Influence of warfarin on symptoms of fatigue: findings of a randomized trial

Ann Pharmacother. 2005 May;39(5):840-2. doi: 10.1345/aph.1E531. Epub 2005 Mar 15.


Background: Some patients develop fatigue while taking warfarin, but causality is uncertain.

Objective: To assess whether warfarin use is associated with fatigue.

Methods: This investigation was a substudy of a randomized double-blind trial in 13 outpatient thromboembolism clinics. Subjects who had received one month of open-label warfarin therapy for venous thromboembolism due to a transient risk factor were randomly assigned to receive warfarin or placebo for 2 months and followed for another 9 months after stopping the study drug. Fatigue was measured using a Likert scale, and change of fatigue was measured by the patient's global rating.

Results: In 87 subjects, the overall ratings of fatigue were 0.1 unit lower (95% CI 0.6 units lower to 0.4 units higher) while taking warfarin. Global rating for change in fatigue intensity showed no increase of fatigue with warfarin use.

Conclusions: The short-term use of warfarin was not associated with symptoms of fatigue.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Analysis of Variance
  • Double-Blind Method
  • Fatigue / chemically induced*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Venous Thrombosis / drug therapy*
  • Warfarin / adverse effects*
  • Warfarin / therapeutic use


  • Warfarin