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Increase in International Normalized Ratio After Smoking Cessation in a Patient Receiving Warfarin
Author(s) -
Evans Mark,
Lewis Geoffrey M.
Publication year - 2005
Publication title -
pharmacotherapy: the journal of human pharmacology and drug therapy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.227
H-Index - 109
eISSN - 1875-9114
pISSN - 0277-0008
DOI - 10.1592/phco.2005.25.11.1656
Subject(s) - warfarin , medicine , smoking cessation , emergency medicine , anesthesia , pediatrics , atrial fibrillation , pathology
A 58‐year‐old man who was taking warfarin at a stable dosage was admitted to the hospital with a diagnosis of bacterial meningitis. Although he had previously been a smoker, after this admission, he decided to give up smoking. He was continued on his previous warfarin maintenance dosage when discharged, and his international normalized ratio (INR) soon began to climb substantially. When questioned, the patient reported no diet or lifestyle changes other than his smoking cessation. The patient's INR was stabilized at a warfarin dosage 23% lower than the maintenance dosage before he stopped smoking. This case report illustrates the potential for an interaction between warfarin and cigarette smoking and further suggests that the effect could be significant if a patient starts or stops smoking during warfarin therapy.