Prevalence and management of drug interactions between nonsteroidal anti-inflammatory drugs and antithrombotics in ambulatory care.

Concomitant use of nonsteroidal anti-inflammatory drugs (NSAIDs) and antithrombotic agents is associated with increased risks of both bleeding and thromboembolism. In this prospective intervention study, community pharmacists screened for NSAID-antithrombotic interactions and contacted the prescribing physician to discuss interaction management. We included 782 interactions; these were found in an older, polymedicated patient population (mean age: 68 y, median of 5 other drugs). Ibuprofen (in 43.0% of cases) and low-dose aspirin (78.8%) were the most frequently involved NSAID and antithrombotic, respectively. Anticoagulants were involved in 16.1% of interaction cases. For 61% of cases, the interacting drugs were prescribed by the same physician. The pharmacist-physician discussion about how to manage the interaction mostly resulted in no change of pharmacotherapy (60.7%); the most frequent reason given by physicians was that the NSAID was for short-term use only. In 39.3% of cases the discussion resulted in a pharmacotherapy change; replacing the NSAID by paracetamol was the most common change.