Lamotrigine, another anticonvulsant medication, received FDA approval for the long-term maintenance treatment of bipolar I disorder in 2003; it and lithium are the only two medications that currently have this designation. It has been shown to delay the recurrence of episodes of mood disturbance (mania, hypomania, mixed, and depressed). Where lamotrigine may have the greatest benefit is in the treatment of the depression associated with bipolar disorder.
Lamotrigine is metabolized in the liver and mostly excreted through the urine. Its half-life when taken alone is approximately twenty-five hours. This is greatly influenced when other medications are added that can either increase or decrease its rate of metabolism in the liver.
The average dose in the treatment of bipolar disorder is between 100–200mg/day. Unlike other medications which can be tapered up rapidly, it is recommended that lamotrigine be increased slowly; this has been shown to decrease the incidence of serious skin rashes. The recommended schedule is: 25mg for two weeks, then increase to 50mg for two weeks, then 100mg for a week and then as directed by your physician.