Lithium Treatment for Bipolar Disorder
For bipolar disorder, lithium is recommended as a first-line treatment with target serum levels of 0.6-0.8 mmol/L for maintenance therapy and 0.8-1.2 mmol/L for acute mania. 1, 2
Indications and Clinical Uses
Lithium is indicated for:
- Treatment of acute manic episodes
- Maintenance treatment to reduce frequency and intensity of episodes
- Prophylaxis of bipolar disorder
Effectiveness by Phase
- Acute Mania: Highly effective, normalizing symptoms within 1-3 weeks 2
- Maintenance Treatment: Strong evidence as first-line therapy 1, 3
- Bipolar Depression: Modest support, less robust evidence compared to other phases 4
- Suicide Prevention: Consensus across guidelines that lithium tangibly reduces suicide risk 5
Dosing Recommendations
Acute Mania
- Initial dose: 600 mg three times daily (t.i.d.)
- Target serum level: 1.0-1.5 mmol/L
- Monitoring: Serum levels twice weekly during acute phase until stabilized 2
Maintenance Treatment
- Typical dose: 300 mg three or four times daily (t.i.d. or q.i.d.)
- Target serum level: 0.6-0.8 mmol/L 1, 5
- Monitoring: Serum levels every 2 months during remission 2
Special Populations
- Elderly patients: Lower doses recommended as they may exhibit toxicity at levels normally tolerated by others 2
- Children and adolescents: Baseline and regular monitoring required, similar target levels as adults but may achieve therapeutic levels at lower doses 1, 5
Monitoring Requirements
Before Initiation
- Complete blood cell count
- Thyroid function tests
- Urinalysis
- Blood urea nitrogen, creatinine, and serum calcium levels
- Pregnancy test in females of childbearing potential 1
During Treatment
- Acute phase: Serum lithium levels twice weekly until stabilized
- Maintenance phase: Every 2-3 months
- Timing of blood draws: 8-12 hours after previous dose (trough levels) 2
- Renal and thyroid function: Every 3-6 months 1
Therapeutic Drug Monitoring
- Blood samples should be drawn immediately prior to the next dose (trough levels)
- Clinical evaluation must accompany laboratory analysis; don't rely solely on serum levels 2
- Higher serum concentrations (0.8-1.0 mmol/L) are more effective for maintenance but associated with more side effects 6
Safety Considerations
Cardiac Monitoring
- Lithium has been associated with T-wave changes, bradycardia, and AV-block 1
- Caution should be exercised in patients treated concomitantly with anti-arrhythmic drugs
Common Side Effects
- Tremor
- Diarrhea
- Urinary frequency
- Weight gain
- Metallic taste 6
Duration of Treatment
- Maintenance treatment should continue for at least 2 years after the last episode of bipolar disorder 1
- Decision to continue maintenance treatment beyond 2 years should preferably be made by a mental health specialist 1
Combination Therapy
- For bipolar depression, antidepressants (preferably SSRIs like fluoxetine) may be considered in combination with lithium 1
- SSRIs are preferred over tricyclic antidepressants when combined with lithium 1
Clinical Pitfalls to Avoid
- Inadequate monitoring: Failure to regularly check serum levels can lead to toxicity or subtherapeutic treatment
- Improper timing of blood draws: Samples must be drawn at trough levels (8-12 hours post-dose) for accurate assessment
- Relying solely on serum levels: Clinical assessment remains essential alongside laboratory values
- Discontinuing too early: Premature discontinuation increases relapse risk
- Ignoring drug interactions: Many medications can affect lithium levels
Lithium remains the gold standard for bipolar disorder treatment despite the introduction of newer agents. Its proper administration requires careful dosing, regular monitoring, and attention to patient-specific factors to balance efficacy with tolerability.