Increased reporting of adverse reactions to ACE inhibitors associated withlimitations to drug reimbursement for anglotensin-II receptor antagonists

Background and aim: From February 1998 to September 1999, the Italian Minis try of Health limited angiotensin-II type-1 (AT(1)) receptor antagonist rei mbursement only to patients who necessitated discontinuation of angiotensin converting enzyme (ACE) inhibitor treatment due to cough or angioedema. We assessed the consequences of this decision on the reporting of ACE inhibit or-associated adverse drug reactions (ADRs). Methods: ACE inhibitor-associated ADRs reported to the national pharmacovig ilance system in 1997-2000 in the district of Varese (northern Italy, more than 820,000 inhabitants) were retrieved and analysed. The dispensation of ACE inhibitors and AT(1) receptor antagonists reimbursed by the National He alth System was also examined. Results: There were 228 reports of ACE inhibitor-associated ADRs, and cough was the ADR reported in 93.4% of cases. There were no reports of cough in 1997, 50 in 1998, 156 in 1999 and 7 in 2000. In 1998-1999, the dispensation of ACE inhibitors showed little variation, while that of AT(1) receptor an tagonists grew about twofold. Conclusions: There was a clear correlation between ACE inhibitor-associated ADR reporting and limitation to AT(1) receptor antagonist reimbursement st atus. Drug reimbursement policies should thus be added to the list of facto rs that may bias ADR reporting, and health authorities should be aware of t his potential bias when defining specific measures to regulate prescription and use of new drugs.