Drug & Other Medications

It is important to take all your medication as directed by your doctor and when on warfarin medication sometimes taking over-the-counter medicines can have unwanted drug interaction.1

Some common over-the-counter medicines include pain relievers and cold medicines, but herbal supplements and vitamins are often overlooked. According to one study in The Journal of the American Medical Association, one in 25, or 2.2 million, older Americans are taking drug or supplement combinations that could place them at risk.2

Warfarin medication was identified as the prescription drug most likely to be associated with an increased risk of dangerous drug combinations or interactions.

PTINR.com® website reviews several medications, including prescription, over-the-counter and hermal supplements for potential interactions. As a general rule, assume that any over-the-counter products can influence your INR blood test result. You should always consult your doctor regarding the use of any over-the-counter medications or products.

  1. Bristol-Myers Squibb Company. Medication Guide for Coumadin Tablets and Coumadin for Injection [Package Insert]. 2007. Princeton, NJ: Bristol-Myers Squibb Company.
  2. Dima M. Qato, G. Caleb Alexander, Rena M. Conti, Michael Johnson, Phil Schumm, and Stacy Tessler Lindau. “Use of Prescription and Over-the-counter Medications and Dietary Supplements Among Older Adults in the United States”. JAMA, December 24/31, 2008; 300: 2867-2878.