Usual Adult Dose for Migraine:
Use only after a clear diagnosis of migraine has been established
Oral:
Initial dose: 25 mg, 50 mg, or 100 mg orally, once
-If some response to first dose occurs, a second dose may be administered at least 2 hours after first dose if needed
-Oral doses of 50 and 100 mg may provide greater relief than 25 mg; however, a 100 mg dose may not provide greater effect than a 50 mg dose
Maximum dose: 200 mg per 24 hours
Intranasal:
Nasal spray: Initial dose: 5 mg, 10 mg, or 20 mg into one nostril, once
-Administer the 5 and 20 mg doses as a single spray in 1 nostril; the 10 mg dose may be administered as 5 mg into each nostril
-If some response to first dose occurs, a second dose may be administered at least 2 hours after first dose if needed
Maximum dose: 40 mg per 24 hours
Comments:
-Treatment should be started at the first sign of a migraine headache, or associated symptoms such as nausea, vomiting, or photophobia; this drug should not be used for migraine prophylaxis.
-Higher doses may have a greater effect, but also carry a greater risk of adverse reactions.
-The safety of treating an average of more than 4 headaches in a 30 day period has not been established.
Use: For the acute treatment of migraine with or without aura.
 Detailed Imitrex dosage information
What happens if I miss a dose?
Since Imitrex is used when needed, it does not have a daily dosing schedule. Call your doctor if your symptoms do not improve after using this medicine.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include tremors, skin redness in your arms or legs, weakness, loss of coordination, breathing problems, blue-colored lips or fingernails, vision problems, or a seizure (convulsions).
