Lithium Carbonate Tablet Strengths
Lithium carbonate tablets are available in 150 mg, 300 mg, and 600 mg capsule strengths, with extended-release formulations available in 300 mg and 450 mg tablets. 1
Standard Formulations
- Immediate-release capsules come in three strengths: 150 mg, 300 mg, and 600 mg 1
- These capsules contain lithium carbonate USP with inactive ingredients including colloidal silicon dioxide, gelatin, sodium lauryl sulfate, and talc 1
Extended-Release Formulations
- Extended-release tablets are available in 300 mg (Lithobid) and 450 mg (Eskalith CR) strengths 2
- Extended-release formulations produce 30-50% reductions in peak plasma concentrations compared to immediate-release forms, with peak concentrations occurring at 4-5 hours versus 1-2 hours for standard-release 3
- The 450 mg extended-release tablets are specifically designed for twice-daily dosing to improve compliance during maintenance therapy 4
Critical Dosing Considerations
Never split lithium tablets to achieve desired doses, as this creates inconsistent dosing that makes therapeutic monitoring unreliable and dangerous. 5, 6
- Lithium toxicity begins at serum levels of 1.5 mEq/L and serious toxicity occurs at >2.0 mEq/L, making precise dosing essential 5, 6
- The narrow therapeutic range (0.6-1.2 mEq/L for maintenance) requires use of appropriate tablet strengths rather than splitting 1, 3
Special Population Dosing
- Elderly patients requiring lower starting doses (e.g., 150 mg/day) should use the 150 mg capsule strength rather than splitting higher-strength tablets 5
- Patients with renal impairment (GFR <60 mL/min/1.73 m²) requiring dose reductions should use lower-strength tablets, with 50% dose reduction needed for GFR <30 mL/min/1.73 m² 5, 7
Standard Dosing Regimens
- Acute mania: Typical dosing is 600 mg three times daily (using 300 mg or 600 mg tablets), targeting serum levels of 1.0-1.5 mEq/L 1
- Maintenance therapy: Usually 300 mg three to four times daily (using 300 mg tablets), targeting serum levels of 0.6-1.2 mEq/L 1, 3
- The usual maintenance daily dose ranges from 925-1300 mg for patients <40 years, 740-925 mg for ages 40-60 years, and 550-740 mg for patients >60 years 3