Naratriptan is a selective serotonin (5-HT1B/1D) receptor agonist belonging to the class of medications known as triptans, primarily used for the acute treatment of migraine headaches with or without aura in adults.[1][2] It works by binding to 5-HT1B and 5-HT1D receptors in the brain, leading to vasoconstriction of dilated cranial blood vessels and inhibition of the release of pro-inflammatory neuropeptides from trigeminal nerve endings, thereby relieving migraine pain, nausea, and sensitivity to light and sound.[2][3][4]Approved by the U.S. Food and Drug Administration (FDA) in 1998 under the brand name Amerge, naratriptan is available in oral tablet form, typically in 1 mg and 2.5 mg doses, with a recommended starting dose of 1 mg or 2.5 mg taken as soon as possible after the onset of a migraine attack; a second dose may be taken after at least 4 hours if needed, but not exceeding 5 mg in 24 hours.[5][2] It is distinguished among triptans by its longer half-life (approximately 6 hours), which provides prolonged relief lasting up to 24 hours or more, and a slower onset of action compared to some counterparts like sumatriptan.[6][7]Common side effects include paresthesia, dizziness, drowsiness, fatigue, and sensations of tightness or pressure in the throat or neck, which are generally mild and similar in frequency to placebo.[8][9] More serious risks, though rare, involve cardiovascular events such as myocardial infarction or stroke due to vasoconstrictive effects, necessitating contraindications in patients with ischemic heart disease, uncontrolled hypertension, or use of ergotamine-containing drugs within 24 hours.[2][3] Naratriptan is primarily excreted by the kidneys, requiring dose adjustments in patients with renal impairment (creatinine clearance <30 mL/min) and caution in the elderly due to increased risk of adverse reactions.[2] As a first-line therapy for acute migraines, it offers effective pain relief in about 40-50% of patients at 2 hours post-dose, with low recurrence rates due to its extended duration of action.[3][9]
Medical uses
Indications
Naratriptan is indicated for the acute treatment of migraine headaches with or without aura in adults.[10] It is specifically approved for relieving the pain of migraine attacks and associated symptoms, such as nausea, vomiting, photophobia, and phonophobia.[11][10]Naratriptan is not indicated for migraine prophylaxis, the treatment of hemiplegic or basilar migraine, cluster headaches, or other non-migraine headaches.[2][10] Its use is restricted to patients with a confirmed diagnosis of migraine, and it is approved only for adults aged 18 years and older, with limited data available on safety and efficacy in pediatric populations.[10]
Dosage and administration
Naratriptan is available as oral tablets in strengths of 1 mg and 2.5 mg. The recommended initial dose for the acute treatment of migraine is 1 mg or 2.5 mg taken orally as a single dose at the onset of the attack, with or without food.[2] The choice of starting dose should be individualized based on the patient's response to the initial dose; a lower starting dose of 1 mg may be considered for patients who experience side effects with the 2.5 mg dose.[12] Tablets should be swallowed whole with fluids.[2]If the migraine headache returns after initial relief, a second dose of 1 mg or 2.5 mg may be taken at least 4 hours after the first dose.[2] The maximum recommended dose in any 24-hour period is 5 mg.[12] Although food does not affect the overall bioavailability of naratriptan, administration with food may delay the time to peak plasma concentrations by 2 to 3 hours.[2]In patients with mild or moderate renal impairment (creatinine clearance of 15 to 59 mL/min), the recommended starting dose is 1 mg, with a maximum daily dose of 2.5 mg in any 24-hour period.[2] Naratriptan is contraindicated in patients with severe renal impairment (creatinine clearance less than 15 mL/min).[2] Similarly, for mild or moderate hepatic impairment (Child-Pugh class A or B), the starting dose should be reduced to 1 mg, not exceeding 2.5 mg per 24 hours; naratriptan is contraindicated in severe hepatic impairment (Child-Pugh class C).[2]To minimize the risk of medication-overuse headache, patients should limit naratriptan use to treating no more than four headaches on average in a 30-day period, and the safety of more frequent use has not been established.[2] Patients should be advised to consult their healthcare provider if headaches occur more frequently than this threshold.[13]
Efficacy
