pharmokinetics
Last reviewed 01/2018
At the recommended dose of 6mg given subcutaneously or 100mg given orally, peak plasma concentrations of sumatriptan are achieved at 10 minutes (72 microgrammes per litre) and 1.5 hours (54 microgrammes per litre).
- bioavailability:
- 90% after subcutaneous administration
- 14% after oral administration
- 14-21% of sumatriptan is protein-bound
- metabolism:
- sumatriptan is transformed in the liver to an inactive indoleacetic acid metabolite that is excreted predominantly in the urine, although oral administration increases faecal excretion.
- elimination half-life is about 2 hours.
- effectiveness:
- subcutaneous 6mg dose
- 70-77% of patients improved within 1 hour - 81-86% of patients improved within 2 hours
- oral 100mg dose
- 75% of patients reported relied of headache and other symptoms within 4 hours.
- headache recurred in up to 44% of patients, within 24-48 hours, although it was treated effectively in up to 74% of patients by a second 100mg dose.