General Information

Oxytrol (oxybutynin transdermal system), is a transdermal patch designed to deliver oxybutynin continuously and consistently over a 3- to 4-day interval after application to intact skin. Oxytrol is available as a 39 cm2 patch system containing 36 mg of oxybutynin. Oxytrol is indicated for the treatment of overactive bladder with symptoms of urge urinary incontinence, urgency, and frequency.

The dose of Oxytrol is one 3.9 mg/day system applied twice weekly (every 3 to 4 days).

Clinical Results

FDA approval of Oxytrol was based on the efficacy and safety evaluated in patients with urge/urinary incontinence in two phase III controlled studies and one open-label extension study.

Study 1 was a randomized, double blind, placebo-controlled study, comparing the safety and efficacy of Oxytrol at dose levels of 1.3, 2.6, and 3.9 mg/day to placebo in 520 subjects. Results showed that subjects experienced a significant reduction in weekly incontinence episodes, urinary frequency, and urinary void volume in active treatment groups versus placebo. An open-label, dose titration treatment extension allowed continued treatment for up to an additional 40 weeks for patients completing the double-blind period. All subjects had urge or mixed incontinence with incontinence episodes of at least 10 per week, and at least 8 micturitions per day.

Study 2 was a randomized, double blind, double-dummy trial comparing the safety and efficacy of Oxytrol 3.9 mg/day versus active and placebo controls in 361 subjects. All subjects had urge or mixed incontinence and had achieved a beneficial response from the anticholinergic treatment they were using at the time of study entry. Results showed a significant reduction in daily incontinence episodes, urinary frequency, and urinary void volume between placebo and active treatment groups.

Mechanism of Action

Oxybutynin is an antispasmodic, anticholinergic agent. The active ingredient is dissolved in the thin layer of adhesive that sticks the patch to the skin. Oxytrol delivers the medicine slowly and constantly through the skin and into the bloodstream for the 3 or 4 days that the patch is worn. Oxytrol's transdermal delivery system delivers 3.9 mg per day of oxybutynin consistently and continuously through the skin into the bloodstream, bypassing initial metabolism in the liver and the gastrointestinal tract that occurs with oral medications, providing relief of overactive bladder symptoms for up to four days.

Patients who have urinary retention, gastric retention, uncontrolled narrow-angle glaucoma or hypersensitivity to oxybutynin or other components of Oxytrol should not use Oxytrol.

Literature References

Birns J, Lukkari E, Malone-Lee JG et al. A randomized controlled trial comparing the efficacy of controlled-release oxybutynin tablets (10 mg once daily) with conventiona oxybutynin tablets (5 mg twice daily) in patients whose symptoms were stabilized on 5 mg twice daily oxybutynin. BJU International 2000;85:793-798.

Khoury JM. Urinary incontinence. No need to be wet and upset. NCMJ 2001 Mar/April;62(2):74-77.

Harvey MA, Baker K, Wells GA. Tolterodine versus oxybutynin in the treatment of urge urinary incontinence: a meta-analysis. Am J Obstet Gynecol 2001;185(1):56-61.

Cannon TW, Chancellor MB. Pharmacotherapy of the overactive bladder and advances in drug delivery. Clin Obstet Gynecol 2002 Mar;45(1):205-217.