Clinical pharmacokinetics and oral bioavailability of ketobemidone.
The basic pharmacokinetics and oral bioavailability of ketobenmidone have been studied in 6 patients after surgery. Plasma concentrations were first determined following intravenous administration of Ketogin 2 ml, containing ketobemidone chloride 10 mg and the spasmolytic N,N-dimethyl-3,3-diphenyl-1-methylallylamine chloride 50 mg, and then, on the second postoperative day, following oral administration of 2 tablets of Ketogin, each containing ketobemidone chloride 5 mg and the spasmolytic agent 25 mg. The average oral bioavailability of ketobemiodone was 34% +/- 16% (SD, n = 6). The mean plasma half-life of elimination (t1/2 beta) was about the same following oral (2.45 +/- 0.73 h; SD, n = 5) as after intravenous administration (2.25 +/- 0.35 h; SD, n = 6). The low oral bioavailability and rapid elimination of ketobemidone demonstrated in this study suggest that the usual dosage recommendation for oral Ketogin (ketobemidone 5--10 mg every 6--7 h) in patients with severe pain is too low.
D000284:Administration, Oral; D000328:Adult; D000499:Allylamine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000378:metabolism; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000378:metabolism*; D001682:Biological Availability; D004338:Drug Combinations / Q000008:administration & dosage / Q000378:metabolism; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007275:Injections, Intravenous; D007700:Kinetics; D008297:Male; D008614:Meperidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism; D008875:Middle Aged
D000701:Analgesics, Opioid; D004338:Drug Combinations; D000499:Allylamine; C010597:ketobemidone, N,N-dimethyl-3,3-diphenyl-1-methylallylamine drug combination; D008614:Meperidine; C012394:ketobemidone