Medical Edge Newspaper Column

No need to wean off warfarin, but weigh benefits and risks first

September 5, 2008
Dear Mayo Clinic:
Our doctor took my husband off warfarin cold turkey after a number of years. Is this harmful?  He's 89 years old and has had a couple of strokes in the past. Please advise.

Answer:
Warfarin is an anticoagulant, a type of medication also known as a "blood thinner." It reduces your blood's ability to clot and helps prevent harmful clots from forming in your blood vessels. Stopping warfarin in and of itself is not harmful. That is, you don't have to slowly taper off your dose of warfarin before you stop taking it completely to avoid side effects, as is the case with some medications.

However, it could be dangerous to stop taking warfarin if the benefit of taking the medication is greater than the risk of stopping it.

If your husband was taking warfarin to prevent an ischemic stroke — then, depending on his medical situation, the risk of another stroke without warfarin could be high. An ischemic stroke occurs when the arteries to the brain are narrowed or blocked, causing severely reduced blood flow (ischemia). This deprives the brain cells of oxygen and nutrients. An anticoagulant, such as warfarin, can help prevent blood clots that may block the arteries.

Doctors usually prescribe warfarin for stroke prevention if a patient has one or more of the following medical conditions:

Arial fibrillation — a disorder in which the upper two chambers of the heart beat irregularly
Severe cardiomyopathy — a condition that decreases the heart's ability to pump effectively
Severe mitral valve stenosis — a disorder in which the valve between the two chambers on the left side of your heart narrows and obstructs blood flow

Warfarin is also used for certain blood clotting disorders and for stroke prevention in people who have a mechanical heart valve.

But, warfarin has downsides, especially as people age. The medication brings with it the risk of serious or even fatal bleeding, especially if taken for long periods of time and in people who are older than 75. This may have been part of the reason your husband's physician decided to have him stop taking warfarin. Other medical concerns play a role, too. If a person on warfarin has gastrointestinal bleeding or ulcers, a prior brain hemorrhage, frequent falls or difficulty with walking or balance, then the risk of taking warfarin may outweigh the benefit.

The good news is that if your husband was taking it to prevent another stroke, warfarin isn't the only alternative. In fact, for people who don't have any of the medical conditions mentioned earlier, a daily dose of aspirin is usually the medication of choice for stroke prevention. Similar to warfarin, aspirin interferes with your blood's clotting action, and helps to prevent a stroke.

If your husband is not now taking a daily dose of aspirin, he should discuss aspirin therapy with his doctor. Some medical conditions can make taking aspirin dangerous, including bleeding disorders, asthma, stomach ulcers and heart failure. Also, if your husband is concerned about his potential for increased risk of stroke or another medical condition without warfarin, encourage him to talk to his doctor about prevention alternatives.

—Kelly Flemming, M.D., Neurology, Mayo Clinic, Rochester, Minn.