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treatment & management

Drug Profiles:
Amerge® (naratriptan)


CAUTION: Federal law prohibits dispensing without prescription.

 

About the Drug-

Second generation drawing board up anti-Migraine medicine. Amerge® is a much improved long acting Triptan. In fact it is the longest acting Triptan currently available. For patients achieving Migraine response with Amerge® 2.5mg, 72% to 81% experienced no recurrence within 24 hours.

Classification

  • Neurological Agents
  • Anti-Migraine Agents
  • pregnancy category C

Indications

  • headache
  • Migraine

Comments

Description:

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.

Actions:

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:

Uses for the acute treatment of Migraine, with or without aura; it is not for patients with hemiplegic or basilar Migraine.

Distinguishing Features:

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.

Status:

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.

References:

  • clinical study: Mathew NT et al. Neurology 1997;49:1485‹90.
  • clinical study: Klassen A et al. Headache 1997;37:640‹5.

 
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