Summary
Carbamazepine (Tegretol®) was administered orally to four patients as a single dose, and one week later three times daily for 15–21 days. The plasma half-lives of the drug were shorter in all patients after multiple doses (20.9±5.0 hours) than after the initial single dose (35.6±15.3 hours). During multiple doses the plasma concentrations of the metabolite carbamazepine-10,11-epoxide followed those of the parent drug. The steady-state plasma concentrations expected during multiple doses were calculated from the pharmacokinetic parameters obtained in the single dose studies. The calculated levels were higher (17.2±7.2 µg/ml) than the observed maximal concentrations (8.4±1.6 µg/ml on day 4), which were obtained 3–4 days after starting the multiple doses. The levels tended to decrease further during the experimental period. The results suggest that carbamazepine induces its own metabolism in man.
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Eichelbaum, M., Ekbom, K., Bertilsson, L. et al. Plasma kinetics of carbamazepine and its epoxide metabolite in man after single and multiple doses. Eur J Clin Pharmacol 8, 337–341 (1975). https://doi.org/10.1007/BF00562659
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DOI: https://doi.org/10.1007/BF00562659