4 Dangerous Holiday Food-Drug Interactions

Warfarin inhibits vitamin K epoxide reductase complex 1, which converts vitamin K epoxide to the active vitamin K reduced. Vitamin K is a necessary cofactor in the activation of several coagulation factors and of anticoagulation factors protein C and S. Blocking vitamin K activation leads to anticoagulation.

Here is a case report of a man who drank cranberry/apple juice and went from a therapeutic INR of 2-3 to 6.45. However, case reports do not establish causation and can have numerous confounders that make conclusions difficult. 

There has been 1 prospective trial that failed to show an association between cranberry and increased INR when patients consumed up to 240 mL (8oz) of cranberry juice per day. The authors argue that previous case reports were based on the consumption of large amounts of cranberry and that the patients in those case reports also had underlying conditions, leading to potential confounders. Perhaps the best advice to warfarin patients is to enjoy their cranberry dishes but to limit how much they consume.

In patients using these medications at the generally prescribed doses, dietary restrictions aren’t completely necessary; however, there have still been case reports of patients developing severe hypertension at these doses. Just as in the cranberry example, moderation is key – the package insert for rasagiline, for example, states that patients should avoid foods “very high…(eg, >150mg) in tyramine.”

References:

1. BMS Customer Connect. Foods with vitamin K. http://www.coumadin.bmscustomerconnect.com/servlet/servlet.FileDownload?file=00Pi000000bxvTFEAY. Published December 2016. Accessed December 14, 2018.
2. Coumadin [package insert]. Princeton, NJ: Bristol-Myers Squibb; 1954.
3. Ansell J, McDonough M, Zhao Y, Harmatz JS, Greenblatt DJ. The absence of an interaction between warfarin and cranberry juice: a randomized, double-blind trial. J Clin Pharmacol. 2009;49:824-830.
4. Food and Drug Administration. FDA Drug Safety Communication: FDA warns about serious risks and death when combining opioid pain or cough medicines with benzodiazepines; requires its strongest warning.  https://www.fda.gov/Drugs/DrugSafety/ucm518473.htm. Issued August 31, 2016. Accessed December 14, 2018.
5. American Addiction Centers. Booziest holidays: A look at alcohol consumption during the holidays. https://www.alcohol.org/guides/booziest-holidays/. Accessed December 14, 2018.
6. Cogswell ME, Mugavero K, Bowman BA, Frieden TR. Dietary sodium and cardiovascular disease risk – measurement matters. N Engl J Med. 2016;375:580-586.
7. Whelton PK, Appel LJ, Sacco RL, et al. Sodium, blood pressure, and cardiovascular disease: Further evidence supporting the American Heart Association sodium reduction recommendations. Circulation. 2012;126:2880-2889.
8. Zelapar [package insert]. Aliso Viejo, CA: Valeant; Revised 2008.
9. American Academy of Neurology. Treating Parkinson’s disease symptoms. American Academy of Neurology Web site. https://www.aan.com/siteassets/home-page/policy-and-guidelines/quality/quality-improvement/patient-handouts/13parkdiseasesdmtool_pg.pdf. Published 2014. Accessed December 14, 2018.
10. Azilect [package insert]. North Wales, PA: Teva Pharmaceuticals; 2006.