Low biological availability of ergotamine tartrate after oral dosing in cluster headache.
An attempt was made to determine the plasma ergotamine concentrations in nine male patients with cluster headache 15-600 min after oral therapeutic doses of ergotamine tartrate (Cafergot). Some of the patients were studied twice. Five patients received a constant dose of 2-4 mg daily for at least seven days. Four patients were given 1 mg five times on one day and three patients a single oral dose of 2 mg. Ergotamine was determined by means of high performance liquid chromatography with fluorescence detection--a new highly sensitive, specific method, the detection limit of which is less than 100 pg/ml for ergotamine. Ergotamine tartrate was not discovered in any of the plasma samples. In one patient ergotamine could not be detected in the cerebrospinal fluid one hour after a single oral dose of 2 mg. The oral biological availability is less than 1%, which is the maximal available fraction of unchanged ergotamine after oral administration. A clinical benefit was observed in several of our patients. These effects of the drug may be because of active metabolites being formed and/or to high affinity of ergotamine to cranial vessels.
D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D003027:Cluster Headache / Q000188:drug therapy / Q000378:metabolism*; D004878:Ergotamine / Q000097:blood / Q000378:metabolism; D004879:Ergotamines / Q000008:administration & dosage / Q000378:metabolism* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D014653:Vascular Headaches / Q000378:metabolism*
D004879:Ergotamines; D004878:Ergotamine