Common use
Imitrex is the brand name for sumatriptan, a triptan-class medicine used for the acute treatment of migraine attacks, with or without aura, and for certain patients with cluster headaches. It is not a preventive (prophylactic) therapy; instead, it is intended to be taken at the first sign of an attack to shorten duration and reduce intensity of symptoms like throbbing pain, nausea, photophobia, and phonophobia. Sumatriptan selectively stimulates 5‑HT1B/1D receptors, which constrict dilated cranial blood vessels and inhibit release of pro-inflammatory neuropeptides in the trigeminovascular system.
Imitrex comes in multiple formulations to match symptom onset and patient preference: oral tablets (commonly 25 mg, 50 mg, 100 mg), a nasal spray (5 mg, 10 mg, 20 mg), and a subcutaneous injection (typically 4 mg or 6 mg) including autoinjector options. In general, injections provide the fastest relief for rapidly escalating attacks or cluster headaches; nasal spray offers an alternative when nausea limits oral dosing; tablets are convenient for many migraineurs whose symptoms build more gradually.
Dosage and direction
Use Imitrex only as prescribed for you, and follow the product-specific instructions. Typical adult oral dosing for migraine is 25–100 mg taken at onset; if the headache improves but returns, a second dose may be taken at least 2 hours after the first, not to exceed 200 mg in 24 hours. For the nasal spray, a single 5–20 mg dose at onset may be repeated after a minimum of 2 hours if needed, up to 40 mg in 24 hours. For subcutaneous injection, 4–6 mg at onset may be repeated after at least 1 hour, up to 12 mg in 24 hours.
For cluster headaches, subcutaneous injection is often preferred due to rapid onset. Pediatric use varies by formulation and indication; consult a clinician experienced in pediatric headache management. Do not split or crush tablets unless directed. If nausea or vomiting is prominent, a non-oral route may be more effective. Medication-overuse headache can occur if acute therapies are used too frequently; many clinicians advise limiting triptan use to fewer than 10 days per month. Always ask your prescriber about a personalized plan, including non-drug strategies and preventive options if your attack frequency is high.
Precautions
A cardiovascular evaluation is prudent before starting Imitrex in patients with risk factors for coronary artery disease (for example, hypertension, hyperlipidemia, diabetes, smoking, obesity, or a strong family history) and in men over 40 or postmenopausal women. Because sumatriptan can constrict blood vessels, people with known vascular disease need careful assessment. Seek immediate care for chest pain, shortness of breath, severe abdominal pain, or neurologic symptoms such as one-sided weakness or difficulty speaking.
Use caution if you have hepatic impairment; severe liver disease is a contraindication. Triptans may rarely precipitate seizures in predisposed individuals. Serotonin syndrome is a potential risk when combined with other serotonergic drugs; know the warning signs (agitation, confusion, fever, tremor, muscle rigidity, rapid heart rate). Triptans can cause transient sensations of pressure or tightness in the chest, neck, jaw, or throat; while often benign, evaluate new or unusual symptoms. Avoid using Imitrex within 24 hours of other triptans or ergot-type medications. If attacks are frequent, discuss preventive therapies such as CGRP antagonists, beta-blockers, or topiramate.
Contraindications
Do not use Imitrex if you have any of the following unless a clinician explicitly determines otherwise: coronary artery disease, coronary vasospasm (Prinzmetal’s angina), history of myocardial infarction, uncontrolled hypertension, peripheral vascular disease, cerebrovascular disease (including stroke or transient ischemic attack), hemiplegic migraine, basilar/brainstem migraine, Wolff–Parkinson–White or other significant cardiac conduction disorders, or severe hepatic impairment. It is contraindicated within 24 hours of ergotamine-containing drugs or other triptans due to additive vasoconstriction.
Use is also contraindicated with monoamine oxidase inhibitors (MAOIs) or within 2 weeks of stopping an MAOI, because sumatriptan is metabolized by MAO-A and exposure can rise dangerously. Hypersensitivity to sumatriptan or formulation excipients precludes use. For pregnancy and lactation, risk–benefit discussions are individualized; while some data are reassuring, decisions should be made with your obstetric and neurology teams.
Possible side effects
Common, typically transient effects include paresthesia (tingling), flushing, warmth, pressure or tightness sensations (chest, throat, neck, jaw), dizziness, drowsiness, fatigue, and mild nausea. With injections, localized pain, redness, or swelling can occur; with nasal spray, taste disturbance or nasal discomfort is possible. These symptoms often resolve as the attack improves. Staying hydrated, resting in a dark quiet room, and using adjunctive antiemetics for nausea may improve tolerability during attacks.
