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Imitrex is the first of a new kind of medicine prescribed to treat migraines.

It works through serotonin receptors to cause constriction of blood vessels to the brain. This in turn stops a migraine in progress.

It is effective for up to 80 percent of people with these debilitating headaches.

Imitrex is available both as an injection for self-administration and as tablets.

Side Effects and Interactions

Imitrex has, in rare cases, caused spasm of a coronary artery or a change in heart rhythm. This dangerous reaction makes it wise for people with heart disease to avoid Imitrex.

The most common side effects include, for the injection, pain at the injection site; sensations of warmth, cold, tingling, pressure, or tightness; flushing; pressure or pain in the chest; drowsiness; dizziness; and fatigue.

Common reactions to Imitrex tablets include sensations of warmth, cold, tingling, or pressure; flushing; chest tightness; dizziness; weakness; stiff neck; and a bad taste in the mouth.

Report symptoms or suspected side effects to the physician promptly.

Severe allergic reactions to Imitrex are rare but dangerous. Symptoms such as breathing difficulty or wheezing with hives or itching may signal life-threatening anaphylactic shock and require immediate emergency treatment.

Imitrex should not be given at the same time as ergot-containing migraine medicine such as Cafergot, Ergostat or Wigraine.

As noted above, Imitrex is potentially very dangerous in combination with MAO inhibitors such as Eldepryl, Nardil or Parnate.

Check with your doctor and pharmacist to make sure Imitrex is safe in combination with any other drugs you take.

Special Precautions

Imitrex must not be taken at the same time as MAO inhibitor medications (Eldepryl, Nardil, Parnate). At least two weeks should go by between the last dose of an MAO inhibitor and the first dose of Imitrex.

Imitrex should not be taken within 24 hours of an ergotamine or ergot-type migraine medicine.

Imitrex is inappropriate for people who have had angina or a heart attack, or who have blockage in the coronary arteries.

People with uncontrolled high blood pressure should not take Imitrex. Because it could cause coronary blood vessel spasm, a life-threatening condition, it should never be injected intravenously. It may also raise blood pressure and should not be given to anyone with uncontrolled hypertension.

There is some controversy about how well it can be determined who has heart disease and therefore should not get Imitrex.

The diagnosis of migraine should be confirmed with care before this medication is administered, as it can be dangerous if given to people with other neurological problems.

This medication is inappropriate for basilar or hemiplegic migraine.

Taking the Medicine

Imitrex injection is given subcutaneously during a migraine. The first signs of relief may be noticeable within 10 minutes, but the full effect may take an hour to develop.

Maximum dose is two injections in 24 hours. At least one hour should go by before a second injection is given.

Imitrex tablets are given with water or other fluids. The tablet is effective at any stage of the migraine, although the manufacturer recommends it be taken as early as possible.

If the headache returns after two hours or more, another tablet may be taken.

The maximum 24-hour dose for healthy people is 300 mg; those with chronic conditions may need to observe a lower maximum dose.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
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