Drug Groups

approved; investigational

Description

Naratriptan is a triptan drug used for the treatment of migraine headaches. It is a selective 5-hydroxytryptamine1 receptor subtype agonist.

Indication

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

Pharmacology

Naratriptan is a selective agonist of serotonin (5-hydroxytryptamine; 5-HT) type 1B and 1D receptors. It is structurally and pharmacologically related to other selective 5-HT1B/1D receptor agonist. Naratriptan has 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.

Toxicity

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

Affected Organisms

Biotransformation

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

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.

Half Life

5-8 hours

Protein Binding

28%-31% (over the concentration range of 50 to 1000 ng/mL)

Distribution

* 170 L

Clearance

* 6.6 mL/min/kg

References

External Links