BIOAVAILABILITY AND CENTRAL SIDE-EFFECTS OF DIFFERENT CARBAMAZEPINE TABLETS

  • 1 January 1985
    • journal article
    • research article
    • Vol. 23  (4) , 226-232
Abstract
The bioavailabilty and central side effects of 5 carbamazepine tablets [autoxomic drug] with different rates of absorption were investigated in 9 healthy volunteers in a randomized cross-over study using single doses of 400 mg. There were 7-fold differences in the peak times (Tmax), 1.5-fold differences in the peak serum concentrations (Cmax) but no significant differences in the total bioavailability (AUC [area under the concentration curve]0-96 h) of these tablets. On the tablets with the slowest absorption the serum concentrations were still, 24 h after the ingestion, more than 90% of the Cmax. Central side effects (dizziness, ataxia) were significantly (P < 0.01) more common when a brand of tablets with a rapid absorption was used. These tablets were characterized by a rapid dissolution in vitro in 0.1 N HCl. The total bioavailability of carbamazepine does not decrease despite moderate prolongation of the absorption phase. The pure AUC-data alone are inadequate to characterize the clinical equivalency of carbamazepine products. Formulations with a low absorption may be preferable: central side effects are less common and serum concentrations more constant.