[Calcium antagonists and lithium in preventive treatment of manic-depressive disorder]

Recent advances in knowledge about calcium's role as an intracellular regulator allow to broaden understanding of possible pathophysiologic mechanisms in affective disorders. An hypothesis emerge that bipolar illness arise from disorders in calcium-regulated functions. Given this hypothesis, some authors propose to describe the common profiles of action of the different mood-stabilizers: all the neural mechanisms that are hypothesized to explain various psychopharmacological treatments of bipolar illness involve functions that are critically controlled by calcium. Moreover, in every instance, a known action of lithium on calcium-dependent processes could account for lithium's prophylactic results. Similarities exist between the action of lithium and calcium antagonists like verapamil and nimodipine. From these considerations the hypothesis emerge that calcium antagonists could be an alternative pharmacological agent in the maintenance treatment of bipolar illness. Calcium antagonists have been found useful in this indication by a number of investigators. Given the safety and relative lack of side effects of calcium channel blocking agents, their potential efficacy in mood disorders, it is concluded that calcium antagonists may be an alternative choice in prophylactic treatment for bipolar illness, especially in patients who cannot be treated with lithium or carbamazepine. There is evidence for using verapamil at 240 to 320 mg a day, in 2 to 4 times. Some studies suggest that the association of lithium with calcium antagonist resulted more effective than lithium alone or calcium antagonist alone in the reduction of episodes of affective disorders. However, concomitant administration of a calcium channel antagonist and lithium present adverse interactions (lithium toxicity, cardiovascular accidents), probably because of synergistic toxic effects. Therefore, authors advise care in monitoring patients receiving the combination of these medications.