Pharmacy Times June 2009


Drug Interactions: Insights and Observations


Warfarin and Antibiotics: More Evidence of a Drug-Disease Interaction


John R. Horn, PharmD, FCCP and Philip D. Hansten, PharmD





1.     Horn JR and Hansten PD. Enhanced warfarin response and antibiotics. Pharmacy Times, June 2004, 70.

2.     Medscape Medical News, April 2009,, accessed on April 28, 2009.

3.     Beckey NP et al Retrospective evaluation of a potential interaction between azithromycin and warfarin in patients stabilized on warfarin. Pharmacotherapy. 2000;20:1055-9.

4.     McCall KL et al. Determination of the lack of a drug interaction between azithromycin and warfarin. Pharmacotherapy. 2004;24:188-94.

5.     Rao KB et al. Enhanced hypoprothrombinemia with warfarin due to azit. Ann Phrarmacother. 2004;38:982-5.

6.     Shrader SP et al. Azithromycin and warfarin interaction. Pharmacotherapy. 2004;24:945-9.

7.     Foster DR et al. Potential interaction between azithromycin and warfarin. Pharmacotherapy. 1999;9:902-8.

8.     Eschenauer G et al. Azithromycin-warfarin interaction: are we fishing with a red herring? Pharmacotherapy. 2005;25:630-1.

9.     Shakeri-Nejad K et al. Drug interaction during therapy with major groups of antimicrobial agents. Expert Opin Pharmacother. 2006;7:639-51.

10.  Schelleman H et al. Warfarin with fluoroquinolones, sulfonamides, or azole antifungals: interactions and the risk of hospitalization for gastrointestinal bleeding. Clin Pharmacol Ther. 2008;84:581-8.