during pregnancy only if the potential benefit to the patient outweighs the risk to the patient and fetus. Women who become pregnant during Oxybutynin chloride extended-release tablets treatment are encouraged to contact their physician.

Risk Summary Based on animal data, oxybutynin is predicted to have a low probability of increasing the risk of adverse developmental effects above background risk. Animal Data Reproduction studies with oxybutynin chloride in the mouse, rat, hamster, and rabbit showed no evidence of impaired fertility or harm to the animal fetus.

Pediatric Use The safety and efficacy of Oxybutynin chloride extended-release tablets were studied in 60 children in a 24-week, open-label, non-randomized trial. Patients were aged 6–15 years, all had symptoms of detrusor overactivity in association with a neurological condition (e.g., spina bifida), all used clean intermittent catheterization, and all were current users of oxybutynin chloride. Study results demonstrated that administration of Oxybutynin chloride extended-release tablets 5 to 20 mg/day was associated with an increase from baseline in mean urine volume per catheterization from 108 mL to 136 mL, an increase from baseline in mean urine volume after morning awakening from 148 mL to 189 mL, and an increase from baseline in the mean percentage of catheterizations without a leaking episode from 34% to 51%. Urodynamic results were consistent with clinical results.

Administration of Oxybutynin chloride extended-release tablets resulted in an increase from baseline in mean maximum cystometric capacity from 185 mL to 254 mL, a decrease from baseline in mean detrusor pressure at maximum cystometric capacity from 44 cm H 2 O to 33 cm H 2 O, and a reduction in the percentage of patients demonstrating uninhibited detrusor contractions (of at least 15 cm H 2 O) from 60% to 28%. The pharmacokinetics of Oxybutynin chloride extended-release tablets in these patients were consistent with those reported for adults. Oxybutynin chloride extended-release tablets are not recommended in pediatric patients who cannot swallow the tablet whole without chewing, dividing, or crushing, or in children under the age of 6.

Oxybutynin chloride extended-release tablets are contraindicated in patients with urinary retention, gastric retention and other severe decreased gastrointestinal motility conditions, uncontrolled narrow-angle glaucoma. Oxybutynin chloride extended-release tablets are also contraindicated in patients who have demonstrated hypersensitivity to the drug substance or other components of the product. There have been reports of hypersensitivity reactions, including anaphylaxis and angiodema.

Urinary retention Gastric Retention Uncontrolled narrow angle glaucoma Known hypersensitivity to Oxybutynin chloride extended-release tablets, oxybutynin or any component of Oxybutynin chloride extended-release tablets

The continuous release of oxybutynin from Oxybutynin chloride extended-release tablets should be considered in the treatment of overdosage. Patients should be monitored for at least 24 hours. Treatment should be symptomatic and supportive.

Activated charcoal as well as a cathartic may be administered. Overdosage with oxybutynin chloride has been associated with anticholinergic effects including central nervous system excitation, flushing, fever, dehydration, cardiac arrhythmia, vomiting, and urinary retention. Ingestion of 100 mg oxybutynin chloride in association with alcohol has been reported in a 13-year-old boy who experienced memory loss, and a 34-year-old woman who developed stupor, followed by disorientation and agitation on awakening, dilated pupils, dry skin, cardiac arrhythmia, and retention of urine.

Both patients fully recovered with symptomatic treatment.