Pharmacy Times – June 2010

Drug Interactions: Insights and Observations

Cranberry Juice and Warfarin: What More Have We Learned?

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


1. Horn JR, Hansten PD. Does cranberry juice increase the response to warfarin? Pharmacy Times. 2006;December:88.

2. Greenblatt DJ et al. Interaction of flurbiprofen with cranberry juice, grape juice, tea, and fluconazole: in vitro and clinical studies. Clin Pharmacol Ther. 2006;79:125.

3. Aston JL et al. Interaction between warfarin and cranberry juice. Pharmacotherapy. 2006;26:1314.

4. Mergenhagen KA et al. Elevated international normalized ratio after concurrent ingestion of cranberry sauce and warfarin. Am J Health Sys Pharm. 2008;65:2113.

5. Paeng CH et al. Interaction between warfarin and cranberry juice. Clin Ther. 2007;29:1730.

6. Committee on safety of medicines. Possible interaction between warfarin and cranberry juice. Curr Probl Pharmacovigil. 2003;29:8.

7. Gage BF et al. Use of pharmacogenetic and clinical factors to predict the therapeutic dose of warfarin. Clin Pharmacol Ther. 2008;84:326.

8. Ansell J et al. A randomized, double-blind trial of the interaction between cranberry juice and warfarin. J Thromb Thrombolysis. 2008;25:112.

9. Li Z et al. Cranberry does not affect prothrombin time in male subjects on warfarin. J Am Diet Assoc. 2006;106:2057.

10. Abdul M et al. Pharmacodynamic interaction of warfarin with cranberry but not with garlic in healthy subjects. Br J Pharmacol. 2008;154:1691.

11. Horn JR et al. Proposal for a new tool to evaluate drug interaction cases. Ann Pharmacother. 2007;41:674.