Naratriptan 2.5 mg has demonstrated efficacy in phase III clinical trials for the acute treatment of moderate to severe migraine attacks. In pooled analyses of randomized, double-blind, placebo-controlled studies involving over 1,000 patients, headache relief (defined as reduction from moderate or severe pain to mild or none) was achieved in 62-68% of patients within 4 hours post-dose, compared to 35-40% with placebo. Pain-free rates at 2 hours ranged from 21-28%, rising to 36-41% at 4 hours, significantly outperforming placebo rates of 10-17% at both time points. These results were consistent across multiple trials, establishing naratriptan as an effective option for migraine relief, though with a somewhat slower onset than some alternatives.[14][2][9]The drug also effectively alleviates associated migraine symptoms. In the same phase III trials, nausea was resolved in 60-70% of affected patients at 4 hours, versus 30-40% with placebo. Similarly, relief from photophobia and phonophobia occurred in 50-65% of cases, exceeding placebo responses by approximately 20-30 percentage points. These symptom improvements contribute to overall functional recovery, with reduced clinical disability reported in 55-60% of naratriptan-treated patients compared to 25-30% on placebo.[9][2]Naratriptan's longer elimination half-life of about 6 hours enables sustained relief extending up to 24 hours, offering an advantage over shorter-acting triptans like sumatriptan (half-life 2-3 hours). Head-to-head comparisons in randomized trials showed naratriptan with a less rapid onset—pain-free rates of 25% at 2 hours versus 29-32% for sumatriptan 100 mg—but comparable or superior 24-hour sustained response rates. Recurrence of headache within 24 hours after initial relief was lower with naratriptan (17-25%) than with sumatriptan (25-35%), attributed to its pharmacokinetic profile. Overall, naratriptan balances moderate speed with enhanced tolerability and durability of effect.[15][16][2]While effective for typical migraine attacks, naratriptan shows reduced efficacy in cases dominated by severe nausea or vomiting, where gastrointestinal absorption may be compromised, potentially necessitating non-oral formulations of other triptans. It provides no benefit for migraine prevention, as it is indicated solely for acute treatment.[17][2]
Adverse effects
Common side effects
Common side effects of naratriptan are generally mild and transient, with an overall incidence of drug-related adverse reactions similar to placebo in controlled clinical trials, though specific effects occur more frequently with the drug.[2] These effects typically begin within 2-4 hours of dosing, coinciding with the drug's peak plasma concentrations, and resolve spontaneously within 24 hours in most cases.[2]The most common adverse reactions, reported in at least 2% of patients and more frequently than with placebo, are summarized in the following table based on five placebo-controlled trials involving approximately 1,752 exposures to naratriptan or placebo in adult patients:
Adverse Reaction
Naratriptan 1 mg (%)
Naratriptan 2.5 mg (%)
Placebo (%)
Paresthesias (all types)
2
4
<1
Nausea
6
7
5
Dizziness
4
7
3
Drowsiness
1
2
<1
Malaise/Fatigue
1
2
1
Throat/Neck Symptoms
2
4
2
Paresthesias, often described as tingling or numbness in the extremities, affect up to 4% of users.[2] Dizziness occurs in 4-7% of patients, while drowsiness and malaise or fatigue are reported in 1-2%, contributing to a sense of tiredness shortly after administration.[2] Nausea, experienced by 6-7%, is also a frequent gastrointestinal complaint, though less severe than those associated with acute migraine itself.[2]The incidence of these side effects is dose-dependent, with slightly higher rates observed at 2.5 mg compared to 1 mg, but the overall profile remains favorable due to their mild nature.[2] No significant differences were noted based on gender, age, weight, or migraine duration prior to treatment.[2]
Serious adverse effects
Naratriptan, a selective serotonin (5-HT1B/1D) receptor agonist, carries risks of serious cardiovascular adverse effects, primarily due to its vasoconstrictive properties, which can lead to coronary artery vasospasm, myocardial ischemia, or infarction. These events are rare, with no reports in clinical trials but occurrences noted in post-marketing surveillance, including acute myocardial infarction within hours of administration. Exacerbation of hypertension has also been observed, particularly in patients with preexisting cardiovascular conditions.[2][2]Neurological risks include serotonin syndrome, a potentially life-threatening condition characterized by autonomic instability, neuromuscular abnormalities, and altered mental status, which may occur when naratriptan is used concomitantly with selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs). The risk of serotonin syndrome is very rare, with one population-based study reporting rates of 0.6 definite cases to 2.3 including possible cases per 10,000 person-years (0.006-0.023%) in patients coprescribed triptans and these antidepressants.[18] Cerebrovascular events, such as ischemic stroke, are also rare, occurring at rates below 0.1% in clinical use, potentially linked to cerebral vasoconstriction.[18]Other serious effects encompass medication-overuse headache, which can develop with chronic or excessive use (more than 10 days per month), leading to a paradoxical increase in headache frequency and severity. Hypersensitivity reactions, including rash, angioedema, and anaphylaxis, have been reported post-marketing, though their incidence is not well-quantified in trials.[2][19]For patients with cardiac risk factors, such as coronary artery disease or uncontrolled hypertension, electrocardiogram (ECG) monitoring is recommended following the initial dose to detect ischemic changes, given the potential for subclinical vasospasm. This precaution helps mitigate undetected cardiovascular events in at-risk individuals.[12][20]
