Included as part of the PRECAUTIONS section.

Urinary Retention

Administer OXYTROL with caution in patients with clinically significant bladder outflow obstruction because of the risk of urinary retention.

Risks in Patients with Gastrointestinal Disorders

Administer OXYTROL with caution to patients with gastrointestinal obstructive disorders because of the risk of gastric retention.

OXYTROL, like other anticholinergic drugs, may decrease gastrointestinal motility and should be used with caution in patients with conditions such as ulcerative colitis or intestinal atony.

OXYTROL should be used with caution in patients who have gastroesophageal reflux and/or who are concurrently taking drugs (such as bisphosphonates) that can cause or exacerbate esophagitis.

Central Nervous System Effects

Products containing oxybutynin are associated with anticholinergic central nervous system (CNS) effects. A variety of CNS anticholinergic effects have been reported, including headache, dizziness, and somnolence. Patients should be monitored for signs of anticholinergic CNS effects, particularly after beginning treatment. Advise patients not to drive or operate heavy machinery until they know how OXYTROL affects them. If a patient experiences anticholinergic CNS effects, drug discontinuation should be considered.

Angioedema

Angioedema requiring hospitalization and emergency medical treatment has occurred with the first or subsequent doses of oral oxybutynin. In the event of angioedema, OXYTROL should be discontinued and appropriate therapy promptly provided.

Skin Hypersensitivity

Patients who develop skin hypersensitivity to OXYTROL should discontinue drug treatment.

Exacerbation of Symptoms of Myasthenia Gravis

Administer OXYTROL with caution to patients with myasthenia gravis, a disease characterized by decreased cholinergic activity at the neuromuscular junction.

Patient Counseling Information

See FDA-Approved Patient Labeling (Patient Information and Instructions for Use)

Instructions for Use

Inform patients that OXYTROL should be applied to dry, intact skin on the abdomen, hip, or buttock. A new application site should be selected with each new system to avoid re-application to the same site within 7 days. Inform patients that details on use of the system are explained in the PATIENT INFORMATION Leaflet.

Inform patients to discard used OXYTROL in household trash in a manner that prevents accidental application or ingestion by children, pets, or others. Inform patients to keep out of reach of children.

Important Anticholinergic Adverse Reactions

Patients should be informed that anticholinergic (antimuscarinic) agents, such as OXYTROL, may produce adverse reactions related to anticholinergic pharmacological activity including:

• Urinary retention and constipation.
• Heat prostration (due to decreased sweating) when anticholinergics such as OXYTROL are used in a hot environment.
• Dizziness or blurred vision. Patients should be advised to avoid driving or operating heavy machinery until OXYTROL's effects have been determined.
• Drowsiness that may be worsened by alcohol.
• Angioedema has been reported with oral oxybutynin use. Patients should be advised to promptly discontinue OXYTROL and seek immediate medical attention if they experience symptoms consistent with angioedema.

Nonclinical Toxicology

Carcinogenesis, Mutagenesis, Impairment of Fertility

A 24-month study in rats at dosages of oxybutynin chloride of 20, 80 and 160 mg/kg showed no evidence of carcinogenicity. These doses are approximately 6, 25 and 50 times the maximum exposure in humans taking an oral dose based on body surface area.

Oxybutynin chloride showed no increase of mutagenic activity when tested in Schizosaccharomyces pompholiciformis, Saccharomyces cerevisiae, and Salmonella typhimurium test systems. Reproduction studies with oxybutynin chloride in the mouse, rat, hamster, and rabbit showed no definite evidence of impaired fertility.

Use In Specific Populations

Pregnancy - Pregnancy Category B

There are no adequate and well-controlled studies using OXYTROL in pregnant women. OXYTROL 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 OXYTROL 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

In a rat embryo/fetal developmental toxicity study, pregnant rats received up to 25 mg/kg subcutaneously of oxybutynin chloride. Maternal systemic exposure was estimated to be 50 times that of women treated at the maximum recommended human dose (MRHD) of 36 mg, based on body surface area. No embryo/fetal toxicity was observed in rats under the conditions of this study.

In a rabbit embryo/fetal developmental toxicity study, pregnant rabbits received oxybutynin chloride at up to 0.4 mg/kg subcutaneously. Maternal systemic exposure was estimated to be about equal that of women treated at the MRHD of 36 mg, based on body surface area. No embryo/fetal toxicity was observed in rabbits under the conditions of this study.

In mouse and hamster embryo/fetal development studies, no embryo/fetal toxicity was observed.

Nursing Mothers

It is not known whether oxybutynin is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when OXYTROL is administered to a nursing woman.

Pediatric Use

The safety and efficacy of OXYTROL in pediatric patients have not been established.

Geriatric Use

Forty-nine percent of OXYTROL-treated patients in the clinical studies were at least 65 years of age. No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in response between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out [see CLINICAL PHARMACOLOGY].

Renal Impairment

The safety and efficacy of OXYTROL have not been established in patients with renal impairment.

Hepatic Impairment

The safety and efficacy of OXYTROL have not been established in patients with hepatic impairment.

Last reviewed on RxList: 10/18/2012
This monograph has been modified to include the generic and brand name in many instances.