Serious adverse events are uncommon but require urgent attention: chest pain suggestive of ischemia, rapid or irregular heartbeat, shortness of breath, signs of stroke (sudden weakness, facial droop, speech difficulties), severe abdominal pain (possible mesenteric ischemia), visual changes, seizures, or severe allergic reactions (hives, swelling, breathing difficulty). Serotonin syndrome presents with agitation, confusion, sweating, fever, muscle twitching, tremor, and diarrhea—especially when combined with SSRIs, SNRIs, MAOIs, linezolid, methylene blue, or other serotonergic agents. Report new or worsening headaches, as well as headaches occurring more than 15 days per month, which may suggest medication overuse and require a preventive strategy.
Drug interactions
Avoid combining Imitrex with other triptans or ergot derivatives (ergotamine, dihydroergotamine) within 24 hours due to additive vasoconstriction. Do not use with MAOIs or within 2 weeks after discontinuation. Caution is advised with SSRIs, SNRIs, tricyclic antidepressants, mirtazapine, trazodone, buspirone, lithium, tramadol, linezolid, methylene blue, and St. John’s wort; the combined serotonergic load can raise the risk of serotonin syndrome. While occasional alcohol does not directly interact, it may worsen migraine susceptibility and can confound evaluation of side effects.
Sumatriptan’s metabolism and pharmacodynamics can be affected by hepatic function; severe impairment is a contraindication. Although pharmacokinetic interactions via CYP enzymes are limited for sumatriptan, always provide a complete medication and supplement list to your clinician, including decongestants (which may elevate blood pressure), nicotine replacement, and caffeine products. If you use preventive migraine medications (CGRP monoclonal antibodies, gepants, beta-blockers, topiramate, valproate), your clinician will coordinate timing to minimize overlap and avoid medication-overuse patterns. Consider an updated ECG and blood pressure assessment if you start or change any drug with cardiovascular effects.
Missed dose
Because Imitrex is taken as needed at the onset of an attack, there is no routine “missed dose.” If you did not take it when symptoms started and the migraine is ongoing, you may take it according to your prescriber’s instructions. Do not use Imitrex prophylactically to prevent attacks, and do not exceed the maximum daily dose for your formulation. If a dose was vomited shortly after taking an oral tablet, ask your clinician whether and when a repeat dose is appropriate.
Overdose
Signs of overdose can include marked elevation in blood pressure, fainting, severe dizziness, agitation, tremor, drowsiness, loss of coordination, rapid or irregular heartbeat, chest pain, bluish fingers/toes, seizures, or symptoms of serotonin syndrome. Overdose risk rises when multiple serotonergic agents or vasoconstrictors are combined, or when maximum daily limits are exceeded.
If you suspect an overdose or severe reaction, call emergency services immediately. In the U.S., you can also contact Poison Control at 1‑800‑222‑1222 or use poisonhelp.org for guidance while awaiting care. Bring medication packaging to the emergency department to assist clinicians. Do not attempt to self-treat serious symptoms at home. After stabilization, your care team can reassess your treatment plan to prevent recurrence, which may include dose adjustments, switching formulations, or adding a preventive regimen.
Storage
Store Imitrex at controlled room temperature (generally 68–77°F or 20–25°C), away from excessive heat, moisture, and light. Keep tablets in their original blister packs until use. Do not freeze the nasal spray or injection. For autoinjectors and prefilled syringes, follow the device-specific storage instructions and check expiration dates regularly. Keep all medications out of reach of children and pets. Do not use if packaging is damaged or shows evidence of tampering.
U.S. Sale and Prescription Policy
In the United States, Imitrex (sumatriptan) is an FDA-approved prescription medication. It is not available over the counter, and it is unsafe and unlawful to purchase prescription triptans from sources that do not require a valid prescription. To access Imitrex legally and safely, you must be evaluated by a licensed clinician who can confirm the diagnosis, screen for cardiovascular risks and drug interactions, and send an electronic prescription to a U.S.-licensed pharmacy if appropriate.
Geisinger HealthSouth supports streamlined, compliant access by coordinating medical evaluation—often via telehealth—followed by pharmacy dispensing when clinically indicated. This approach preserves patient safety, ensures proper dosing and education, and meets regulatory requirements. If you are seeking treatment, schedule a visit (in person or virtual) with a qualified provider to discuss your migraine history, triggers, and prior responses to therapy. Beware of websites promising to “buy Imitrex without prescription”; such offers can involve counterfeit or substandard products and bypass critical safety checks. The safest path is clinician-guided care with legitimate pharmacy fulfillment.
