Metabolic studies of delta-9-tetrahydrocannabinol in cancer patients.
The metabolism of oral delta-9-tetrahydrocannabinol (THC) was studied in nine patients with gastrointestinal neoplasms receiving chemotherapy regimens containing 5-FU and semustine. Plasma levels of THC and its metabolites 11-OH-delta-9-THC (11-OH-THC) and 11-nor-9-carboxy-delta-9-THC (C-THC) were measured. Plasma levels of THC and its metabolites were quite variable among the patients studied. Plasma levels of THC and 11-OH-THC tended to peak at the same time; the C-THC levels peaked later and lasted much longer than the others. Mean half-lives of THC, 11-OH-THC, and C-THC were estimated to be 1.5, 2.1, and 4.4 hours, respectively. Multiple doses of THC did not produce a significant additive effect on the plasma concentrations of the biologically active metabolites THC and 11-OH-THC. No correlation between antiemetic effect or cannabinoid toxicity and plasma levels of the three metabolites could be made in this small number of patients.
D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D013759:Dronabinol / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism* / Q000627:therapeutic use; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D005770:Gastrointestinal Neoplasms / Q000097:blood / Q000188:drug therapy*; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008113:Liver Neoplasms / Q000097:blood / Q000188:drug therapy / Q000556:secondary; D008297:Male; D008875:Middle Aged; D012673:Semustine / Q000008:administration & dosage
D012673:Semustine; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol; D005472:Fluorouracil