Sumatriptan Data - Uses, Dosage, Drug class, Brand name, Warnings, etc

Pharmacology	Sumatriptan is a serotonin (5-HT) analogue and a selective agonist at 5-HT1D receptors in cerebral vascular smooth muscle. Receptor activation results in migraine relief by vasoconstriction of intracranial blood vessels and attenuation of the release of vasoactive peptides responsible for inflammation of sensory nerves.
Administration and Adult Dosage	For migraine treatment: - Oral (PO): 25–100 mg; a second dose of up to 100 mg may be administered in 2 hr if response is unsatisfactory. Additional doses may be given every 2 hr, up to 200 mg in a 24-hr period. A 100 mg dose might not provide greater effect than a 50 mg dose - Subcutaneous (SC): 6 mg; a second 6 mg injection may be administered 1 hr after the initial dose, limited to no more than 2 injections within a 24-hr period - Intranasal: 5–20 mg in one nostril or 5 mg in each nostril; may repeat in 2 hr to a maximum of 40 mg/day
Special Populations - Pediatric Dosage	(<18 yr) Safety and efficacy not established.
Special Populations - Geriatric Dosage	Same as adult dosage. Consider the possibility of undiagnosed heart disease in the elderly.
Dosage Forms	- Tablet: 25, 50 mg - Injection: 6 mg/0.5 mL - Nasal Spray: 5, 20 mg
Patient Instructions	- Use sumatriptan for relief of migraine, not for prevention - Do not take if pregnant without consulting a physician - Inform your physician if you have high blood pressure, diabetes, seizures, or heart, liver, or kidney disease - Report pain or tightness in chest, shortness of breath, wheezing, or rash immediately - Oral: Do not take more than 200 mg within 24 hours; allow at least 2 hours after the first tablet - SC Injection: Do not take more than 2 injections within 24 hours; allow at least 1 hour between injections. Pain or redness at injection site lasts less than 1 hour - Nasal Spray: If 1 dose does not provide adequate relief, take another dose after 2 hours; do not exceed 40 mg in 1 day
Pharmacokinetics - Onset and Duration	- Oral: 50% of patients respond in 2 hr; peak 1.5 hr - Subcutaneous: 70% of patients respond within 1 hr, 90% within 2 hr; peak 10–15 min - Intranasal: 50–60% of patients respond in 2 hr
Pharmacokinetics - Fate	- Bioavailability: • Oral: 14 ± 3% due to presystemic metabolism and erratic absorption; absorption delayed by ~0.5 hr with food • Subcutaneous: 97 ± 16% - Peak Serum Levels: • Oral (100 mg): 54 µg/L (180 nmol/L) at ~1.5 hr • Subcutaneous (6 mg): 74 µg/L (250 nmol/L) at 12 min • Intranasal (20 mg): 16 µg/L (54 nmol/L) - Protein Binding: 14–21% - Distribution: Vd = 2.7 L/kg - Clearance: Cl = 0.96 ± 0.12 L/hr/kg - Metabolism: Hepatic metabolism by MAO-A to an indole acetic acid, followed by glucuronidation - Excretion: ~40% in feces, 60% renally (22% unchanged, 40% as active indole acetic acid metabolite)
Pharmacokinetics - t¹⁄₂	- Elimination half-life: 1.9 ± 0.3 hr
Adverse Reactions & Side Effects	Frequent: - Subcutaneous: Pain and redness at injection site, tingling, hot flushes, dizziness, chest tightness or heaviness - Nasal Spray: Throat discomfort, unusual taste Occasional (all routes): - Weakness, myalgia, burning sensation, tightness in chest, transient hypertension, drowsiness, headache, numbness, neck pain, abdominal discomfort, mouth/jaw discomfort, sweating Rare: - Cardiac arrhythmias, myocardial ischemia, polydipsia, dehydration, dyspnea, skin rashes, dysuria, dysmenorrhea Other: - Long-term use: Accumulation in melanin-rich tissues (e.g., eye) - Rare reports of ischemic colitis
Contraindications	- Intravenous administration - Ischemic heart disease - Prinzmetal’s angina - Uncontrolled hypertension - Concurrent administration of MAO inhibitors or within 2 weeks of discontinuation - Within 24 hr of an ergotamine-containing drug or ergot derivative (e.g., methysergide, dihydroergotamine) - Hemiplegic or basilar migraine
Precautions & Warnings	- Use caution in pregnancy - Use with caution in patients with impaired hepatic function, seizure disorder, neurologic lesion, cardiovascular disease, postmenopausal women, or men >40 yr
Drug Interactions	- Nonselective MAO inhibitors or MAO-A inhibitors can increase systemic availability of sumatriptan, especially after oral administration - Ergot alkaloids (e.g., ergotamine, methysergide, dihydroergotamine) may cause prolonged vasospastic reactions if used together - SSRIs can cause weakness, hyperreflexia, and incoordination when given with sumatriptan and other triptans
Parameters to Monitor	- Renal, hepatic, and cardiovascular status initially and every 6 months
Class and Drug Brand Name	- Class: Analgesic and Anti-Inflammatory Drugs - Brand Name: Imitrex
Notes	- Subcutaneous sumatriptan is effective in the treatment of cluster headache and appears to be more effective than ergotamine/caffeine in aborting migraine - Subcutaneous administration is more expensive than alternatives - Not intended for migraine prophylaxis

References

Hand of Clinical Drug Data