acenocoumarol and Respiratory-Tract-Infections

We present the case of a woman undergoing treatment with acenocoumarol for deep vein thrombosis, who maintained an international normalized ratio (INR) of between 2.5 and 4 for 2 months. Seven days after the introduction of amoxycillin (500 mg/8 h) for a probable respiratory infection, the patient developed spontaneous bruising, with an INR of 7.1. Treatment with amoxycillin was discontinued, and 3 weeks later the INR had returned to previous values. In this case, the increase in the INR value with associated bruising after the addition of amoxycillin suggests a drug interaction between acenocoumarol and amoxycillin, other possible causes having been eliminated.

Topics: Acenocoumarol; Aged; Aged, 80 and over; Amoxicillin; Drug Interactions; Drug Therapy, Combination; Female; Humans; Postoperative Complications; Respiratory Tract Infections; Thrombophlebitis; Time Factors