Usage
Sumatriptan is prescribed for the acute treatment of migraine attacks, with or without aura, and cluster headaches. It is not intended for preventative use. It is classified as a selective serotonin receptor agonist, specifically a 5-HT1B/1D agonist, and belongs to the triptan class of antimigraine drugs. Sumatriptan works by constricting cranial blood vessels, inhibiting the release of neuropeptides involved in pain transmission, and reducing inflammation associated with migraine and cluster headaches.
Alternate Names
Sumatriptan is also known internationally by its generic name. Brand names include Imitrex, Imitrex StatDose, Sumavel DosePro, Alsuma, and Zembrace SymTouch.
How It Works
Pharmacodynamics: Sumatriptan primarily acts as a selective agonist at 5-HT1B and 5-HT1D receptors. Stimulation of 5-HT1B receptors on intracranial blood vessels leads to vasoconstriction, which is thought to be the primary mechanism of action in migraine. Activation of 5-HT1D receptors inhibits the release of pro-inflammatory neuropeptides, such as calcitonin gene-related peptide (CGRP), from trigeminal nerve endings, further contributing to pain relief. Sumatriptan has minimal effects on other serotonin receptor subtypes (5-HT2, 5-HT3, 5-HT4, 5-HT7).
Pharmacokinetics: Sumatriptan, when administered orally, is well absorbed, reaching peak plasma concentrations in approximately 1-2 hours. It undergoes extensive hepatic metabolism primarily by monoamine oxidase A (MAO-A), resulting in inactive metabolites. The elimination half-life is around 2 hours, and excretion is mainly through the kidneys. Subcutaneous administration results in a faster onset of action (peak plasma levels in about 10-15 minutes). Nasal administration produces effects within approximately 15 minutes.
Dosage
Standard Dosage
Adults:
Oral: Initial dose: 25 mg to 100 mg. A second dose may be taken if the migraine returns, but not earlier than 2 hours after the first dose. Maximum daily dose: 200 mg (some sources state 300 mg) within a 24-hour period.
Subcutaneous injection: 1 mg to 6 mg. A second injection may be given after at least 1 hour if symptoms persist or return. Maximum daily dose: 12 mg within a 24-hour period.
Nasal Spray: 5 mg, 10 mg, or 20 mg. Dosage varies with product. Consult package instructions.
Children:
Use of sumatriptan in children under 18 years is generally not recommended as efficacy and safety have not been established.
Special Cases:
- Elderly Patients: Use with caution. Data in patients over 65 is limited.
- Patients with Renal Impairment: No dose adjustment is typically necessary.
- Patients with Hepatic Dysfunction: Mild to moderate impairment: Oral dose not to exceed 50 mg. No adjustment necessary for subcutaneous injection, but use with caution. Severe hepatic impairment: Contraindicated.
- Patients with Comorbid Conditions: Caution in patients with cardiovascular disease, uncontrolled hypertension, or ischemic heart disease.
Clinical Use Cases
Sumatriptan is specifically indicated for the acute treatment of migraine and cluster headache. It is not indicated for use in scenarios like intubation, surgical procedures, mechanical ventilation, or ICU use, unless specifically related to migraine or cluster headache management. It is not indicated for emergency situations like status epilepticus or cardiac arrest.
Dosage Adjustments
Dose adjustments are necessary for patients with hepatic dysfunction. See above under “Special Cases”.
Side Effects
Common Side Effects
Dizziness, tingling or numbness, flushing, drowsiness, weakness, fatigue, nausea, vomiting, dry mouth, injection site reactions (pain, redness).
Rare but Serious Side Effects
Myocardial infarction, stroke, seizures, serotonin syndrome, allergic reactions (anaphylaxis), coronary vasospasm, Prinzmetal’s angina, visual disturbances, hypertension.
Long-Term Effects
Medication overuse headache, development of tolerance.
Adverse Drug Reactions (ADR)
Any signs or symptoms of cardiac ischemia, neurological events, or allergic reactions.
