What is the normal dosage of lithium (lithium carbonate) for suicide prevention?

Lithium Dosage for Suicide Prevention

For suicide prevention, lithium should be maintained at serum levels of 0.6-0.8 mmol/L for standard formulations, which typically requires 300 mg three to four times daily of lithium carbonate. 1, 2

Dosage Recommendations Based on Formulation

Standard-Release Formulations

• Initial dosing: 12-24 mmol (450-900 mg) per day, divided into 2-3 doses 3
• Maintenance dosing: 300 mg three to four times daily to maintain serum levels of 0.6-0.8 mmol/L 1, 2
• Administration schedule: Twice or three times daily dosing is recommended 3

Sustained-Release Formulations

• Target serum levels: 0.8-1.0 mmol/L 3
• Administration: Can be given once daily at night or twice daily 3

Age-Based Dosing Considerations

• <40 years: 25-35 mmol (925-1300 mg) daily 3
• 40-60 years: 20-25 mmol (740-925 mg) daily 3
• >60 years: 15-20 mmol (550-740 mg) daily 3

Monitoring Requirements

1. Acute phase: Serum lithium levels should be monitored twice weekly until stabilized 1
2. Maintenance phase: Monitor every 2-3 months 1, 2
3. Timing of blood draws: Samples should be drawn 12 hours after the last dose when lithium concentrations are relatively stable 2

Efficacy for Suicide Prevention

Lithium maintenance therapy has been associated with fewer suicidal behaviors and deaths in patients with unipolar depression or bipolar disorder 4. Studies have shown a suicide rate of 1.3 suicides per 1000 patient-years with lithium treatment compared to approximately 5.5 suicides per 1000 patient-years in untreated depression 5.

Important Clinical Considerations

• Therapeutic window: Lithium has a narrow therapeutic index, making regular monitoring essential 1
• Renal function: Lithium is primarily excreted by the kidneys, and renal insufficiency is a contraindication for lithium dose increases 1
• Treatment failure risk: Low lithium levels are associated with higher relapse rates, with one study showing 38% relapse at 0.4-0.6 mmol/L versus 13% relapse at 0.8-1.0 mmol/L 6
• Toxicity risk: Serum levels >1.5 mmol/L may have mild and reversible toxic effects; levels >2.0 mmol/L may cause neurological symptoms 7

Common Pitfalls to Avoid

• Inadequate monitoring: Failure to regularly check lithium levels can lead to subtherapeutic dosing or toxicity
• Medication non-adherence: This is the most common cause of low lithium levels 1
• Ignoring drug interactions: Many medications can decrease lithium clearance, increasing toxicity risk 3
• Overlooking special populations: Elderly patients and those with renal impairment require lower doses 1
• Relying solely on serum levels: Clinical evaluation must accompany laboratory monitoring 2

Lithium remains one of the most effective treatments for reducing suicide risk in patients with mood disorders when properly dosed and monitored, though its use requires careful consideration of individual patient factors and consistent therapeutic monitoring.