(HealthDay News) — Immediate or delayed differences in adverse event rates were seen after generic commercialization of 3 antihypertensive drugs, according to a study published online in Circulation: Cardiovascular Quality and Outcomes.
Jacinthe Leclerc, RN, from the Institut National de Santé Publique du Québec in Canada, and colleagues examined the impact of 3 generic angiotensin II receptor blockers’ commercialization on adverse events for 136,177 losartan, valsartan, and candesartan users (age ≥66 years). Rates of adverse events were calculated monthly, 24 months before, and 12 months after generic commercialization.
The researchers found that before and after generic commercialization, for all users, there was a monthly mean rate of 100 adverse events for 1000 angiotensin II receptor blockers users. The month of generic commercialization, there was an increase in the rates of adverse events among generic users of losartan, valsartan, and candesartan of 8, 11.7, and 14%, respectively (difference of proportions versus brand name, 7.5 [95% confidence interval, -0.9 to 15.9%], 17.1 [95% confidence interval, 9.9 to 24.3%], and 16.6% [95% confidence interval, 7.9 to 25.3%], respectively). At ≤one year after generic commercialization, the monthly trend of adverse events was affected for generic versus brand-name losartan users only (difference of proportions, 2%). Results were similar in sensitivity analyses.
“Risk and survival analysis studies controlling for several potential confounding factors are required to better characterize generic substitution,” the authors write.
Several authors disclosed financial ties to the pharmaceutical industry.