Contraindications
Hypersensitivity to sumatriptan; history of myocardial infarction, stroke, ischemic heart disease, Prinzmetal’s angina, uncontrolled hypertension; peripheral vascular disease; Wolff-Parkinson-White syndrome; severe hepatic impairment; concomitant use of ergotamine derivatives or MAO inhibitors.
Drug Interactions
MAO inhibitors (increased risk of serotonin syndrome); ergotamine derivatives (additive vasoconstrictive effects); selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) (increased risk of serotonin syndrome); tricyclic antidepressants (increased risk of serotonin syndrome).
Pregnancy and Breastfeeding
Sumatriptan is categorized as Pregnancy Category C. Use only if the potential benefit justifies the potential risk to the fetus. It is excreted in breast milk. Caution is advised during breastfeeding.
Drug Profile Summary
- Mechanism of Action: 5-HT1B/1D receptor agonist, leading to vasoconstriction and inhibition of neuropeptide release.
- Side Effects: Dizziness, tingling, flushing, nausea, injection site reactions. Rarely: myocardial infarction, stroke.
- Contraindications: Cardiovascular disease, uncontrolled hypertension, severe hepatic impairment, concomitant use of ergotamine or MAO inhibitors.
- Drug Interactions: MAO inhibitors, ergotamine, SSRIs, SNRIs.
- Pregnancy & Breastfeeding: Category C; use with caution.
- Dosage: Adults: Oral: 25-100 mg; SC: 1-6 mg; Nasal spray: dose varies by product.
- Monitoring Parameters: Blood pressure, heart rate, neurological status.
Popular Combinations
Sumatriptan is sometimes combined with naproxen (a nonsteroidal anti-inflammatory drug) for enhanced pain relief.
Precautions
- General Precautions: Assess cardiovascular risk factors before initiating therapy. Monitor for signs of serotonin syndrome.
- Specific Populations: Pregnant women, breastfeeding mothers, and elderly patients: use with caution. Children: not recommended.
- Lifestyle Considerations: May impair ability to operate machinery or drive. Alcohol may exacerbate side effects.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Sumatriptan?
A: The recommended starting dose is 25 mg - 100 mg orally, 1 mg to 6 mg subcutaneously or nasal spray dosage will vary. Maximum daily dose is 200 mg orally, 12 mg subcutaneously. Specific maximum doses for nasal spray varies by product.
Q2: How quickly does Sumatriptan work?
A: Oral: 30-60 minutes. Subcutaneous injection: 10-15 minutes. Nasal spray: ~15 minutes.
Q3: Can Sumatriptan be used during pregnancy?
A: Pregnancy Category C. Use only if the benefit outweighs the risks.
Q4: What are the most common side effects of Sumatriptan?
A: Dizziness, tingling, flushing, nausea, and injection site pain/reactions.
Q5: What are the serious side effects to watch out for?
A: Chest pain, shortness of breath, weakness, changes in vision, neurological symptoms. Seek immediate medical attention if these occur.
Q6: Can Sumatriptan interact with other medications?
A: Yes. Significant interactions can occur with MAO inhibitors, ergotamine, SSRIs, and SNRIs. Inform patients to disclose all medications, including OTC and supplements.
Q7: Can Sumatriptan be used to prevent migraines?
A: No. Sumatriptan is for acute treatment only, not for prophylaxis.
Q8: How should Sumatriptan be administered?
A: Orally: swallow tablets whole with water. Subcutaneously: Inject into the thigh. Nasal spray: follow product-specific instructions.
Q9: What should patients do if they miss a dose?
A: Sumatriptan is taken as needed for acute attacks. There’s no scheduled dose to “miss.” Instruct patients to take a dose at the onset of migraine symptoms.
Q10: Is Sumatriptan addictive?
A: Sumatriptan is not considered addictive, but medication overuse headache can occur with frequent use. Limit use to no more than four migraine attacks per 30-day period.
