Testosterone and Warfarin

Publication Date: 
By: Alere Staff

If you or someone you know is taking warfarin (or brand of warfarin such as Coumadin®), you probably already know there are many medications that interact with warfarin and need to be taken with caution. Some medications can decrease the drugs effectiveness while many others make it work ‘too well’ leading to an increased bleeding risk. Oxandrin® (oxandrolone) is a prescription medication used to treat people with low testosterone. Testosterone drugs are not sold over the counter so there should be no chance of accidentally buying this type of medication at your local pharmacy or food store.

Does this interact with Warfarin?

Oxandrin® (oxandrolone) can increase your risk of bleeding. A study by Savient Pharmacetuicals, who makes Oxandrin, found a significant interaction between warfarin and Oxandrin resulting in the need for an 80-85% reduction in the dose of warfarin to achieve the targeted effect when a patient was also prescribed Oxandrin. The study resulted an in immediate package insert change for the testosterone drug to be used with caution.1

You have an important role in avoiding a warfarin-testosterone interaction. It is important to make sure each of the doctors you visit know that you are taking warfarin.


  1. Physicians notified of interaction between synthetic testosterone and warfarin. Medscape. May 05, 2004.http://www.medscape.com/viewarticle/782955

COUMADIN is a trademark of Bristol-Myers Squibb Pharma Company. Alere is not affiliated or associated with Bristol-Myers Squibb Pharma Company or the COUMADIN trademark.

Oxandrin is a trademark of the Savient Pharmaceutical Company.