How to Start Lithium Therapy
Begin lithium carbonate at 300 mg three times daily (900 mg/day total) for most adults, targeting a therapeutic serum level of 0.8-1.0 mEq/L for acute mania or bipolar disorder, with serum levels checked twice weekly until stabilized. 1
Initial Dosing Strategy
Standard Adult Dosing
- Start with 600 mg three times daily (1800 mg/day) for acute mania, which typically produces effective serum lithium levels between 1.0-1.5 mEq/L 1
- For maintenance therapy or less acute situations, initiate at 300 mg three or four times daily (900-1200 mg/day), targeting levels of 0.6-1.2 mEq/L 1
- The usual maintenance dose ranges from 925-1300 mg daily for patients under 40 years, 740-925 mg for ages 40-60, and 550-740 mg for those over 60 2
Special Population Adjustments
- Elderly patients require lower starting doses of 150 mg/day due to increased sensitivity and reduced lithium clearance 3
- For patients with GFR < 60 mL/min/1.73 m², use lower doses with more frequent monitoring 3
- Reduce dose by 50% when GFR < 30 mL/min/1.73 m² 3
Pre-Treatment Baseline Testing
Complete the following laboratory assessments before initiating lithium:
- Complete blood count 3
- Thyroid function tests (TSH, free T4) 3
- Renal function (BUN, creatinine, GFR) 3
- Serum electrolytes including calcium 3
- Urinalysis 3
- Baseline ECG (particularly in elderly or those with cardiac risk factors)
Contraindications to Screen For
Do not initiate lithium in patients with:
- Significant renal impairment (GFR < 30 mL/min/1.73 m² is a relative contraindication) 3
- Severe cardiovascular disease 3
- Severe dehydration or sodium depletion 3
- Concurrent NSAID use (increases lithium levels and toxicity risk) 3
Monitoring Protocol
Acute Phase (First 4-6 Weeks)
- Draw serum lithium levels twice weekly until both the level and clinical condition stabilize 1
- Obtain levels 8-12 hours after the previous dose (trough levels) for accurate interpretation 1
- Monitor for early side effects: tremor, diarrhea, urinary frequency, metallic taste 4
Maintenance Phase
- Check serum lithium levels at least every 2 months in stable patients 1
- Monitor renal function and electrolytes twice annually 3
- Continue thyroid function monitoring periodically 3
Target Therapeutic Levels
For Acute Mania
- Target 1.0-1.5 mEq/L during acute treatment 1
- Some patients exhibit toxicity at 1.0-1.5 mEq/L, requiring dose reduction 1
For Maintenance Therapy
- Maintain levels between 0.8-1.0 mEq/L for optimal relapse prevention 4
- The standard range of 0.6-1.2 mEq/L is acceptable, but levels of 0.8-1.0 mEq/L are 2.6 times more effective at preventing relapse compared to 0.4-0.6 mEq/L 4
For Augmentation of Antidepressants
- Lower levels of 0.2-0.6 mEq/L may be adequate when augmenting antidepressants 3
- Start with 600-900 mg/day and adjust based on response 5
- Low-dose augmentation (300-450 mg/day, achieving levels around 0.33 mEq/L) can be effective and well-tolerated 6
Dosing Schedule Considerations
- Once-daily evening dosing with sustained-release formulations is acceptable and may improve compliance 2
- Standard formulations are typically given 2-3 times daily 2
- Sustained-release preparations reduce peak plasma concentrations by 30-50% and should target the upper therapeutic range (0.8-1.0 mEq/L) 2
Critical Patient Education Points
- Maintain adequate hydration at all times, especially during illness 3
- Avoid NSAIDs (ibuprofen, naproxen) as they significantly increase lithium levels 3
- Report signs of toxicity immediately: severe tremor, confusion, vomiting, diarrhea, muscle weakness
- Understand that abrupt discontinuation increases relapse risk and should be avoided 7
Common Pitfalls to Avoid
- Do not rely solely on serum levels; clinical assessment is essential alongside laboratory values 1
- Do not increase doses during the first 4 weeks of therapy 1
- Avoid concurrent medication changes during lithium initiation when possible 7
- Remember that elderly patients often show toxicity at levels tolerated by younger patients 1