Safety profile of tolterodine as used in general practice in England: results of prescription-event monitoring.

ABSTRACT

BACKGROUND: Unstable bladder symptoms are a common problem in general practice. Drug therapy with anticholinergic drugs is frequently used in the management of this condition. However such drugs are associated with a high incidence of anticholinergic adverse effects. Tolterodine is a competitive anticholinergic agent, selective for the bladder as opposed to the salivary glands. OBJECTIVE: To monitor the safety of tolterodine as used in general practice patients in England for the treatment of urinary frequency, urgency and incontinence. DESIGN: Prospective observational cohort study. PATIENTS AND PARTICIPANTS: 14,526 patients [mean age 62.7 (SD 16.4) years; 68.6% female]. METHODS: Patients prescribed tolterodine in general practice, soon after the release of the drug in the UK, were followed up for a minimum of 6 months using the technique of prescription-event monitoring (PEM). RESULTS: The most common adverse events reported were dry mouth, headache, malaise, constipation, dyspepsia, nausea and vomiting and pain in abdomen. We identified some uncommon events as possible adverse drug reactions--notably hallucinations, tachycardia and palpitations. The prevalence of these events was compared with that in patient cohorts for other drugs on the PEM database. The age- and sex-adjusted relative risk of hallucinations on tolterodine compared with 10 drugs of other therapeutic classes, and with terodiline, another drug indicated for bladder instability, was 4.85 [95% confidence interval (CI) 2.72 to 8.66] and 1.25 (95% CI 0.62 to 2.53), respectively. There was no significant difference for tachycardia/palpitation in this comparison. CONCLUSIONS: Tolterodine is well tolerated in general practice at the recommended daily dose. Hallucinations, tachycardia and palpitations are infrequently associated with the drug.