Michel Martin C
Department of Medicine, University of Essen, Essen, Germany.
Drug Saf. 2002;25(12):867-76. doi: 10.2165/00002018-200225120-00004.
Oxybutynin is a muscarinic receptor antagonist, which has been available for a number of years in its original immediate-release (IR) formulation. While oxybutynin IR has proven effective for the treatment of overactive bladder, its extended use can be limited by adverse effects, particularly dry mouth. An extended-release (ER) formulation of oxybutynin based on the OROS system has recently become available, which allows once daily administration. In direct comparison to oxybutynin IR, oxybutynin ER has an increased oral bioavailability for the parent compound oxybutynin which is accompanied by a reduced bioavailability for the active metabolite N-desethyl-oxybutynin. The latter has been implicated in mediating a major part of the adverse effects of oxybutynin treatment. Two double-blind, placebo-controlled, randomised studies in patients with overactive bladder have demonstrated that oxybutynin ER has a similar efficacy as oxybutynin IR but with improved tolerability. This is in line with clinical pharmacological studies demonstrating a smaller impairment of saliva production with oxybutynin ER than with oxybutynin IR. Thus, the ER formulation of oxybutynin maintains the therapeutic benefits and concomitantly improves tolerability.
奥昔布宁是一种毒蕈碱受体拮抗剂，其最初的速释（IR）制剂已上市多年。虽然奥昔布宁IR已被证明对治疗膀胱过度活动症有效，但其长期使用可能会受到不良反应的限制，尤其是口干。基于渗透泵控释系统（OROS）的奥昔布宁缓释（ER）制剂最近已上市，允许每日给药一次。与奥昔布宁IR直接比较，奥昔布宁ER对于母体化合物奥昔布宁的口服生物利用度增加，同时活性代谢物N-去乙基奥昔布宁的生物利用度降低。后者被认为介导了奥昔布宁治疗的大部分不良反应。两项针对膀胱过度活动症患者的双盲、安慰剂对照、随机研究表明，奥昔布宁ER与奥昔布宁IR疗效相似，但耐受性更好。这与临床药理学研究一致，该研究表明奥昔布宁ER对唾液分泌的损害小于奥昔布宁IR。因此，奥昔布宁的ER制剂保持了治疗效果，同时提高了耐受性。
