Litholent SR 400 Tablet contains lithium carbonate 400 mg as its active ingredient and is primarily indicated for the management of bipolar disorder, including the treatment and prophylaxis of manic and depressive episodes. Lithium carbonate is a mood stabilizer that modulates neurotransmitter activity and intracellular signaling pathways, thereby helping to stabilize mood swings and reduce the frequency and severity of manic episodes. The sustained-release formulation ensures a gradual release of lithium, maintaining therapeutic plasma concentrations over an extended period and minimizing peak-related side effects. Litholent SR 400 should be administered under strict medical supervision, with regular monitoring of serum lithium levels to avoid toxicity, as lithium has a narrow therapeutic index. Common adverse effects may include tremors, polyuria, mild gastrointestinal discomfort, and weight gain, while serious toxicity can manifest as neurological impairment, renal dysfunction, or cardiac arrhythmias. Caution is advised in patients with renal or cardiovascular disease, thyroid disorders, or those taking concomitant medications that may interact with lithium. Adequate hydration and electrolyte balance should be maintained during therapy. Litholent SR 400 is contraindicated in pregnancy and lactation unless the potential benefits outweigh the risks. Patient adherence and periodic clinical evaluation are essential for optimizing therapeutic outcomes and minimizing adverse effects.