Warfarin without Therapeutic Monitoring is a Rodenticide, but this Time it Kills the Patient: A Warfarin Toxicity Case Report

Hossein Karballaei  Mirzahosseini; Nioosha  Moradpour; Ehsan Yousefi  Mazhin; Atabak  Najafi; Amirmahdi  Mojtahedzadeh; Mojtaba  Mojtahedzadeh

doi:10.18502/aacc.v11i2.17972

Hossein Karballaei Mirzahosseini Department of Clinical Pharmacy, School of Pharmacy, Semnan University of Medical Science, Semnan, Iran.
Nioosha Moradpour Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
Ehsan Yousefi Mazhin Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
Atabak Najafi Department of Anesthesiology and Critical Care Medicine, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Amirmahdi Mojtahedzadeh Faculty of Medicine, Semmelweis University, Budapest, Hungary.
Mojtaba Mojtahedzadeh Department of Clinical Pharmacy, School of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.

DOI: https://doi.org/10.18502/aacc.v11i2.17972

Keywords: Warfarin toxicity; Aspirin; Intracerebral hemorrhage; Therapeutic monitoring

Abstract

According to the American Association of Poison Control Centers (AAPCC), 761 single exposures to the pharmaceutical warfarin were reported in 2021, accounting for more than 10 percent of anticoagulant cases. The cost and mortality caused by warfarin toxicity are very high and usually incurable and fatal. The most important action in the field of warfarin toxicity is to prevent its occurrence. To emphasize how warfarin toxicity occurs, a case is introduced in this regard. A 61-year-old man is found unconscious with a seizure on the street and transported to the hospital by Emergency Medical Services (EMS). In the emergency car, he received a diazepam injection for generalized seizures. His vital signs in the postictal state were as follows: blood pressure 82/44 mmHg, pulse rate 91 bpm, and oxygen saturation (SaO2) 93%. His past medical history includes an ischemic stroke and a myocardial infarction 12 years ago. He underwent Mitral valve repair 11 years ago and a mechanical-type Mitral valve replacement 2 years ago. After undergoing mitral valve replacement surgery, he continued taking warfarin and aspirin for 2 years without consulting a cardiologist or undergoing PT and INR tests. As a result, he suffered a massive intracerebral hemorrhage when his INR level rose above 6. It's important to note that he has no history of depression or suicide attempts. After experiencing decreased consciousness and seizures, he was quickly intubated. A brain CT scan revealed extensive evidence of intracerebral hemorrhage, and he was then transferred to the operating room for craniotomy. To manage the bleeding and because Prothrombin complex concentrate (PCC) was not available, the patient received two grams of fibrinogen, two units of Fresh Frozen Plasma (FFP), 10 mg of vitamin K, and one unit of Packed Red Blood Cells. Unfortunately, after a month-long stay in the ICU, the patient passed away as a result of Ventilator-associated pneumonia (VAP) and sepsis.