First-pass effect after rectal administration of thiazinamium methylsulfate.
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.
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
D008725:Bis-Trimethylammonium Compounds; D001993:Bronchodilator Agents; D013488:Suppositories; D011398:Promethazine