Which drug is used to treat manic episodes in bipolar disorder?

Lithium is widely recognized as one of the primary treatments for bipolar disorder, particularly for managing manic episodes. It works by stabilizing mood and reducing the frequency and severity of mood swings. Lithium is thought to affect neurotransmitter systems in the brain, leading to a mood-stabilizing effect. It is unique in its ability to treat acute mania and prevent future episodes, making it a cornerstone of therapy in bipolar disorder management.

Other medications, such as fluoxetine, gabapentin, and sertraline, are not first-line treatments for acute mania. Fluoxetine and sertraline are selective serotonin reuptake inhibitors (SSRIs) primarily used to treat depression and anxiety disorders, and while they may be helpful for the depressive phases of bipolar disorder, they can potentially exacerbate manic symptoms if used alone. Gabapentin is primarily prescribed for neuropathic pain and seizures and does not have a strong indication in the treatment of bipolar mania. Thus, lithium stands out as the most appropriate choice for treating manic episodes in this context.