The comparative bioavailability of carbamazepine in 100 mg and 200 mg tablets.

1. The bioavailabilities of carbamazepine in 100 mg and 200 mg tablets have been compared in a cross-over study of six subjects after two 600 mg doses of the drug, the different preparations being taken at 3 week intervals. 2. Areas under the plasma level curves, absorption rate constants and times to achieve peak plasma levels showed little difference between the two preparations. These findings suggest similar rates and extents of bioavailability of carbamazepine in the two preparations. 3. Calculated mean absorption and elimination parameters for carbamazepine were as follows: kabs = 0.1081 h-1, (s.d. = 0.0289); Tmax = 23.39 h, (s.d. = 8.66); k = 0.0191 h-1, (s.d. = 0.0033); VD = 0.989 1/kg, (s.d. = 0.159); and clearance = 0.0185 1/kg h, (s.d. = 0.0015).