Transdermal oxybutynin: for overactive bladder.
Oxybutynin binds to the M(3) muscarinic receptors on the detrusor muscle of the bladder, preventing acetylcholinergic activation and relaxing the muscle. The transdermal system delivers oxybutynin over a 3- to 4-day period after application to intact skin. Peak plasma concentrations of oxybutynin and the major active metabolite, N-desethyloxybutynin, are reached 24 - 48 hours after a single application and therapeutic concentrations are maintained throughout the dosage interval. In a large, randomised, double-blind trial, transdermal oxybutynin 3.9 mg/day significantly decreased the median number of incontinence episodes per week compared with placebo (-19 vs -15, p = 0.0165) in patients with overactive bladder. In addition, the micturition frequency was reduced and average voided volume was increased by transdermal oxybutynin treatment. Significant reductions in incontinence episodes following transdermal oxybutynin treatment were also observed in two further studies and the clinical efficacy was similar to that of oral tolterodine or oral oxybutynin. Transdermal oxybutynin was well tolerated in clinical trials. Application site reactions were the most common adverse effect; however, the majority were mild to moderate in severity. Adverse events associated with anticholinergic drugs (e.g. dry mouth) were less frequently reported in patients treated with transdermal oxybutynin than in those receiving orally administered oxybutynin or tolterodine.
Bang
Lynne M
LM
Adis International Limited, Auckland, New Zealand. demail@adis.co.nz
Easthope
Stephanie E
SE
Perry
Caroline M
CM
D000279:Administration, Cutaneous; D000284:Administration, Oral; D000328:Adult; D000368:Aged; D001559:Benzhydryl Compounds / Q000493:pharmacokinetics; D003408:Cresols / Q000493:pharmacokinetics; D004311:Double-Blind Method; D005076:Exanthema / Q000139:chemically induced; D006801:Humans; D008333:Mandelic Acids / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics*; D008875:Middle Aged; D010665:Phenylpropanolamine; D013997:Time Factors; D000068737:Tolterodine Tartrate; D001745:Urinary Bladder Diseases / Q000188:drug therapy*; D014549:Urinary Incontinence / Q000188:drug therapy*; D014987:Xerostomia / Q000139:chemically induced
D001559:Benzhydryl Compounds; D003408:Cresols; D008333:Mandelic Acids; D010665:Phenylpropanolamine; D000068737:Tolterodine Tartrate; C032681:desethyloxybutynin; C005419:oxybutynin