Bronchospasm and cough as adverse reactions to the ACE inhibitors captopril, enalapril and lisinopril. A controlled retrospective cohort study.

1. We report a controlled retrospective cohort study of respiratory adverse reactions to ACE inhibitors. Bronchospasm and cough occurred at a higher rate in patients treated with ACE inhibitors, no links with sex, past history of bronchospasm, drug type or dose were found. 2. Cohorts of 1013 patients on angiotensin converting enzyme (ACE) inhibitors and 1017 patients on lipid lowering drugs (LLDs) were compared for the occurrence of new bronchospasm, relapse of previous bronchospasm, increase of current bronchospasm, and cough. 3. The prevalence of bronchospasm was 5.5% for patients on ACE inhibitors and 2.3% for patients on LLDs, P < 0.001. The relative risk of a bronchospasm adverse reaction for a patient on an ACE inhibitor compared with a patient on a LLD was 2.39, 95% confidence interval 1.47 to 3.90. 4. No ACE inhibitor specificity, or significant sex differences were found in the prevalence of bronchospasm or cough after correcting for bias implicit in the original cohorts. The bronchospastic reactions were not dose dependent. 5. The prevalence of a past history of bronchospasm in patients reporting ACE inhibitor-induced bronchospasm (16%) was not significantly different from the prevalence in patients on ACE inhibitors without an adverse reaction (13%), P = 0.447. 6. The prevalence of ACE inhibitor cohort cough was 12.3% and 2.7% in the patients on LLDs, P < 0.0001. Cough did not occur more commonly in patients on ACE inhibitors who had experienced any bronchospasm (28%) than in patients on LLDs with bronchospasm (27%).