The
serum levels of
carbamazepine are usually only slightly affected by sodium valproate, valproic acid or valpromide although a moderate to marked rise in the levels of its active epoxide
metabolite may occur.
Carbamazepine may reduce the
serum levels of sodium
valproate by 60% or more. Concurrent use may possibly increase the
incidence of sodium valproate-induced hepatotoxicity.
Monitor
valproate levels, and adjust the dose if necessary. Also monitor for
carbamazepine toxicity (due to raised carbamazepine-epoxide levels), which may present as nausea, vomiting, ataxia or drowsiness.