Sumatriptan
Sumatriptan. 5-HT1B/1D agonist — constricts cranial blood vessels and inhibits trigeminal nerve neuropeptide release. First-line abortive… Oral half-life 1.8 h.
5-HT1B/1D agonist — constricts cranial blood vessels and inhibits trigeminal nerve neuropeptide release. First-line abortive migraine therapy. Coronary vasoconstriction concern in CAD. SC formulation has fastest onset (~10 min).
PK: ROUTE ATTRIBUTION WAS SCRAMBLED, THOUGH THE NUMBERS WERE RIGHT. Its oral row cited a PROPRANOLOL INTERACTION study at a 300 mg dose that never mentions bioavailability or volume; both are verbatim in a paper already in this record references — "The mean subcutaneous bioavailability is 96% compared to 14% for the oral tablet" and "a large apparent volume of distribution (170 l)". The oral half-life of 1.8 h does verify there and is correctly the sumatriptan-alone arm rather than the propranolol one. CLASS 6 IS CLEARED BY PHYSIOLOGICAL REDUCTIO: were 170 L an apparent volume it would imply a true volume of 24 L, impossible for this drug, so pairing it with either bioavailability is right. MY OWN PREMISE THAT ITS ABSORPTION PARAMETER WAS DOING THE WRONG JOB IS REFUTED — "The lower bioavailability following oral administration is due mainly to presystemic metabolism", so the loss correctly lives in F and the record SHAPE is sound. Both ka values fail: the oral one is dose-mismatched, since absorption rate is the single nonlinear parameter in this drug, and the subcutaneous 3 implies a 49-minute peak against a measured 15 minutes, making the injection three times slower than it is. The intranasal route is declared with no parameters at all and is removed; the one paper covering all four routes is entirely qualitative.
Pharmacokinetics
- Oral — t½ 1.8 h · F 14% · Vd 170 L
- Subcutaneous — t½ 2 h · F 96% · Vd 170 L
Sources: PMID:7768259, PMID:8757005, PMID:1328844, PMID:10193663, PMID:27613076