The
serum levels of
lamotrigine can be increased by sodium
valproate. Small increases, decreases or no changes in sodium
valproate levels have been seen with
lamotrigine. Concurrent use has been associated with skin rashes and other toxic reactions.
Monitor the outcome of concurrent use. In patients already taking valproate, the manufacturer of
lamotrigine recommends a
lamotrigine starting dose that is half that of
lamotrigine monotherapy, irrespective of whether they are also receiving enzyme-inducing antiepileptics, and a very gradual dose-escalation rate. The development of rashes should be investigated promptly.