Active ingredient: Naratriptan - Brands, Medical Use, Clinical Data

Brands, Medical Use, Clinical Data

Drug Category

• Vasoconstrictor Agents
• Selective Serotonin Agonists

Dosage Forms

• Tablet (1 mg, 2.5 mg)

Brands / Synonyms

Amerge; Amerge

Indications

For the acute treatment of migraine attacks with or without aura in adults.

Pharmacology

Naratriptan is a selective 5-hydroxytryptamine receptor subtype agonist indicated for the acute treatment of migraine attacks with or without aura in adults. Naratriptan is not intended for the prophylactic therapy of migraine or for use in the management of hemiplegic or basilar migraine. Naratriptan is an agonist for a vascular 5-hydroxytryptamine receptor subtype (probably a member of the 5-HT_1D family) having only a weak affinity for 5-HT_1A, 5-HT_5A, and 5-HT₇ receptors and no significant affinity or pharmacological activity at 5-HT₂, 5-HT₃ or 5-HT₄ receptor subtypes or at alpha1-, alpha2-, or beta-adrenergic, dopamine1,; dopamine2; muscarinic, or benzodiazepine receptors. This action in humans correlates with the relief of migraine headache. In addition to causing vasoconstriction, experimental data from animal studies show that Naratriptan also activates 5-HT₁ receptors on peripheral terminals of the trigeminal nerve innervating cranial blood vessels, which may also contribute to the antimigrainous effect of Naratriptan in humans.

Mechanism of Action

Naratriptan binds with high affinity to human 5-HT_1B and 5-HT_1D receptors leading to cranial blood vessel constriction.

Absorption

Well absorbed (74% oral biovaility), absorption is rapid with peak plasma concentrations after 2-5 hours. The rate of absorption is slower during a migraine attack.

Toxicity

Symptoms of overdose include light-headedness, loss of coordination, tension in the neck, and tiredness.

Biotrnasformation / Drug Metabolism

Primarily hepatic. In vitro, naratriptan is metabolized by a wide range of cytochrome P450 isoenzymes into a number of inactive metabolites.

Contraindications

AMERGE Tablets should not be given to patients with history, symptoms, or signs of ischemic cardiac, cerebrovascular, or peripheral vascular syndromes. In addition, patients with other significant underlying cardiovascular diseases should not receive AMERGE Tablets. Ischemic cardiac syndromes include, but are not limited to, angina pectoris of any type (e. g., stable angina of effort and vasospastic forms of angina such as the Prinzmetal's variant), all forms of myocardial infarction, and silent myocardial ischemia. Cerebrovascular syndromes include, but are not limited to, strokes of any type as well as transient ischemic attacks. Peripheral vascular disease includes, but is not limited to, ischemic bowel disease.

Because AMERGE Tablets may increase blood pressure, they should not be given to patients with uncontrolled hypertension .

AMERGE Tablets are contraindicated in patients with severe renal impairment (creatinine clearance <15 mL/ min).

AMERGE Tablets are contraindicated in patients with severe hepatic impairment (Child-Pugh grade C).

AMERGE Tablets should not be administered to patients with hemiplegic or basilar migraine.

AMERGE Tablets should not be used within 24 hours of treatment with another 5-HT₁ agonist, an ergotamine-containing or ergot-type medication like dihydroergotamine or methysergide.

AMERGE Tablets are contraindicated in patients with hypersensitivity to naratriptan or any of the components.

Drug Interactions

Ergot-containing drugs have been reported to cause prolonged vasospastic reactions. Because there is a theoretical basis that these effects may be additive, use of ergotamine-containing or ergot-type medications (like dihydroergotamine or methysergide) and naratriptan within 24 hours is contraindicated.

The administration of naratriptan with other 5-HT₁ agonists has not been evaluated in migraine patients. Because their vasospastic effects may be additive, coadministration of naratriptan and other 5-HT₁ agonists within 24 hours of each other is not recommended.

Drug/ Laboratory Test Interactions

AMERGE Tablets are not known to interfere with commonly employed clinical laboratory tests.