Pharmacy Author: Omudhome Ogbru, PharmD
Medical and Pharmacy Editor: Jay W. Marks, MD

GENERIC NAME: sumatriptan

BRAND NAME: Imitrex

DRUG CLASS AND MECHANISM: Sumatriptan is a drug that is used for treating migraine headaches. It belongs to a class of drugs called selective serotonin receptor agonists. Other members of this class include naratriptan (Amerge), zolmitriptan (Zomig), rizatriptan (Maxalt), frovatriptan (Frova), eletriptan (Relpax), and almotriptan (Axert). Migraine headaches are believed to result from dilatation of blood vessels in the brain. Sumatriptan relieves migraines by stimulating serotonin receptors in the brain which cause the muscles surrounding the blood vessels in the brain to contract and narrow the blood vessels. At the same time, it also reduces transmission of pain signals by nerves to the brain. While it is very effective in relieving migraine headaches, it does not prevent or reduce the number of headaches. The FDA approved sumatriptan in December 1992.

PRESCRIPTION: Yes

GENERIC AVAILABLE: Yes

PREPARATIONS: Tablets: 25, 50, 100 mg. Intranasal Solution: 5, 20 mg. Injection Solution: 4 and 6 mg/0.5 ml

STORAGE: Sumatriptan should be stored between 2-30 C (36-86 F).

PRESCRIBED FOR: All formulations of sumatriptan are used for acute treatment of migraine headaches with or without an aura in adults. The injectable formulation also is used for treating cluster headaches.

DOSING: The recommended oral dose is 25-100 mg and the maximum dose is 200 mg daily. The recommended intranasal dose is 5-20 mg and the maximum dose is 40 mg daily. The recommended injection dose is 4 or 6 mg injected under the skin. The maximum dose is two 6 mg injections separated by 1 hour.

DRUG INTERACTIONS: Monoamine oxidase inhibitors, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), and procarbazine (Matulane), may reduce the breakdown of sumatriptan in the liver, leading to increased blood levels and side effects of sumatriptan.

Combining sumatriptan with sibutramine (Meridia), selective serotonin reuptake inhibitors or SSRIs, including fluoxetine (Prozac), citalopram (Celexa), paroxetine (Paxil), and sertraline (Zoloft) or serotonin and norepinephrine reuptake inhibitors, including venlafaxine (Effexor), duloxetine (Cymbalta), and desvenlafaxine (Pristiq) may increase the concentration of serotonin in the brain, causing increased serotonin-related side effects.

Administering sumatriptan within 24 hours of treatment with an ergot-containing medication [dihydroergotamine (Migranal), ergotamine, Methergine) is contraindicated because such combinations increase the likelihood of vasospasms.

PREGNANCY: Safe use in pregnancy has not been established.

NURSING MOTHERS: Sumatriptan is excreted in breast milk. Infant exposure may be reduced by avoiding breast feeding for 12 hours after administration of sumatriptan.

SIDE EFFECTS: Side effects are generally transient. Some common side effects include pain or tightness in the chest or throat, tingling, flushing, weakness, dizziness, abdominal discomfort, sweating, nasal irritation, and injection site reactions. Rarely, allergic reactions have been reported, usually in individuals who are highly allergic to multiple allergens. Sumatriptan may elevate blood pressure in individuals with or without a history of high blood pressure. Individuals with uncontrolled high blood pressure should not use sumatriptan. Sumatriptan rarely has been associated with coronary artery spasm, heart attacks, stroke, abnormal heart beats, and seizures.

Reference: FDA Prescribing Information