Finasteride and tamsulosin used in benign prostatic hypertrophy: a review of the prescription-event monitoring data.

OBJECTIVE

To review the results of non-interventional observational cohort studies of 14 772 patients treated with finasteride and 12 484 patients treated with tamsulosin, both studies being of national proportions and undertaken in general medical practice in England.

METHODS

Both studies were undertaken by prescription-event monitoring (PEM), whereby the exposure data are derived from information provided in strict confidence by the Prescription Pricing Authority of the National Health Service. The outcome data are derived from 'green form' questionnaires completed by the prescribing general practitioners (GPs). Additional data are obtained by medical follow-up with the attending practitioners. Adverse experience was measured in three ways; as reports of events which the doctors considered to represent adverse drug reactions; as reports of reasons for stopping the drug; and by studying the incidence density of each reported event. For these purposes a computerized dictionary containing 1430 higher level terms was used. The duration of exposure in the finasteride study was approximately 1 year and was approximately 6 months in the tamsulosin study.

RESULTS

The outcome data on the 14 772 and 12 484 patients treated in the finasteride and tamsulosin studies were derived from the 63% and 57.4% of the green forms sent out and returned, respectively. The finasteride cohort included two women and the tamsulosin cohort 70 women. The mean (SD) age of the men in the two cohorts was, respectively, 69.0 (9.2) and 66.2 (11.7) years. Both drugs were well tolerated on long-term therapy and 69.6% (10 274 patients) of the total finasteride and 62.0% (7739 patients) of the total tamsulosin cohort were still receiving the drug at the end of 6 months. In the finasteride study, impotence or ejaculatory failure was reported in 2.0% of the patients still receiving the drug; there were reports of decreased libido in 1.0% and gynaecomastia was reported whilst the drug was still being prescribed in 39 patients (0.3% of the cohort). With tamsulosin, uncommon cases of dizziness, headache, malaise and hypotension (89 reports in 12 484 patients, i.e. 0.7% of the cohort) were common to the findings of reported adverse reactions, reasons for stopping the drug and events of highest incidence density. None of the deaths which occurred in either of these large cohorts was attributed by either the reporting GPs or the PEM medical staff to the drugs examined. Conclusion The GPs rated the drugs effective in most patients; tolerance and adverse experience was consistent with the known pharmacology of the two drugs. No serious, unexpected adverse effects were identified.