CAUTION: Federal law prohibits dispensing without prescription.
About the Drug-
Naratriptan is an anti-Migraine agent similar to sumatriptan but with higher lipophilicity and a corresponding longer duration of action. In the US, naratriptan oral tablets are called Amerge®; in the UK, the trade name is Naramig. A nasal spray formulation is under review.
A potent agonist at serotonin 5-HT1 type B and type D receptors; has no significant affinity for other serotonin receptors or for adrenergic, dopaminergic, muscarinic, or benzodiazepine receptors; at least 2 explanations exist for how agonism at serotonin type 1B and 1D receptors alleviates Migraine: (a) vasoconstriction of intracranial blood vessels, (b) inhibition of release of pro-inflammatory neuropeptides from sensory nerve endings in the trigeminal system; naratriptan does not inhibit MAO or P450 enzymes.
Uses for the acute treatment of Migraine, with or without aura; it is not for patients with hemiplegic or basilar Migraine.
Higher lipophilicity and a corresponding longer duration of action than sumatriptan; naratriptan has a half-life of roughly 6 hours while sumatriptan has a half-life of roughly 2.5 hours; naratriptan oral bioavailability is approximately 70%; onset of clinical effect is within 1 hour; duration of clinical effect can range as long as 24 hours; during phase III, 68% of Migraine patients experienced relief within 4 hours after receiving 2.5 mg compared to roughly one-third of patients receiving placebo; naratriptan is metabolized by several P450 enzymes; renal clearance exceeds GFR indicating active tubular secretion; do not use in patients with ischemic cardiac, cerebrovascular, or peripheral vascular syndromes, or within 24-hrs of administration of ergot alkaloids or other 5-HT1 agonists.
Major Adverse Reactions:
Naratriptan may cause less cardiovascular events than sumatriptan; oral doses of 2.5 mg exhibit a side effect profile similar to placebo.
Usual Adult Dosage:
Single doses of 1 mg or 2.5 mg PO are recommended; a repeat dose can be administered, if necessary, after 4 hours; total dose per episode should not exceed 5 mg; there is no evidence that 5 mg doses provide greater effects than doses of 2.5 mg; do not use in patients with CrCl < 15 ml/min.
NDA was filed 12/4/96; final approval granted 2/10/98 (press release 2/11/98). Manufacturered by Cerenex Pharmaceuticals, division of Glaxo Wellcome. (800)‹334‹0089.