Identifying patterns of adverse event reporting for four members of the angiotensin II receptor blockers class of drugs: revisiting the Weber effect.

Purpose: To evaluate the evidence for temporal reporting patterns, such as the Weber effect, in spontaneous post-marketing adverse event (AE) reports submitted to the Food and Drug Administration (FDA), for four members of the angiotensin II receptor blockers drug class (ARBs).

Methods: For losartan, valsartan, irbesartan, and candesartan, we evaluated temporal trends in reporting for the total number of AE reports, serious AE reports, and direct reports from consumers or health care providers (direct reports) to FDA. Reporting patterns were considered consistent with the Weber effect when the peak occurred 2 years after US marketing and the number of reports declined thereafter. We tabulated the number of reports by year since the first report. We adjusted the total number of reports, number of serious AE reports, and number of direct reports by the number of US dispensed prescriptions.

Results: There were no clear temporal reporting patterns for the total number of reports, direct reports, or serious AE reports. We observed a consistent trend for the adjusted number of direct and serious AE reports. The adjusted number was highest in the first year and continually decreased over time for all four ARBs. For the adjusted total number of reports, the decline was not constant over time.

Conclusion: A characteristic temporal pattern in the adjusted number of reports, in which the adjusted number was highest in the first year and declined thereafter, was identified. However, we did not observe a pattern consistent with the Weber effect for these four ARBs.