ed studies of topical or oral oxybutynin use in pregnant women. Subcutaneous administration to rats at doses up to 25 mg/kg (approximately 50 times the human exposure based on surface area) and to rabbits at doses up to 0.4 mg/kg (approximately 1 times the human exposure) revealed no evidence of harm to the fetus due to oxybutynin chloride. The safety of GELNIQUE administration to women who are or who may become pregnant has not been established. Therefore, GELNIQUE should not be given to pregnant women unless, in the judgment of the physician, the probable clinical benefits outweigh the possible hazards.
8.3 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 GELNIQUE is administered to a nursing woman.
8.4 Pediatric Use
Safety and effectiveness of GELNIQUE in pediatric patients have not been established.
8.5 Geriatric Use
Of the 496 patients exposed to GELNIQUE in the randomized, double-blind, placebo-controlled 12-week study and the 14-week safety extension study, 188 patients (38%) were 65 years of age and older. No overall differences in safety or effectiveness were observed between these patients and younger patients, but greater sensitivity of some older individuals cannot be ruled out [see Clinical Pharmacology (12.3)].
8.6 Renal Impairment
There is no experience with the use of GELNIQUE in patients with renal impairment.
8.7 Hepatic Impairment
There is no experience with the use of GELNIQUE in patients with hepatic impairment.
10 OVERDOSAGE
Overdosage with oxybutynin has been associated with anticholinergic effects including central nervous system excitation, flushing, fever, dehydration, cardiac arrhythmia, vomiting, and urinary retention. Oral ingestion of 100 mg oxybutynin chloride in association with alcohol has been reported in a 13-year-old boy who experienced memory loss, and in 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 recovered fully with symptomatic treatment.
Plasma concentrations of oxybutynin begin to decline 24 hours after GELNIQUE application. If overexposure occurs, monitor patients until symptoms resolve.
11 DESCRIPTION
Oxybutynin is an antispasmodic, antimuscarinic agent. GELNIQUE (oxybutynin chloride) is a clear and colorless hydroalcoholic gel containing 100 mg oxybutynin chloride per gram of gel. GELNIQUE is available in a metered-dose pump that dispenses 30 metered 1 gram doses or in a 1 gram (1.14 mL) unit dose. Each dose contains 100 mg oxybutynin chloride. Oxybutynin is delivered as a racemate of R- and S- isomers. Chemically, oxybutynin chloride is d, l (racemic) 4-(Diethylamino)-2-butynyl (±)-α-phenylcyclohexaneglycolate hydrochloride.
The empirical formula of oxybutynin is C22H31NO3•HCl. Its structural formula is:
Oxybutynin chloride is a white powder with a molecular weight of 393.95.
Inactive ingredients in GELNIQUE are alcohol, USP; glycerin, USP; hydroxypropyl cellulose, NF; sodium hydroxide, NF; and purified water, USP.
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
Oxybutynin acts as a competitive antagonist of acetylcholine at postganglionic muscarinic receptors, resulting in relaxation o