Contraindications
Naratriptan is contraindicated in patients with ischemic coronary artery disease, including angina pectoris, history of myocardial infarction, or documented silent ischemia, due to the risk of coronary vasospasm and serious cardiovascular events.[2] It is also contraindicated in individuals with coronary artery vasospasm, such as Prinzmetal's angina, Wolff-Parkinson-White syndrome, or other cardiac accessory conduction pathway disorders, as these conditions increase the potential for life-threatening arrhythmias.[2] Cerebrovascular syndromes, including stroke, transient ischemic attack, or a history thereof, represent absolute contraindications because naratriptan may exacerbate ischemic events. Hemiplegic or basilar migraine is also contraindicated.[2] Additionally, peripheral vascular disease and uncontrolled hypertension preclude its use, as the drug's vasoconstrictive effects could precipitate ischemia or hypertensive crisis.[2]The medication is contraindicated in cases of hypersensitivity to naratriptan or any of its components, which may lead to anaphylaxis or angioedema.[2] Naratriptan should not be administered within 24 hours of another 5-HT1 agonist (triptan) or an ergotamine-containing or ergot-type medication, such as dihydroergotamine or ergotamine, to avoid additive vasospastic reactions.[2] Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 2 weeks of their discontinuation is prohibited due to increased exposure to naratriptan and risk of serotonin syndrome.[2] Caution is advised with selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs), as their combination with naratriptan may heighten the risk of serotonin syndrome, though not an absolute contraindication.[2]Severe renal impairment (creatinine clearance less than 15 mL/min) and severe hepatic impairment (Child-Pugh grade C) are contraindications, stemming from significantly reduced drug clearance and potential for accumulation.[2] In pregnancy, naratriptan is classified as category C, with limited human data indicating potential fetal risk, and its use is recommended only if the benefit justifies the potential harm.[2] During lactation, naratriptan is excreted in human milk, and administration is generally avoided to prevent exposure in nursing infants.[2]
Pharmacology
Mechanism of action
Naratriptan acts as a selective agonist at serotonin 5-HT<sub>1B</sub> and 5-HT<sub>1D</sub> receptors, exhibiting high binding affinity with Ki values of approximately 2.2 nM for 5-HT<sub>1B</sub> and 2.3 nM for 5-HT<sub>1D</sub>. Naratriptan also exhibits high affinity for 5-HT<sub>1F</sub> receptors (Ki ≈ 4 nM), which may play a role in inhibiting trigeminal nociception.[21] This affinity profile contributes to its specificity in targeting migraine-related pathways, while it demonstrates low affinity for other serotonin receptor subtypes, such as 5-HT<sub>1A</sub>, 5-HT<sub>2</sub>, 5-HT<sub>3</sub>, 5-HT<sub>4</sub>, 5-HT<sub>5A</sub>, and 5-HT<sub>7</sub>.[21]The vascular effects of naratriptan primarily involve activation of 5-HT<sub>1B</sub> receptors located on the smooth muscle cells of cranial blood vessels, leading to vasoconstriction of abnormally dilated extracerebral and intracranial arteries associated with migraine attacks.[2] This contraction helps normalize vessel diameter and alleviate the throbbing pain characteristic of migraines. Complementing this, naratriptan's interaction with 5-HT<sub>1D</sub> receptors on peripheral trigeminal nerve terminals inhibits the release of pro-inflammatory neuropeptides, including calcitonin gene-related peptide (CGRP) and substance P, thereby reducing neurogenic inflammation and nociceptive signaling to the central nervous system.[22][23]Naratriptan's pharmacological selectivity extends to minimal interaction with non-serotonergic systems, showing no significant affinity or activity at dopamine or norepinephrine transporters, which helps limit off-target cardiovascular or central nervous system effects beyond its intended antimigraine actions.[21] This profile underscores its design as a targeted therapy for migraine relief through precise modulation of serotonergic mechanisms in the trigeminovascular system.
