Addition of lamotrigine to valproate may enhance efficacy in the treatment of bipolar affective disorder.

The new antiepileptic lamotrigine has been shown to be effective in the treatment of focal epilepsies with or without secondary generalization and has also been suggested to be efficacious in the treatment and prophylaxis of affective disorders. Therefore, we analyzed its possible benefit in a patient with refractory bipolar affective disorder. Lamotrigine (up to 150 mg/d) was added to valproate (2700 mg/d), substituting previously administered neuroleptics. A considerable improvement of the patient's condition was achieved several days after the beginning of lamotrigine co-administration, and lasted over the total follow-up period of more than one year. The plasma concentrations after total remission were in the range of 1.9 to 6.2 mg/l for lamotrigine and 57.1 to 95.2 mg/l for valproate. This positive action of lamotrigine is discussed in the context of the drug's elementary effects on sodium and calcium channels.