Extrapyramidal syndrome related to lithium-carbamazepine combination therapy at therapeutic serum levels.

Neurological disturbances due to lithium-carbamazepine combination therapy are infrequent, and only a few cases have been reported so far. We describe a most unusual case of a patient with a history of bipolar disorder who developed ataxic gait, imbalance, and intention tremor after lithium-and-carbamazepine combination treatment with therapeutic serum levels of both drugs; he recovered completely when carbamazepine was discontinued. We also review the literature about this infrequent relationship, discuss on its proposed origin, and underline its importance as a potential adverse effect in elderly patients, yet with therapeutic or even subtherapeutic serum levels.