Lithium carbonate is the drug of choice for the management of bipolar disorder, but 20% to 40% of patients do not exhibit adequate response to this agent. Moreover, adjunctive therapy with tricyclic antidepressants and monoamine oxidase inhibitors (for depression) and neuroleptics (for mania) is widely prescribed in most lithium clinics. These agents, however, may precipitate or exacerbate the subsequent phase of the illness. More recently, carbamazepine, an anticonvulsant drug, has shown promise in the management of bipolar illness. Used either alone or in combination with lithium, carbamazepine has been associated with a response rate of approximately 65% in more than 500 patients enrolled in controlled and uncontrolled studies. The drug's antimanic effects have been clearly demonstrated, but its antidepressant effects must undergo further examination. Other anticonvulsants (such as valproate) appear highly effective. The high-potency benzodiazepines (such as clonazepam) and calcium channel blockers (such as verapamil) are also being evaluated in this patient population.