title: First-pass effect after rectal administration of thiazinamium methylsulfate.
abstract: The absorption and metabolism of the quaternary ammonium compound thiazinamium methylsulfate were studied in humans using plasma concentration data and urinary excretion measurements. After giving a dose of 150 mg in suppositories, the relative bioavailability was 5.8 +/- 3.2 (SD) % of the dose, comparable to the values obtained following oral administration. The degree of first-pass effect observed after rectal administration was comparable with that after oral administration.
mesh_terms: D000368:Aged; D001682:Biological Availability; D001711:Biotransformation; D008725:Bis-Trimethylammonium Compounds / Q000008:administration & dosage / Q000378:metabolism; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011398:Promethazine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000378:metabolism; D012007:Rectum; D013488:Suppositories
chemical_list: D008725:Bis-Trimethylammonium Compounds; D001993:Bronchodilator Agents; D013488:Suppositories; D011398:Promethazine