What are the administration routes and dosages for sumatriptan (Imitrex) in treating migraine?

How to Administer Sumatriptan for Acute Migraine

Administer sumatriptan at migraine onset using subcutaneous 6 mg for fastest relief (15 minutes, 70-82% response), oral 50-100 mg for moderate attacks, or intranasal 5-20 mg when oral route is not feasible, with route selection based on attack severity and need for speed of relief. 1, 2

Route Selection Algorithm

Subcutaneous Administration (Fastest, Most Effective)

• Dose: 6 mg at onset, may repeat once after 1 hour if needed 1, 3
• Maximum: 12 mg per 24 hours 1, 2, 3
• Onset: Within 15 minutes with 70-82% response rate 1, 2
• Best for: Severe attacks, rapid nausea/vomiting, or when fastest relief is essential 2, 4
• Caveat: Injection site reactions occur in approximately 30% of patients 3, 5

Oral Administration (First-Line for Most Patients)

• Starting dose: 50 mg at onset when pain is still mild 2, 6, 7
• Alternative doses: 25 mg (less effective) or 100 mg (more adverse effects without significantly greater efficacy) 2, 6, 7
• May repeat after 2 hours if headache returns or partial response occurs 6, 7
• Maximum: 200 mg per 24 hours 1, 6, 7
• Efficacy: 50 mg provides pain-free response in approximately 28% vs 11% with placebo (NNT 6.1) 2, 8
• Important: The 50 mg dose provides optimal balance of efficacy and tolerability compared to other oral doses 2

Intranasal Administration

• Dose: 5-20 mg at onset, may repeat after 2 hours 1, 3
• Maximum: 40 mg per 24 hours 1, 3
• Best for: Patients with nausea/vomiting who cannot tolerate oral route 2
• Note: 20 mg intranasal provides headache relief with NNT 3.5 4

Critical Timing Considerations

Administer early when pain is still mild for optimal effectiveness—this significantly improves outcomes compared to waiting until pain is moderate or severe. 1, 4

Contraindications (Absolute)

• Coronary artery disease, previous MI, or Prinzmetal angina 1, 2, 3, 5
• Hemiplegic or basilar migraine 1, 3
• Uncontrolled hypertension 1, 2
• Current MAOI use or within 2 weeks of discontinuation 2, 3, 6
• Within 24 hours of ergotamine, DHE, or another triptan 1, 2, 3

Managing Inadequate Response

• Trial for 2-3 headache episodes before determining efficacy—single failure does not indicate treatment failure 1, 2, 3
• If one triptan fails, different triptans may still work for the same patient 1
• Headache recurrence occurs in approximately 40% within 8-12 hours and can be effectively treated with a second dose following minimum interval requirements 1, 9, 10

Medication Overuse Prevention

Limit sumatriptan use to maximum 2 days per week to prevent medication overuse headache—exceeding this frequency significantly increases risk. 2

• If using >2 days/week, consider preventive therapy 2
• Safety of treating >4 headaches per 30 days has not been established 6, 7

Special Populations

Hepatic Impairment

• Maximum single oral dose: 50 mg in mild-to-moderate hepatic impairment 6, 7
• Rationale: Hepatic disease causes unpredictable elevations in oral sumatriptan bioavailability 6

Common Adverse Effects

• Cardiovascular sensations (chest pressure, heaviness, warmth) occur in 3-5% and are generally benign 1, 2
• Subcutaneous route: injection site reactions in ~30% 3, 5
• Intranasal route: bitter taste at back of mouth is common 10
• Most adverse events are mild-to-moderate, transient, and self-limiting 4, 10

Critical Drug Interactions

• Mandatory 24-hour washout period between sumatriptan and ergotamine/DHE in either direction 1, 2
• Never combine with MAOIs due to unpredictable bioavailability elevations 2, 6

Red Flags Requiring Immediate Evaluation

Instruct patients to seek immediate care for chest pain suggestive of cardiac ischemia, neurological symptoms beyond typical aura, or severe hypertension. 2