OXY-TDS (Oxytrol®; Watson Pharma, Corona, CA) offers a number of advantages over oral drug administration, including improved pharmacokinetics, enhanced adherence, and a lower incidence of anticholinergic side effects. OXY-TDS is a matrix-type system composed of 3 layers; the middle layer contains oxybutynin and a skin permeation enhancer called triacetin. Triacetin controls the rate of drug absorption through the stratum corneum by its physiochemical interaction with skin lipids. Once through the stratum corneum, oxybutynin enters the systemic circulation via small capillaries located in the dermis. The 39 cm2 patch containing 36 mg of oxybutynin delivers 3.9 mg of oxybutynin daily. Steady-state
Inhibitors,research,lifescience,medical plasma concentrations are maintained Inhibitors,research,lifescience,medical for approximately 96 hours, eliminating the peaks and troughs associated with oral OXY-IR and allowing for twice-weekly application.18 Bioequivalence has been demonstrated when applied to the abdomen, buttock, and thigh, enabling the patient to rotate sites and lower adverse site reactions. Patient adherence with prescribed therapy is affected by a number of factors, including pill burden, complexity of dosing schedule, memory lapses, and adverse events.19 In studies, patients have been shown to Inhibitors,research,lifescience,medical fail to take less
than 50% of their prescribed dose of medication,20 and adherence has been improved by less-frequent dosing intervals.21 OXY-TDS applied twice weekly has the potential to improve patient adherence, selleck chemical Lenalidomide especially in older polypharmacy patients. Transdermal delivery of oxybutynin results in a lower incidence of anticholinergic side effects by avoiding first-pass
Inhibitors,research,lifescience,medical gastrointestinal and hepatic metabolism associated with oral administration. Avoidance of first-pass metabolism dramatically reduces the amount of N-DEO present in the systemic circulation, resulting in improved tolerability, with reported dry mouth and constipation rates similar to placebo.22 Inhibitors,research,lifescience,medical The most common treatment-related systemic adverse events experienced with OXY-TDS in integrated phase III studies include dry mouth (7.0%), constipation (2.1%), dizziness (0.8%), dysuria (1.2%), nausea (2.1%), and abnormal vision (1.2%).22,23 The lower levels of N-DEO relative to parent drug have similarly been shown to have smaller declines in saliva output.18 The literature supports the efficacy of OXY-TDS in treating patients with OAB. In a randomized, placebo-controlled, AV-951 phase III trial, OXY-TDS significantly reduced the number of weekly incontinence episodes (median selleck bio change, −19.0 vs −14.5; P = .0165), 24-hour frequency of urination (mean change, −2.3 vs −1.7; P = .0457), and increased the mean volume voided (median change, 24 vs 6 mL; P = .0063).22 In a subsequent head-to-head, placebo-controlled trial comparing OXY-TDS to extended-release tolterodine, both medications were equally effective in reducing incontinence episodes and urinary frequency, and superior to placebo23 (Figure 1).