Clot prevention with a mechanical heart valve

Ask the doctor

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Q. I have a mechanical heart valve, so I'm taking warfarin. But the frequent blood tests and occasional dose changes are bothersome. When, if ever, will I be able to take one of the new blood thinners instead of warfarin? Off-label use of other drugs is not uncommon. Why isn't that an option in this case?

A. Your question is a good one, and it requires a two-part answer. When doctors prescribe drugs "off-label," that means they believe the drug will help you, even if it has not been FDA-approved specifically for your condition. Sometimes, subsequent research provides strong evidence to support a specific off-label use, which may lead to the drug's FDA approval for that condition. But sometimes, research shows the exact opposite: a medication that doctors assumed would be beneficial is, in fact, not helpful — and sometimes even harmful.