Lithium carbonate is a mood-stabilizing agent and the gold standard treatment for bipolar disorder. It is a monovalent cation that is chemically similar to sodium and potassium. Its precise mechanism in mood stabilization is complex and not fully understood, but it is believed to involve modulation of neurotransmitter systems, second messenger pathways, and neuroprotective effects. In the Indian context, it is a critical, cost-effective mainstay for long-term management of bipolar affective disorder and prophylaxis of recurrent manic episodes.
Adult: Initial: 300-600 mg/day in divided doses (e.g., 400 mg at night). Titrate based on serum levels and response. Typical maintenance: 900-1200 mg/day (often given as 400 mg two or three times daily). MUST be individualized based on TDM.
Note: Administer with or immediately after food to minimize GI upset. Swallow tablet whole with a full glass of water. Maintain consistent fluid intake (1.5-2.5 L/day) and normal dietary salt intake. Dosing is usually 2-3 times daily, but slow-release formulations allow once-daily dosing.
The exact mechanism is multifactorial and incompletely elucidated. It is believed to modulate signal transduction pathways by inhibiting inositol monophosphatase and glycogen synthase kinase-3 beta (GSK-3β). This leads to reduced recycling of inositol, dampening hyperactive neuronal signaling. It also affects neurotransmitter release (reducing dopamine and noradrenaline, increasing serotonin), enhances neuroprotective factors like BDNF, and may stabilize circadian rhythms.
Pregnancy: Pregnancy Category D (US FDA). Use in first trimester is associated with a 1-2% risk of Ebstein's cardiac anomaly. Use in later trimesters can cause neonatal goiter, hypothyroidism, floppy infant syndrome, and polyhydramnios. Use ONLY if the benefit outweighs the significant risk, typically in severe bipolar disorder where relapse poses a greater danger. Dose requirements may increase during pregnancy and drop precipitously after delivery. Close monitoring of levels is vital.
Driving: May impair alertness, especially at treatment initiation, during dose changes, or if toxicity develops. Patients should be cautioned against driving or operating machinery if they experience drowsiness, dizziness, blurred vision, or tremor.
| Diuretics (especially Thiazides, e.g., Hydrochlorothiazide) | Reduce renal clearance of lithium, leading to increased serum levels and toxicity. | Major |
| NSAIDs (e.g., Ibuprofen, Diclofenac, Celecoxib) | Reduce renal clearance, increase lithium levels. Risk is high with chronic use. | Major |
| ACE Inhibitors (e.g., Enalapril, Ramipril) / ARBs (e.g., Losartan) | Can increase lithium levels by reducing renal excretion. | Major |
| SSRIs/SNRIs (e.g., Sertraline, Fluoxetine, Venlafaxine) | Increased risk of serotonin syndrome and may potentiate lithium's neurotoxic effects. | Moderate |
| Antipsychotics (e.g., Haloperidol, Risperidone) | Increased risk of extrapyramidal symptoms (EPS) and neurotoxicity (encephalopathy). | Moderate |
| Metronidazole | May increase lithium levels, risk of toxicity. | Moderate |
| Theophylline, Aminophylline | Increase renal clearance of lithium, decreasing its serum levels and efficacy. | Moderate |
| Sodium Bicarbonate | May increase renal excretion of lithium, reducing levels. | Minor |
Same composition (Lithium carbonate (400mg)), different brands: