Pharmacoutilization of antihypertensive drugs: a model of analysis.

Objectives:To identify clinical and economic indicators of pharmacoutilization ofantihypertensive drugs. Patients and methods: 4614 subjects receiving a first prescription for amlodipine, atenolol, fosinopril, indapamide, or losartan were included in the study. All prescriptions filled during the study period from January 1, 1997 to December 31, 1998 were considered. A retrospective analysis was carried out on information recorded in the drug database. The percentage of patients continuing, discontinuing, and switching the initial treatment, duration of treatment, and doses used were calculated together with total costs. Results: A large proportion of patients (65.1%) discontinued the treatment. From the analysis of the mean daily dose taken by patients who continued the treatment, it was found that many subjects took a drug dosage which was below the therapeutic dose range, whereas the administration of doses above the therapeutic range occurred only occasionally. Continuation of treatment accounted for 48.1% of total costs, switching accounted for 20.8%, and discontinuation represented 31.1% of total expenditures. Conclusions: With adequate markers, helpful data can be collected for monitoring the quality of antihypertensive drug prescriptions and the rational usage of resources in the general practice setting.