Parenteral ketorolac and risk of myocardial infarction

PURPOSE: To examine the effects of ketorolac, a non-aspirin non-steroidal anti-inflammatory drug (NANSAID) with antiplatelet properties, on the risk of in-hospital myocardial infarction (MI). METHODS: A retrospective cohort study was performed among hospitalized patients given 10,219 courses of parenteral ketorolac and patients given 10,145 courses of parenteral opioids, without ketorolac, in 35 hospitals. Patients were matched by hospital, admitting service, and date of study drug initiation. Any MI documented in the chart that occurred during the drug course and up to 3 days after the last dose was recorded by trained abstractors. RESULTS: MI occurred in 18 (0.2%) ketorolac and 45 (0.4%) opioid courses (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.23-0.69). This negative association persisted in multivariable analysis adjusting for age, sex, history of diabetes mellitus or cardiovascular disease, and administration of antiplatelet agents (OR 0.42; 95% CI 0.24-0.73). The association also persisted in numerous analyses excluding patients who may have been treated with analgesics for ischemic pain, and when restricting events to those occurring while on the drug (OR 0.34; 95% CI 0.17-0.69). CONCLUSION: These results are consistent with a protective effect of ketorolac against MI. Future research that implements uniform screening for and independent validation of MIs as well as eliminates possible confounding by indication is the next logical step in confirming these findings.