Lithium Starting Dose
For acute mania in adults, initiate lithium carbonate at 600 mg three times daily (1800 mg/day total), targeting a therapeutic serum level of 1.0-1.5 mEq/L during the acute phase. 1
Adult Dosing Strategy
Initial Dosing for Acute Mania
- Start with 600 mg three times daily (1800 mg/day) for most adult patients, as this typically achieves therapeutic serum levels of 1.0-1.5 mEq/L needed for acute treatment 1
- The FDA-approved labeling provides this as the standard starting regimen for optimal patient response 1
- Alternative initial dosing of 12-24 mmol per day (approximately 450-900 mg) may be considered based on age and body weight, though this represents a more conservative approach 2
Age-Adjusted Starting Doses
- Patients <40 years: Consider starting at the full 1800 mg/day (600 mg TID) 1
- Patients 40-60 years: May start at 20-25 mmol/day (740-925 mg/day) 2
- Patients >60 years: Start at lower doses of 15-20 mmol/day (550-740 mg/day), as elderly patients often exhibit toxicity at levels tolerated by younger patients 1, 2
Pediatric Dosing (Ages 7-17 Years)
Weight-Based Approach
- Children <30 kg: Start at 300 mg twice daily (600 mg/day total) 3
- Children/adolescents ≥30 kg: Start at 300 mg three times daily (900 mg/day total) 3
- Increase by 300 mg/day weekly based on clinical response and tolerability 3
- An additional 300 mg increase during the first week may be appropriate for patients starting at 900 mg/day 3
Formulation Considerations
Standard-Release vs. Sustained-Release
- Standard-release formulations: Reach peak plasma concentration at 1-2 hours; maintain target levels of 0.6-0.8 mmol/L 2
- Sustained-release formulations: Peak at 4-5 hours; target slightly higher levels of 0.8-1.0 mmol/L due to reduced peak concentrations 2
- Sustained-release preparations reduce peak plasma concentrations by 30-50% without significantly changing total drug exposure 2
Dosing Frequency
- Initial phase: Administer in divided doses (2-3 times daily) to minimize adverse effects 1, 2
- Once stabilized: Single daily evening dosing may reduce long-term renal damage risk and improve compliance, though this is typically reserved for maintenance therapy 4, 5
Critical Monitoring Requirements
Acute Phase Monitoring
- Check serum lithium levels twice weekly until both levels and clinical condition stabilize 1, 6, 7
- Draw blood samples 8-12 hours after the last dose (trough levels) for accurate interpretation 1
- Monitor for signs of toxicity, as toxic effects can occur at doses close to therapeutic levels 7
Baseline Laboratory Assessment
Before initiating lithium, obtain: 6, 8
- Complete blood count
- Thyroid function tests (TSH, free T4)
- Renal function (BUN, creatinine, calculated GFR)
- Urinalysis
- Serum calcium
- Electrolytes
Important Safety Considerations
Contraindications and Cautions
- Renal insufficiency is a relative contraindication; if GFR <60 mL/min/1.73 m², use extreme caution or avoid 7, 8
- Avoid NSAIDs as they decrease lithium clearance and increase toxicity risk 7
- Elderly patients are particularly prone to neurotoxicity even at standard doses 7
Patient Education Priorities
- Educate patients about early signs of lithium toxicity (tremor, confusion, ataxia, nausea) 6
- Emphasize the importance of maintaining adequate hydration and consistent sodium intake 7
- Warn about the narrow therapeutic window—toxicity can occur at levels only slightly above therapeutic range 7
Transition to Maintenance Therapy
Once acute symptoms stabilize (typically after several weeks):