Predisposing Factors Leading to Warfarin Toxicity

Abstract

Introduction: Warfarin is a commonly utilized anticoagulant in the management of thrombosis, either prevention or treatment, with bleeding problems as one of the major adverse effect because of its narrow therapeutic index.
 Objective: To determine the frequency of various factors leading to warfarin toxicity which was defined as patients presented with International Normalized Ratio (INR) greater than five.
 Setting: Department of Adult Cardiology at National Institute of Cardiovascular Diseases (NICVD), Karachi, Pakistan.
 Methodology: The study type is descriptive, cross sectional. All patients who fulfilled the inclusion criteria and visited Department of Adult Cardiology at NICVD, Karachi, Pakistan were included. After ethical approval and informed and written consent. The collected data was entered using IBM SPSS - 21, for variables that were continuous mean Standard Deviation was calculated and for variables that were categorical frequency percentage were calculated.
 Results: Total of 87 patients with warfarin toxicity were included. 52 patients (60%) were males & 35 (40%) were females with the mean age of 48.5287 ± 13.1386 years. The factors leading to warfarin toxicity were dietary non-compliance 19 patients (21.83%), drug non-compliance in 18 (20.68%), drug-drug interactions in 12 (13.79%), irregular follow up in 23 (26.39%) and deranged liver functions in 26 (29.88%) patients.
 Conclusion: Warfarin toxicity has multifactorial causes. Deranged liver functions and irregular follow up of patients accounted for the most prominent factors leading to warfarin toxicity.

The Frequency of Use of Warfarin-Interfering Drugs in Patients Suffering from Warfarin Toxicity Referred to the Emergency Department of Imam Reza Hospital, Mashhad

“…resulting in irreversible complications [10,11]. Warfarin toxicity can range from an elevated INR (international normalized ratio) without clinical symptoms to life-threatening bleeding [12,13]. The primary side effect of warfarin toxicity is bleeding, which depends on the dosage, treatment length, the patient's basic clinical condition, and the simultaneous use of other warfarin-interfering drugs [13,14].…”

“…Warfarin toxicity can range from an elevated INR (international normalized ratio) without clinical symptoms to life-threatening bleeding [12,13]. The primary side effect of warfarin toxicity is bleeding, which depends on the dosage, treatment length, the patient's basic clinical condition, and the simultaneous use of other warfarin-interfering drugs [13,14]. Studying the causes of this disease, according to the genetic, individual, environmental, food characteristics, and co-morbidities drugs that can be used in any region [15][16][17].…”