Pharmacokinetics, metabolism, and renal excretion of articaine and its metabolite articainic acid in patients after epidural administration.

Articaine is metabolized into articainic acid. The half-lives of articaine are 0.54 +/- 0.05 and 2.44 +/- 0.30 h and that of its metabolite, 2.44 +/- 0.30 h. Of the administered dose approximately 2-5% is excreted unchanged, 40-70% is excreted as articainic acid, and 4-15% as articainic acid glucoronide. The percentage of the total dose recovered in the urine varies between 50% and 91%. Protein binding of articaine in patients varies between 50% and 70%, and that of articainic acid between 60% and 90%. Renal clearance of articaine varies between 12 and 28 ml min-1, while that of articainic acid is between 84 and 160 ml min-1.