Effect of phenytoin, carbamazepine, and valproic acid on caffeine metabolism.

Three groups of non-smoking epileptic patients without liver disease receiving antiepileptic monotherapy have been compared with 10 healthy non-smoking volunteers. Group 1 received phenytoin (n = 10), Group 2 carbamazepine (n = 10) and Group 3 valproic acid (n = 6). Cytochrome P-450 activity was monitored by measuring urinary 6-beta-hydroxycortisol output and systemic antipyrine clearance.

Free level monitoring of carbamazepine and valproic acid: clinical significance.

The recently available ultrafiltration technique facilitates determination of the free drug serum concentration of several antiepileptic drugs. For this reason a reappraisal of the clinical significance of free level monitoring was thought necessary. In this study on 203 patients receiving carbamazepine monotherapy and 101 patients receiving valproic acid monotherapy, the total and free drug levels were correlated with therapeutic outcome and side effects.