[Drug interactions in the prescriptions of patients before and after a heart infarct: results of the MONICA Augsburg heart infarct registry].

The prescriptions of 603 patients who had survived acute myocardial infarction (AMI) for at least one year and were registered from 1 Oct 84 to 31 Dec 86 in the Coronary Event Register of the MONICA project Augsburg were analyzed for the presence of drug-drug interactions with the aid of a computerized drug information system (SMA). Prior to AMI, 59% of patients were treated (average of 2 active substance per patient), 100% were treated on release from hospital (4.5 active substances), and 96% one year after AMI (5.8 active substances). Potential drug-drug interactions were found in 18% of patients before AMI, 65% on discharge from hospital, and 66% one year after AMI. While the potential frequency and severity of interactions are minor on average, prescriptions frequently contain several interactions. Calculations show that at least 5-6% of all prescriptions after AMI will produce interactions, so that drug safety for this high-risk patient group can be enhanced by a drug information system. Beta-blockers are the substance group most frequently involved in potential interactions in AMI patients.