Harvard Health Letter

By the way, doctor: How much Imitrex is too much?

Q. My doctor suggested switching to a low-dose antidepressant like Elavil to take prophylactically rather than taking too much Imitrex, but I don't remember what the "too much" cutoff amount is.

A. Sumatriptan (Imitrex) is one of the increasingly popular triptan drugs that people take for migraine headaches. The triptans both constrict vessels in the head and inhibit pain signals traveling to the brain. It's unclear which of these mechanisms is most important in stifling migraine pain.

In general, people aren't supposed to take sumatriptan more than four times a month, and the maximum dose per episode is 200 milligrams. The concern about overusing the triptans comes partly from the possibility that by repeatedly narrowing the blood vessels in the head and chest the drugs might increase stroke and heart attack risk. Although they tend to home in on cranial blood vessels, the triptans also manage to find receptors on the coronary arteries and, very occasionally, can cause chest pain that resembles angina. Yet large studies haven't shown an increase in the number of strokes or heart attacks among people taking the triptans, so the worry may be a bit theoretical.

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