Gabapentin and lamotrigine in bipolar disorder.

The utility of gabapentin and lamotrigine for the treatment of bipolar disorder is reviewed. Bipolar disorder is characterized by extreme mood fluctuations, including mania, hypomania, depression, and mixed episodes. Extrapolation of postulated mechanisms of anticonvulsant activity in bipolar disorder has led to the use of the newer anticonvulsants gabapentin and lamotrigine for therapy. Both agents appear promising on the basis of limited (often anecdotal) evidence. They may prove effective in patients with difficult cases of bipolar disorder, such as patients with rapid cycling, mixed episodes, and illness refractory to other treatments. Lamotrigine may offer a much-needed treatment alternative for bipolar depression and could be found effective for acute mania, but the need for slow dosage adjustment and the risk of rash may limit overall clinical utility. Gabapentin may offer significant advantages for acute mania: The dosage can be adjusted rapidly, adverse effects are generally minimal, the therapeutic index is high, there is no required laboratory monitoring, and there is minimal potential for interactions with other psychotropics. Until the results of randomized controlled trials are known, however, these two agents should be reserved for patients with bipolar disorder unresponsive to traditional therapies and for patients who cannot tolerate traditional agents. Preliminary evidence indicates that gabapentin and lamotrigine may be useful for the treatment of bipolar disorder.