Volume 12, Number 1Review ArticlesA Comparative Review of Oxybutynin Chloride Formulations: Pharmacokinetics and Therapeutic Efficacy in Overactive BladderTreatment UpdateMichael J KennellyAntimuscarinic agents remain the mainstay of treatment of overactive bladder. However, the utility of some of these agents is limited due to tolerability concerns, multiple daily dosage regimens, lack of formulary coverage, and high cost. This can lead to problems with long-term compliance and may preclude optimal management. Oxybutynin has been the most widely prescribed antimuscarinic agent for more than 30 years. To meet the needs of tolerability and compliance, oxybutynin has evolved from an immediate-release pill to a once-daily oral dose and is now available as a topical gel. This review compares the various oxybutynin formulations in terms of pharmacokinetics, efficacy, and tolerability issues.[Rev Urol. 2010;12(1):12-19 doi: 10.3909/riu0484]Overactive bladderUrge incontinenceOxybutyninN-desethyloxybutynin