อันตรกิริยาต่อกันของยาที่เหนี่ยวนำให้ระดับยา warfarin เพิ่มขึ้น Drug Interaction Induced Warfarin Overdose

Abstract

Warfarin, an anticoagulant drug, is known to interact with various drugs.Many risk factors affecting warfarin therapy include increasing age, specificcomorbidities, food and nutritional status, hepatic and renal function, herbsand dietary supplements, compliance, etc. The efficacy of warfarin isevaluated by the international normalized ratio (INR) value. The target INRvalue depends on warfarin indications. For most warfarin indications(including atrial fibrillation; AF), the target INR is 2.0 - 3.0. Low INR leadsto thromboembolic events and ineffective treatment whereas high INRcauses high risk of bleeding, including intracranial hemorrhage, a seriouscomplication of warfarin therapy. We report a clinical case of druginteraction-induced warfarin overdose with supratherapeutic INR afterreceiving ciprofloxacin for recurrent urinary retention and warfarin for AFwith slow ventricular response. Strong evidences of drug interactionbetween warfarin and ciprofloxacin indicate a major level in severity.Keywords: warfarin, drug interaction, warfarin overdose, case report