Meropenem and other carbapenems appear to dramatically and rapidly reduce
valproate levels resulting, in some cases, in increased seizure frequency.
It would be prudent to monitor
valproate levels in any patient given carbapenems. The
valproate dosage may need to be increased. Consider using another antibacterial, or an alternative to
valproate. Limited evidence suggests that
carbamazepine and
phenytoin are not affected.