Pharmacokinetics
Naratriptan is well absorbed following oral administration, with an absolute bioavailability of approximately 74% in females and 63% in males.[24] The time to reach maximum plasma concentration (T<sub>max</sub>) is typically 2 to 3 hours under normal conditions, though it may extend to 3 to 4 hours during a migraine attack due to delayed gastric emptying.[8] Food has minimal impact on overall exposure, as it does not alter the area under the curve (AUC), but it can delay T<sub>max</sub> by about 0.5 to 1 hour.[25]The volume of distribution of naratriptan is approximately 170 L, indicating moderate distribution into body tissues.[21]Plasma protein binding is low, ranging from 28% to 31% across therapeutic concentrations, which contributes to its availability for tissue distribution.[21] Naratriptan, due to its greater lipophilicity compared to sumatriptan, crosses the blood-brain barrier more readily than some other triptans, potentially allowing for both peripheral and central mechanisms in migraine treatment.[26]Naratriptan undergoes hepatic metabolism primarily through cytochrome P450 enzymes, including CYP1A2, and is also partially metabolized by monoamine oxidase-A (MAO-A).[3] The primary metabolites are inactive and do not contribute to pharmacological effects.[24]Elimination of naratriptan occurs mainly via the kidneys, with approximately 60% to 70% of the dose excreted unchanged in urine.[25] The elimination half-life ranges from 5 to 6 hours, supporting once-daily dosing for many patients.[21] Renal clearance is estimated at 220 mL/min, while systemic clearance is about 6.6 mL/min/kg, and fecal excretion accounts for less than 10% of the dose.[27]In special populations, pharmacokinetics are altered in those with renal or hepatic impairment. In patients with moderate renal impairment (creatinine clearance 18 to 39 mL/min), clearance is reduced by approximately 50%, leading to about 100% higher AUC compared to healthy individuals, necessitating dose adjustments.[28] Severe renal impairment (creatinine clearance <15 mL/min) is contraindicated due to markedly decreased clearance and prolonged exposure.[29] In moderate hepatic impairment (Child-Pugh class A or B), clearance decreases by about 30%, resulting in 40% to 50% higher exposure; severe hepatic impairment has not been fully evaluated but warrants caution.[28]
Chemistry
Chemical structure
Naratriptan has the molecular formula C_{17}H_{25}N_{3}O_{2}S and a molecular weight of 335.47 g/mol.[21]Its IUPAC name is N-methyl-2-[3-(1-methylpiperidin-4-yl)-$1H$-indol-5-yl]ethanesulfonamide.[21]The core structure consists of an indole ring substituted at the 3-position with a (1-methylpiperidin-4-yl) group and at the 5-position with a 2-(methylsulfamoyl)ethyl chain (-CH_2CH_2SO_2NHCH_3).[21]This configuration positions naratriptan within the class of tryptamine derivatives, though it diverges from classical tryptamines by incorporating a piperidine ring at the 3-position in place of the typical ethylamine side chain.As a second-generation triptan, naratriptan shares structural similarities with sumatriptan—particularly the indole core and sulfonamide functionality—but features the piperidine substitution at position 3, which enhances its pharmacokinetic profile, including greater oral bioavailability and a longer half-life.[21][30]The compound is formulated for clinical use as the hydrochloride salt, with the molecular formula C_{17}H_{26}ClN_{3}O_{2}S and a molecular weight of 371.93 g/mol, suitable for oral tablet administration.[31]
Physical and chemical properties
Naratriptan hydrochloride appears as a white to pale yellow crystalline powder. This form facilitates its handling and incorporation into pharmaceutical formulations.[25]The hydrochloride salt is readily soluble in water, with a solubility of 35 mg/mL at 25°C, while the free base exhibits lower aqueous solubility of approximately 0.114 mg/mL. It is slightly soluble in methanol and ethanol. Naratriptan has a pKa of 9.7, indicating basic character, and a logP of 1.6, reflecting moderate lipophilicity that supports its absorption profile.[1][21][24][32]Naratriptan is chemically stable under standard storage conditions at controlled room temperature (15–30°C) and protected from light. The hydrochloride salt has a melting point of 234–236°C. As an achiral molecule with no stereocenters, it lacks optical isomers, simplifying its synthesis and formulation. These properties make naratriptan suitable for oral tablet formulations in 1 mg and 2.5 mg strengths.[33][34][1][2]In toxicity studies, the oral LD50 of naratriptan hydrochloride exceeds 750 mg/kg in rats. Naratriptan shows low potential for environmental bioaccumulation due to its metabolic degradation pathways.[35][36]
