Pharmacokinetics of triamterene.
The knowledge about the pharmacokinetics of triamterene (TA) was limited until recently. The metabolic pathway of TA is the formation of p-hydroxytriamterene (OH-TA), which is subsequently conjugated with active sulfate to form p-hydroxytriamterene sulfuric acid ester (OH-TA-ester). The phase-II-metabolite is surprisingly pharmacologically active. TA and its metabolites were measured by a specific and sensitive tlc-method concomitantly. The i.v. kinetics of TA were determined after application of a newly developed lactic acid solution of the drug. Comparing these data with results after oral application of TA the bioavailability of TA was 52% and the extent of absorption 83%. The bioavailability of different dosage forms was correlated with in vitro tests. In liver disease the pharmacokinetics of TA are markedly altered. While in cirrhosis the hydroxylation of TA was decreased, the biliary excretion of this agent was strongly reduced in hepatitis. In renal disease the excretion of TA and OH-TA-ester was reduced according to endogenous creatinine clearance. In older patients the elimination of TA was impaired.
D000367:Age Factors; D000368:Aged; D001682:Biological Availability; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007674:Kidney Diseases / Q000378:metabolism*; D007700:Kinetics; D008107:Liver Diseases / Q000378:metabolism*; D013997:Time Factors; D014223:Triamterene / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism* / Q000652:urine
C026475:hydroxytriamterene sulfate ester; D014223:Triamterene