Naratriptan

Naratriptan is a prescription medicine belonging to the triptan class, used for the acute treatment of migraine headaches with or without aura in adults. It is available as 2.5 mg tablets and is the active ingredient in the branded product Naramig, manufactured by GlaxoSmithKline. Generic naratriptan is also widely available from other manufacturers.

The Triptan Mechanism

Naratriptan works by selectively targeting serotonin receptors in the cranial blood vessels and trigeminal nerve endings that are activated during a migraine attack. This action reverses the vasodilation and neurogenic inflammation that produce the throbbing pain and associated symptoms characteristic of migraine. Unlike simple analgesics or anti-inflammatory medicines, naratriptan specifically addresses the underlying pathophysiology of migraine rather than merely masking pain.

Naratriptan's Pharmacological Profile

Among the available triptans, naratriptan is distinguished by its relatively long half-life of approximately six hours. This confers a more sustained duration of action and a lower rate of headache recurrence within 24 hours compared with faster-acting agents such as sumatriptan or zolmitriptan. The trade-off is a slower onset of effect - naratriptan typically begins to relieve migraine within two to four hours, rather than the one to two hours seen with sumatriptan. This profile makes naratriptan well suited to patients who experience slow-building migraines, those prone to early morning attacks, or those who have experienced unsatisfactory results with other triptans due to recurrence.

Naratriptan is generally associated with a favourable tolerability profile, with a lower incidence of chest sensations, flushing, and other triptan-class side effects compared with higher-potency triptans. It should not be used to prevent migraines and is prescribed solely for the treatment of acute attacks.

How to Take Naratriptan

Take one naratriptan 2.5 mg tablet with water as soon as possible after the start of the migraine headache. It can be taken with or without food. If the migraine returns after initial relief, a second dose may be taken, provided at least four hours have elapsed since the first tablet. Do not take more than two tablets in 24 hours.

Naratriptan is particularly suited to patients whose migraines develop gradually and last a long time, and to women with menstrual migraine. Its lower rate of side effects compared to more potent triptans makes it a good option for those who have experienced significant discomfort (chest tightness, dizziness, flushing) with other triptans.

The recommended dose of naratriptan is 2.5 mg (one tablet) taken orally at the onset of migraine headache. If the headache resolves and then recurs, a second 2.5 mg tablet may be taken, but only after an interval of at least four hours from the first dose. The maximum total dose in any 24-hour period is 5 mg (two tablets).

If the first dose does not relieve the migraine, a second tablet should not be taken for that same attack. Naratriptan is not recommended for patients with mild to moderate hepatic or renal impairment beyond a maximum single dose of 2.5 mg in 24 hours, and is contraindicated in severe impairment. It is not recommended for patients under 18 or over 65 years. Tablets should be swallowed whole with a glass of water. Naratriptan can be taken with or without food, though nausea associated with migraine may make this a practical consideration.

Common Side Effects

Naratriptan is considered among the better-tolerated triptans, but the following effects are still reported:

• Sensations of tingling, warmth, or numbness affecting the face, neck, or extremities
• Fatigue and drowsiness
• Nausea, with or without vomiting
• Dizziness
• Feelings of heaviness, pressure, or tightness in the chest, throat, or neck (usually transient and not cardiac in origin)
• Headache or migraine recurrence within 24 hours of initial response
• Palpitations or awareness of heartbeat
• Blurred vision (uncommon)

Serious Side Effects

Seek immediate medical help if any of the following occur:

• Chest pain or pressure with breathlessness or sweating may indicate myocardial ischaemia or coronary artery spasm
• Sudden onset of severe headache, visual loss, weakness or speech disturbance may indicate stroke or transient ischaemic attack
• Severe allergic reaction - anaphylaxis with rash, throat swelling, difficulty breathing
• Serotonin syndrome - agitation, confusion, muscle rigidity, tremor, rapid heart rate, fever: particularly if naratriptan is combined with SSRIs, SNRIs, or MAOIs
• Hypertensive crisis, particularly in patients with undiagnosed hypertension

Cardiovascular Safety

Naratriptan must not be used in patients with any form of cardiovascular disease, including known or suspected coronary artery disease, prior myocardial infarction, stroke, or peripheral arterial disease. Like all triptans, it causes vasoconstriction and can precipitate coronary vasospasm. In patients with cardiovascular risk factors (smoking, diabetes, hypertension, hyperlipidaemia, strong family history), naratriptan should only be used after a cardiovascular assessment and under medical supervision. The chest tightness and pressure sensations commonly reported with triptans are usually benign in nature, but if associated with other cardiac symptoms (sweating, jaw pain, arm pain, shortness of breath), emergency evaluation is needed.

Medication Overuse and Drug Interactions

Frequent use of naratriptan - taking it on 10 or more days per month - can lead to medication overuse headache (MOH), a condition in which headaches become more frequent and more difficult to treat. Patients should track how often they use naratriptan and discuss any increase in frequency with their doctor. Naratriptan should not be used within 24 hours of ergotamine or ergotamine derivatives, or concurrently with other triptans. The combination with SSRIs or SNRIs requires clinical vigilance for serotonin syndrome. Naratriptan is not recommended during pregnancy or breastfeeding. Alcohol may worsen migraine and increase the likelihood of side effects from naratriptan.

Naratriptan must not be used in patients with:

• Known ischaemic heart disease, documented coronary artery disease, or Prinzmetal's angina
• History of stroke or transient ischaemic attack
• Peripheral vascular disease
• Uncontrolled hypertension or severe hypertension
• Severe hepatic impairment (Child-Pugh Grade C)
• Severe renal impairment (creatinine clearance below 15 mL/min)
• Haemiplegic migraine, basilar migraine, or ophthalmoplegic migraine
• Current or recent use (within 24 hours) of ergotamine, dihydroergotamine, methysergide, or any other triptan
• Known hypersensitivity to naratriptan hydrochloride or any excipient
• Patients under 18 or over 65 years of age