History
Development
Naratriptan was developed by Glaxo Wellcome in the 1990s as a second-generation triptan, building on the success of sumatriptan—the first triptan, approved in 1992—to enhance tolerability, metabolic stability, oral bioavailability, and duration of action while reducing side effects like chest tightness.[37][26] The compound, chemically an indole derivative, was designed to more selectively target serotonin 5-HT1B/1D receptors implicated in migrainepathophysiology.[38]Preclinical research focused on synthesizing naratriptan with high affinity for 5-HT1B/1D receptors, achieving greater selectivity than sumatriptan to minimize off-target effects. In animal models, such as cats and rodents, naratriptan demonstrated cranial vasoconstriction through 5-HT1B receptor activation on vascular smooth muscle and inhibition of trigeminovascular neurotransmission via 5-HT1D receptors on sensory nerves, effectively reducing neurogenic inflammation without significant systemic vasoconstriction or cardiovascular risks.[39] These studies confirmed its potential for migraine-specific efficacy with an improved safety margin.[40]Phase I trials in the mid-1990s evaluated single oral doses in healthy volunteers, establishing pharmacokinetics and tolerability with no serious adverse events.[24] Phase II and early phase III trials, conducted between 1996 and 1997, confirmed safety and efficacy in migraine patients; a double-blind, placebo-controlled crossover study showed 2.5 mg naratriptan achieved headache relief in 68% of patients at 4 hours (versus 33% for placebo), with sustained relief at 24 hours and reduced recurrence.[9] A dose-ranging trial further demonstrated 2.5 mg naratriptan provided relief comparable to 100 mg sumatriptan but with lower 24-hour recurrence rates (around 20% versus 30-40% for sumatriptan) and better tolerability.[41]The core compound was covered by US Patent 4,997,841, filed in 1988 and issued on March 5, 1991, to Glaxo Group Limited, protecting its use for migraine and related headaches.[38] This milestone facilitated progression to clinical development, evolving from sumatriptan's limitations in offset speed and side effects to naratriptan's profile of prolonged action and fewer adverse events.[37]
Regulatory approvals
Naratriptan received initial approval from the U.S. Food and Drug Administration (FDA) on February 10, 1998, for the acute treatment of migraine headaches with or without aura in adults.[5] It was marketed under the brand name Amerge by GlaxoSmithKline.[42]In Europe, naratriptan was first approved in 1997 by national regulatory authorities, and marketed as Naramig for the acute treatment of migraines.[43]The first generic versions of naratriptan were approved by the FDA in the United States in 2010, following the expiration of key patents, allowing for broader market entry and increased accessibility.[44] The brand name Amerge was discontinued in the United States in 2022, with generic versions continuing to be available.[45] By 2025, naratriptan has been approved and is available in over 50 countries worldwide, including major markets in North America, Europe, Asia, and Latin America, reflecting its established role in migraine management.[46][47]Post-marketing surveillance has included updates to labeling for potential risks. In July 2006, the FDA issued an alert for all triptans, including naratriptan, warning of the rare but serious risk of serotonin syndrome when used concomitantly with selective serotonin reuptake inhibitors (SSRIs) or serotonin-norepinephrine reuptake inhibitors (SNRIs), leading to revised warnings in product labels.[48] No major withdrawals or revocations of approval have occurred for naratriptan since its initial authorization.[2]As of 2025, naratriptan retains its original indication for acute migraine treatment with no new approvals for additional uses. Regulatory labels continue to emphasize ongoing monitoring for cardiovascular risks, such as myocardial ischemia or infarction, particularly in patients with underlying risk factors, based on pharmacovigilance data and clinical studies showing no significant increase in events with appropriate use.[49][2][50]
