Lamotrigine and lithium in mood stabilization Review article

Abstract

Bipolar disorder (BD) is a chronic mental disorder characterized by recurrent episodes of depression and mania or hypomania. The mainstay of treatment for BD is long-term mood-stabilizing pharmacotherapy, which aims to prevent relapses and reduce symptom severity. Classic first-generation mood stabilizers include lithium, valproate, and carbamazepine, while second-generation mood stabilizers include atypical antipsychotics and lamotrigine. Lithium has remained the standard treatment for BD for decades, particularly in the prevention of manic episodes and reducing the risk of suicide. However, its use is limited by its narrow therapeutic index, the risk of toxicity, and the need for regular laboratory monitoring, including renal and thyroid function. Lamotrigine, initially used as an antiepileptic drug, has found a permanent place in the treatment of bipolar disorder, particularly in preventing recurrence of depressive episodes in type I and II depression. Its mechanism of action is based on inhibiting sodium channels and limiting glutamate release, which promotes the stabilization of neuronal activity. In clinical trials, it demonstrated high antidepressant efficacy in maintenance treatment, with limited antimanic effects. Lamotrigine has a more favorable tolerability and safety profile than lithium. It does not significantly affect renal or thyroid function, does not cause significant metabolic disturbances, and is associated with a lower risk of toxicity in overdose. Although there is a small risk of severe skin reactions, appropriate, gradual individual dose titration significantly reduces this risk. In summary, lithium and lamotrigine differ in their efficacy and safety profiles. Lithium remains crucial for the prevention of mania and suicide, while lamotrigine is a particularly valuable option for patients with predominant depressive polarity, enabling safe and well-tolerated long-term therapy.