The efficacy, tolerability and safety profile of tolterodine in the treatment of overactive/unstable bladder

A substantial number of studies have now been carried out in which tolterod ine has been compared with placebo and with oxybutynin in the treatment of unstable bladder. The majority of double-blind studies have been conducted over relatively short periods of up to 12 weeks, but in several cases patie nts have been allowed to continue treatment with tolterodine on an open-lab el basis for up to a year. It has been found that, compared with placebo, t olterodine produces dose-related improvements in a range of urodynamic and micturition variables related to micturition frequency, urge, and urge inco ntinence. In terms of its clinically beneficial effects, tolterodine at a d ose of 2 mg bid is equivalent to oxybutynin at a dose of 5 mg bid or 5 mg t id. Tolterodine and oxybutynin, both having antimuscarinic actions, tend to produce a similar range of adverse effects. However, tolterodine possesses greater selectivity than that shown by oxybutynin for muscarinic receptors in the detrusor muscle over receptors located in salivary gland tissue; as a consequence, tolterodine produces less frequent and less severe adverse effects linked to the autonomic system than are seen with oxybutynin. Fewer patients require dose reductions to maintain tolerability, and fewer withd raw from treatment for reasons of tolerability when tolterodine is used tha n when treatment is with oxybutynin. It is concluded that, at a dose of 2 m g bid, tolterodine can be used to good therapeutic effect in the management of unstable bladder, and that its tolerability and adverse event profile i s generally favourable and superior to that of oxybutynin.