Lithium Starting Dose for Bipolar Disorder
For acute mania, start lithium carbonate at 600 mg three times daily (1800 mg/day total), targeting serum levels of 1.0-1.5 mEq/L, with twice-weekly monitoring until stabilization. 1
Acute Mania Dosing Protocol
Initial dose: 600 mg three times daily (1800 mg/day) is the FDA-approved starting regimen that typically produces effective serum lithium levels between 1.0-1.5 mEq/L for acute mania 1
Alternative initial dosing can start at 450-900 mg per day (12-24 mmol) depending on age and body weight, then titrate upward to reach therapeutic levels 2
Target serum level for acute mania: 0.8-1.2 mEq/L is recommended by the American Academy of Child and Adolescent Psychiatry, with some protocols targeting 1.0-1.5 mEq/L during the acute phase 3, 1
Serum levels should be checked twice weekly during the acute phase until both serum level and clinical condition stabilize 1
Maintenance Dosing After Stabilization
Maintenance target: 0.6-1.2 mEq/L with typical dosing of 300 mg three to four times daily (1200-1600 mg/day total) 1
Higher maintenance levels (0.8-1.0 mEq/L) are significantly more effective than lower levels (0.4-0.6 mEq/L), with relapse risk 2.6 times higher in the low-range group, though side effects increase at higher levels 4
Monitor serum lithium levels every 3-6 months during maintenance therapy in uncomplicated cases 5, 1
Age-Specific Dosing Adjustments
Patients <40 years: 925-1300 mg daily (25-35 mmol) for maintenance 2
Patients 40-60 years: 740-925 mg daily (20-25 mmol) for maintenance 2
Patients >60 years: 550-740 mg daily (15-20 mmol) for maintenance, as elderly patients often exhibit toxicity at levels ordinarily tolerated by younger patients 1, 2
Dosing Schedule Considerations
Once-daily dosing is preferred over multiple daily doses to reduce renal adverse effects (particularly urinary frequency), improve compliance, and potentially minimize long-term renal damage, without compromising efficacy 6, 7
Twice-daily dosing requires higher total daily doses and produces more urinary frequency compared to once-daily administration 7
Blood samples for serum lithium determination should be drawn 8-12 hours after the previous dose when concentrations are relatively stable 1
For once-daily administration, the serum concentration at 24 hours should serve as the control value 2
Critical Monitoring Requirements
Baseline assessment must include: complete blood count, thyroid function tests, urinalysis, blood urea nitrogen, creatinine, serum calcium levels, and pregnancy test in females 5, 3
Ongoing monitoring every 3-6 months: lithium levels, renal function, thyroid function, and urinalysis 5, 3
Monitor for signs of toxicity (confusion, tremor, ataxia) that could occur even at therapeutic doses, particularly in elderly patients 8, 1
Common Pitfalls to Avoid
Do not rely solely on serum levels - accurate patient evaluation requires both clinical and laboratory analysis 1
Patients abnormally sensitive to lithium may exhibit toxic signs at serum levels of 1.0-1.5 mEq/L that are therapeutic for others 1
Avoid NSAIDs in patients on lithium, as they can affect drug metabolism and increase toxicity risk 8
Ensure adequate hydration to prevent toxicity, as dehydration significantly increases lithium levels 5
Renal insufficiency is a contraindication to lithium use, especially if sodium-poor diet is required 2