Naratriptan

Naratriptan is a prescription drug used to treat migraine headache. Naratriptan belongs to a family of anti-migraine drugs called triptans. Other members of this family include almotriptan (Axert), eletriptan (Relpax), frovatriptan (Frova), and sumatriptan (Imitrex).

The U.S Food and Drug Administration approved naratriptan in February 1998.

Other Names
Naratriptan is marketed as Amerge by the GlaxoSmithKline company.

Uses
Naratriptan is specifically indicated for the acute treatment of migraine headache.

How is Taken
Naratriptan is available in 1 and 2.5 mg tablets.

Single doses of 1 and 2.5 mg of naratriptan taken by mouth with fluids are both effective for the acute treatment of migraines in adults.

If headaches return or if a person has only partial response, the dose may be repeated once after 4 hours, for a maximum dose of 5 mg within any 24-hour period.

How Works
Triptans like naratriptan act on blood vessels in the head, stimulating them to constrict (clamp down). They do this by binding to and activate 5-HT 1D/1B receptors, which are specific molecules that ordinarily interact with serotonin. Vasoconstriction relieves some symptoms of the migraine attack.

In addition, the activation of 5-HT1D/1B receptors on sensory nerve endings in the skull inhibits the release of inflammation-causing proteins, which also leads to reduction in migraine symptoms.

How the body affects naratriptan
Peak circulating levels are reached 2-4 hours post-dosing.

Naratriptan is metabolized by several liver enzymes into a number of inactive substances. The enzyme system in the liver is called CYP450.

Naratriptan is then eliminated mainly in the urine, with 50% of the original dose excreted in the urine as the parent drug and 30% as metabolites (breakdown products).

Side Effects
The most common side effects (occurring >2% of treated patients) attributable to naratriptan use are:


 * Paresthesias (tingling sensations)
 * Dizziness
 * Drowsiness
 * Malaise/fatigue
 * Pain or pressure in the throat/neck region

Risks

 * Deaths and/or serious heart-related issues have arisen in people taking naratriptan with a history of heart disease or stroke.


 * Because it causes blood vessels to clamp down, which could harm a developing fetus, the use of naratriptan is not advised in pregnant women. To prevent pregancy, women of childbearing potential need to use effective contraceptive measures while taking naratriptan.

Interactions
Triptans like naratriptan should NOT be used with the following drugs:


 * Selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs)


 * Ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide)


 * Other triptans

Research
Naratriptan was found to be effective for the treatment of acute migraines. One study shows it may successfully treat patients who poorly tolerate other triptans or have migraine headaches of longer duration.