Overview
Lithium carbonate is a mood-stabilizing agent primarily used for the treatment of bipolar I disorder. It is indicated for acute manic and mixed episodes as well as maintenance therapy in patients aged 7 years and older. Therapeutic use requires careful monitoring due to a narrow therapeutic index and risk of toxicity.
Mechanism of Action
Lithium's exact mechanism of action in bipolar disorder is not fully understood but is believed to involve modulation of neurotransmitter systems. It may affect second messenger systems by inhibiting inositol monophosphatase and glycogen synthase kinase-3, leading to changes in neuronal signaling and gene expression that stabilize mood.
Indications
- Treatment of acute manic and mixed episodes in bipolar I disorder in patients 7 years and older
- Maintenance treatment of bipolar I disorder in patients 7 years and older
Common Doses
- 150 mg
- 300 mg
- 600 mg
Dosage
Dosage must be individualized based on serum lithium concentrations, clinical response, and tolerability. Therapeutic serum levels typically range from 0.6 to 1.2 mEq/L for acute mania and 0.6 to 1.0 mEq/L for maintenance therapy. Regular monitoring of serum lithium levels, renal function, and thyroid function is required.
Contraindications
- Known hypersensitivity to any inactive ingredient in lithium carbonate capsules
Side Effects
- Tremor
- Polyuria
- Polydipsia
- Weight gain
- Cognitive impairment
- Gastrointestinal disturbances
- Hypothyroidism
- Renal dysfunction
- Lithium toxicity (≥1.5 mEq/L) with symptoms including diarrhea, vomiting, drowsiness, muscular weakness, and lack of coordination
Interactions
- Diuretics (especially thiazides) increase lithium reabsorption and risk of toxicity
- NSAIDs may increase lithium levels
- ACE inhibitors and ARBs may increase lithium concentrations
- Serotonergic drugs increase risk of serotonin syndrome
- Methyldopa, phenytoin, and carbamazepine may increase neurotoxic effects
Counseling Points
- Maintain consistent fluid and salt intake
- Report signs of lithium toxicity immediately (diarrhea, vomiting, tremor, drowsiness, muscle weakness)
- Regular blood tests are essential for monitoring lithium levels and organ function
- Avoid dehydration and excessive sweating
- Do not change dosage without medical supervision
- Be aware of potential drug interactions, especially with NSAIDs and diuretics
- Report pregnancy or plans to become pregnant to healthcare provider