Extreme Warfarin Intoxication Secondary to Possible Covert Drug Ingestion

Abstract

A young adult male patient presented with an excessively prolonged prothrombin time (>90 sec) following approximately two weeks of therapy with oral warfarin sodium, in doses between 2.5 and 5 mg/d. Repeated administration of vitamin K and fresh frozen plasma was required to reverse the anticoagulation and maintain a normalized prothrombin time. Serial warfarin plasma concentration measurements were used to interpret the apparently unusual prothrombin time response profile and to detect the possibility of covert drug ingestion.

Phytonadione Therapy in a Multiple‐Drug Overdose Involving Warfarin

“…Two patients were discharged taking oral vitamin K 10 mg/day. 8,11 The coagulopathy was controlled within 6 days in five of the six patients reviewed.…”

“…Acute ingestions of warfarin 45-2000 mg have been reported (Table 2). [6][7][8][9][10][11] Symptoms appeared within 24-72 hours. Gingival bleeding, 7 bruising, 7 epistaxis, 9 ecchymoses, 9 hematuria, 7, 9-11 hemoptysis, 11 hematemesis, 11 hematochezia, 9 melena, 11 uterine bleeding, 9 and abdominal pain 10,11 were reported.…”

“…One patient may have been taking his own warfarin while in the hospital, mistaking it for an analgesic. 11 This resulted in a prolonged elevated INR despite several units of fresh-frozen plasma and numerous doses of intravenous and oral phytonadione, with up to 70 mg/day of phytonadione given. Two patients were discharged taking oral vitamin K 10 mg/day.…”

Retrospective Study of the Characteristics of Anticoagulant-Type Rodenticide Poisoning in Hong Kong

“…Most of the superwarfarin poisoning cases reported in the literature presented with an obvious history of rodenticide exposure, either accidental (more common in children) or intentional (more common in adults); these patients often did not take a significant amount of rodenticides and had no or minimal clinical signs or symptoms of coagulopathy [3,4]. Occasionally, some patients had superwarfarin poisoning whose context of exposure remained unidentified, and a number of such occult poisoning cases with significant bleeding events have been reported [5][6][7][8][9][10][11][12]. Though Munchausen syndrome, homicide, and even drugs of abuse laced with superwarfarins have been subsequently identified as the cause in a few patients [5,6], the route and etiology of poisoning remained unidentified in a majority of these cases [7][8][9][10][11][12].…”

“…Occasionally, some patients had superwarfarin poisoning whose context of exposure remained unidentified, and a number of such occult poisoning cases with significant bleeding events have been reported [5][6][7][8][9][10][11][12]. Though Munchausen syndrome, homicide, and even drugs of abuse laced with superwarfarins have been subsequently identified as the cause in a few patients [5,6], the route and etiology of poisoning remained unidentified in a majority of these cases [7][8][9][10][11][12]. Early identification of superwarfarin poisoning is important.…”