Society and culture
Brand names and formulations
Naratriptan is marketed under the brand name Amerge in the United States by GlaxoSmithKline.[2] Internationally, it is sold as Naramig, also by GlaxoSmithKline in many regions including the United Kingdom and Europe.[51] Note that the Amerge brand has been discontinued in the US market, though it was not withdrawn for safety or efficacy reasons.[45]Generic versions of naratriptan hydrochloride are widely available, primarily as oral tablets in 1 mg and 2.5 mg strengths.[52] Approved manufacturers include Mylan Pharmaceuticals (ANDA approved in 2010 for 1 mg and 2.5 mg tablets), Teva Pharmaceuticals, Aurobindo Pharma USA, and Ani Pharmaceuticals, among others.[53][54]Naratriptan is formulated exclusively as immediate-release oral tablets, with no approved nasal spray, injectable, or extended-release preparations.[2] Common inactive ingredients in both brand and generic formulations include croscarmellose sodium, hypromellose, lactose monohydrate, magnesium stearate, microcrystalline cellulose, titanium dioxide, and triacetin, though some generic versions offer lactose-free options for patients with lactose intolerance.[27] As of 2025, no major brands or formulations of naratriptan have been discontinued or withdrawn globally for safety concerns.[54]
Availability and legal status
Naratriptan is classified as a prescription-only medication in the United States, where it requires a valid prescription from a healthcare provider and is not a controlled substance under the DEA scheduling system.[2] In the European Union, it similarly holds prescription status across member states, though specific implementations may vary by country; for instance, it is available over-the-counter in Germany since 2006 for certain low-dose formulations.[55] Globally, naratriptan mandates a prescription in most jurisdictions, including Canada and Australia, to ensure appropriate use for acute migraine treatment under medical supervision.[19][56]Naratriptan is widely accessible in North America, Europe, and parts of Asia through pharmacies and healthcare providers, with generic versions approved and distributed in these regions following the expiration of key patents. The original U.S. patent for naratriptan expired on August 12, 2008, enabling generic entry, while in Canada, generics became available after December 1, 2009.[57][58] In Asia, availability is robust in countries like Japan and India, supported by local manufacturing and imports, though distribution may be limited in rural areas.[59] The introduction of generics has significantly expanded access, particularly in mature markets where brand-name Amerge was discontinued by 2025.[45]In the United States, the cost of generic naratriptan has decreased due to genericcompetition, with prices averaging around $14 to $22 for a 9-tablet pack (2.5 mg each) as of 2025, equating to approximately $1.50 to $2.50 per dose without insurance.[60][61] Most U.S. insurance plans, including Medicare Part D, cover naratriptan for migraine treatment, with 93% of plans providing reimbursement and typical copays ranging from $3 to $7 per prescription.[62] Access remains prescription-based worldwide, with no over-the-counter availability in the U.S., Canada, or most EU countries outside specific exceptions like Germany.[19][55]Legally, naratriptan faces no outright bans globally, but its use is restricted in patients with certain cardiovascular conditions due to potential vasoconstrictive effects. It is contraindicated in individuals with ischemic heart disease, coronary artery vasospasm, uncontrolled hypertension, or a history of stroke, as per FDA and EMA guidelines, requiring cardiovascular screening before initiation.[2][63] Patent expirations between 2008 and 2011 across regions have facilitated generic production without ongoing exclusivity issues.[64]Post-2020, generic penetration for naratriptan has increased, particularly in low- and middle-income countries, driven by expanded manufacturing in India and China, which has improved affordability and supply chain stability. This shift has reduced prices by up to 50% in emerging markets compared to branded versions, enhancing access for migraine patients in resource-limited settings.[65][66]