The pharmacovigilance of tamsulosin: event data on 12 484 patients

Objective To determine drug effectiveness and adverse effects in a noninter ventional observational cohort study of over 10 000 patients treated with t amsulosin in general medical practice. Methods Using prescription-event monitoring, data were collected of all pre scriptions for tamsulosin issued nationally during June 1996 to January 199 8, For each patient entered into the cohort a computerized longitudinal rec ord of exposure was constructed. The outcome data, patient information and an opinion about the effectiveness of the drug were provided by the prescri ber, using a standard questionnaire sent 6 months after the initial prescri ption for tamsulosin, The incidence of each of almost 2000 events listed in the Drug Safety Research Unit computerized dictionary was calculated and s crutinized by medical assessors for possible adverse reactions, and any dif ference determined between the incidence of each event in the first month a nd subsequent months of exposure. All deaths were followed up to detect pos sibly drug-related causes, Results Event data were obtained on 12 484 patients, from the 52.9% of ques tionnaires returned and that contained valid event data, Tamsulosin was rep orted to have been effective in 7428 (78.3%) of the 9487 patients in whom t he general practitioners expressed an opinion about effectiveness. Suspecte d adverse drug reactions were reported in only 171 (1.4%) of the cohort, Di zziness, headache, malaise and hypotension were common to the reported adve rse reactions, reasons for stopping the drug and events of greatest inciden ce density, None of the 282 deaths that occurred in this elderly cohort wer e attributed to the drug. Conclusion This study suggests that tamsulosin has a highly acceptable bene fit-to-risk ratio. No untoward features not already mentioned in the prescr ibing guidance were identified.