IMITREX [Sumatriptan] is indicated in the use acute treatment of migraine.
Migraine, the most common cause of headache, afflicts approximately 15% of women and 6% of men. It is a vascular headache, comes in attacks
A useful definition of migraine is a benign and recurring syndrome of headache, nausea, vomiting, and/or other symptoms of neurologic dysfunction in varying admixtures. Migraine can often be recognized by its activators (Red wine, menses, hunger, lack of sleep, glare, estrogen, worry, perfumes, let-down periods) and its deactivators (sleep, pregnancy, exhilaration, triptans).
Severe headache attacks, regardless of cause, are more likely to be described as throbbing and associated with vomiting and scalp tenderness.
Milder headaches tend to be nondescript—tight, band like discomfort often involving the entire head—the profile of tension-type headache.
IMITREX [Sumatriptan] is a specific and selective 5-hydroxytriptamine1-like [5HT 1-like] receptor agonist with little or no effect at a variety of other receptor types.
It produces dose related constriction in the cerebral circulation. It does not bind to alpha adrenergic, beta adrenergic, muscarinic, dopaminergic or benzodiazepine receptors
Interest in the role of 5-HT a.k.a. serotonin in migraine has been renewed due to the introduction of the triptan class of anti-migraine drugs. The triptans are designed to stimulate selectively a particular subpopulation of 5-HT receptors. At least 14 specific 5-HT receptors exist in humans. The triptans are potent agonists of 5-HT1B, 5-HT1D, and 5- HT1F receptors and are less potent at 5-HT1A and 5-HT1E receptors. A growing body of data indicates that the anti-migraine efficacy of the triptans relates to their ability to stimulate 5-HT1B receptors, which are located on both blood vessels and nerve terminals. Selective 5-HT1D receptor agonists have, thus far, failed to demonstrate clinical efficacy in migraine. Triptans that are weak 5-HT1F agonists are also effective in migraine; however, only 5-HT1B efficacy is currently thought to be essential for anti migraine efficacy
The development of sumatriptan was the first experimentally based approach to identify and develop a novel therapy for migraine. In 1972, Humphrey and colleagues initiated a long term project aimed at identifying novel therapy for migraine. The goal of this project was to develop selective vasoconstrictors of the extracranial circulation. They focused on the identification of 5-HT receptors in the carotid vasculature, on which the theory of action of traditional anti-migraine drugs was based during the 1970s.
Sumatriptan, first synthesized in 1984, potently contracted the dog isolated saphenous vein which is believed to contain the novel 5-HT receptor located in the carotid circulation.
Sumatriptan was approved by the FDA in 1992.
Mechanism of action:
Before the onset of a migraine, the 5-HT/serotonin level in the brain becomes extremely low.
Sumatriptan is structurally similar to serotonin, and is a 5-HT agonist, which is one of the receptors to which serotonin binds. The specific receptor subtype it activates is present in the cranial and basilar arteries. Activation of these receptors causes vasoconstriction of those dilated arteries. Sumatriptan increases the 5-HT levels in the brain. Sumatriptan is also shown to decrease the activity of the trigeminal nerve, which probably accounts for sumatriptan's efficacy in treating cluster headaches. The injectable form of the drug has been shown to abort a cluster headache within fifteen minutes in 96% of cases. This type of headache is extremely painful and debilitating.
The peak plasma concentration of IMITREX [Sumatriptan] i.e. on subcutaneous injection is approximately 12 mins and its bioavailability is approximately 97%.
While on oral administration, the peak plasma concentration is 1 to 2 hours and bioavailability of only 14% to 17%.
Adverse effects and Contraindications:
Rare but serious cardiac effects have been associated with the administration of Sumatriptan, including coronary artery vasospasm, transient myocardial ischemia, atrial and ventricular arrhythmias, and myocardial infarction.
Most such events have occurred in patients with risk factors for coronary artery disease. In general, however only minor side effects are seen with sumatriptan in the acute treatment of migraine.
After subcutaneous injection of IMITREX [Sumatriptan], a majority of patients report transient mail pain, stinging, or burning sensation at the site of injection.
Other side effects are:
- Asthenia and fatigue
- Feelings of pressure
- Pain in neck, chest and jaw
IMITREX [Sumatriptan] is contraindicated in patients who have a history of ischemic or vasospastic coronary artery disease, cerebrovascular or peripheral vascular disease, or other significant cardiovascular diseases. This drug is also contraindicated in patients in patients with uncontrolled hypertension and in those patients who are on monoamine oxidase inhibitors.
It is not recommended for use in the pediatric age group and should not be used in the pregnant and lactating mothers.
IMITREX [Sumatriptan] is effective in the acute treatment of migraine, with or without aura. The treatment should begin as soon as possible after the onset of a migraine attack.
Approximately 70% of individuals report significant headache relief from a 6 mg subcutaneous dose of IMITREX [Sumatriptan]. This dose maybe repeated once within a 24-hour period if the headache doesn’t subside after the first dose of sumatriptan.
It should not be used concurrently with or within 24 hours of an ergot derivative nor should it be used with another triptan with 24 hours of each other.
IMITREX [Sumatriptan] is not useful for prophylaxis of migraine.
Samir is the author of
information located at
- Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 10th Edition, pgs 279-281
- Drug Today, July-September 2005 Edition, pg 432
- Pharmacology and Pharmacotherapeutics, R.S.Satoskar, S.D.Bhandarkar, S.S.Ainapure, Revised 17th Edition, pgs 618-619
- Harrison’s Principles of Internal Medicine, 16th Edition, pg 90-93