Probable acenocoumarol-amoxycillin interaction.
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.
Soto
J
J
Clinical Pharmacology Unit, Hospital Santa Cruz, Liencres-Cantabria, Spain.
Sacristan
J A
JA
Alsar
M J
MJ
Fernandez-Viadero
C
C
Verduga
R
R
D000074:Acenocoumarol / Q000008:administration & dosage / Q000009:adverse effects*; D000368:Aged; D000369:Aged, 80 and over; D000658:Amoxicillin / Q000009:adverse effects*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D011183:Postoperative Complications / Q000097:blood / Q000188:drug therapy; D012141:Respiratory Tract Infections / Q000097:blood / Q000188:drug therapy; D013924:Thrombophlebitis / Q000097:blood / Q000188:drug therapy; D013997:Time Factors
D000658:Amoxicillin; D000074:Acenocoumarol