Assessing Evidence of Interaction Between Smoking and Warfarin

Determinants of oral anticoagulation control in new warfarin patients: analysis using data from Clinical Practice Research Datalink

“…Interestingly, the effect of smoking appears to diminish after patients give up smoking. Studies suggest that smoking may interact with warfarin, but the clinical evidence of this interaction remains inconclusive [33,53]. Based on this finding, smoking cessation counselling should be instituted prior to initiation of warfarin therapy.…”

“…Clinical variables: Body mass index (BMI), smoking history, alcohol consumption and substance abuse (non-alcohol) [17,18,32,33]. Comorbidities that are shown to worsen anticoagulation control, that are treated with medications that interact with warfarin or that are associated with chaotic lifestyle or poor adherence: acute respiratory infection, cancer, chronic liver disease, chronic kidney disease, chronic lung disease (COPD and asthma), hyperthyroidism, hypothyroidism, epilepsy, bipolar disorder, dementia, major depression, congestive heart failure, hyperlipidaemia, hypertension, diabetes, vascular disease (prior myocardial infarction, peripheral artery disease or aortic plaque), history of stroke, history of bleeding, chronic use of pain medication, osteoarthritis and rheumatoid arthritis [15][16][17][18][34][35][36][37][38][39].…”

Patient Case

“…3 The metabolism of warfarin is mediated through the hepatic cytochrome P450 system. Among the various P450 hepatic enzymes, CYP2D6, CYP3A4, CYP1A2, CYP2C9, CYP2E1, and CYP2A6 isoforms appear to have a significant role in hepatic drug metabolism.…”

Analysis of the first therapeutic-target-achieving time of warfarin therapy and associated factors in patients with pulmonary embolism

“…Polycyclic aromatic hydrocarbons produced by the incomplete combustion of cigarette smoke may induce the activities of hepatic microsomal enzymes, including cytochrome 1A1 (CYP1A1), cytochrome 1A2 (CYP1A2) and cytochrome 2E1 (CYP2E1), which increases the clearance rate of warfarin and mitigates its anticoagulant effects (35,36). To date, the effect of smoking on the first TTA time remains uncertain.…”