[Do generic drugs help control expenditure on hypertension? Apropos of a case]

Abstract

Objective: In this article we analyze the influence of generic drugs on pharmaceutical expenditure on hypertension from the payer's perspective (the public health service), by examining the most widely used drugs: angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARBs).

Methods: Based on billing data to the public health service from all the pharmacies in the Health Area of Malaga, we studied the utilization (containers and cost) of ACEi (generic drugs ACEi+G and brand name) and ARBs (brand name only) (subgroup C09 ATC index) from 1999 to 2002. The mean price (weighted according to sales) and the percentage of deviation of prescriptions from one group of drugs to another was also studied.

Results: The increase in consumption of packages in subgroup C09 was 20.79%; the increase was greater for ARBs (136%) and for ACEi+G (177%). The total amount spent during the study period increased by more than 42%. Expenditure on ACEis decreased by almost 7%, despite the increase in expenditure on ACEi+G, whereas expenditure on ARBs increased by more than 154%. The mean price of this subgroup, weighted according to sales, increased by nearly 18%. The mean weighted price of the generic drugs, captopril and enalapril, and that of the brand name, trandolapril, decreased. Notable among ARBs was the increase in mean price weighted according to sales of irbesartan (9%) and valsartan (16%).

Conclusions: The use of generic drugs has reduced expenditure on ACEi and the mean weighted price of the subgroup. However, the increased use of generic drugs has not produced the expected savings for the Department of Health. This could be due to deviation of prescription scores toward drugs not affected by substitution by the pharmacy.