What is the best medication to start for a patient on lithium (lithium carbonate) experiencing tardive dyskinesia?

Management of Tardive Dyskinesia in Patients on Lithium

Deutetrabenazine (AUSTEDO) is the best medication to start for a patient on lithium experiencing tardive dyskinesia, as it has demonstrated significant improvement in tardive dyskinesia symptoms in clinical trials with a treatment effect of -1.9 points on the AIMS scale compared to placebo. 1

Understanding Tardive Dyskinesia in Lithium Users

While tardive dyskinesia (TD) is most commonly associated with antipsychotic medications, it can also occur with lithium therapy, though this is less common. Several case reports have documented lithium-induced tardive dyskinesia, even at therapeutic doses and as monotherapy 2, 3.

Key considerations:

• TD presents as involuntary movements primarily in the orofacial region but can affect any part of the body 4
• Lithium itself has been reported to both cause TD in some cases 5, 3 and potentially protect against TD in others 6
• The Abnormal Involuntary Movement Scale (AIMS) is the standard assessment tool for TD severity 4, 1

First-Line Treatment Options

VMAT2 Inhibitors

• Deutetrabenazine (AUSTEDO): FDA-approved for TD with strong evidence
  • Dosing: Start at 12 mg/day and increase at weekly intervals in 6 mg increments
  • Demonstrated significant improvement in AIMS scores in clinical trials
  • In clinical trials, 42% of patients were rated as "Much Improved" or "Very Much Improved" compared to 13% on placebo 1
  • Available in multiple strengths (12mg, 24mg, 36mg) for dose optimization

Management Algorithm

1. Confirm diagnosis and assess severity:

   • Use AIMS scale to document baseline severity
   • Rule out other movement disorders

2. Consider lithium management:

   • If clinically feasible, consider reducing lithium dose as some cases suggest lithium-induced TD may be dose-dependent 2
   • Monitor lithium levels and mood stability closely if dose is reduced
   • Do not discontinue lithium if it's effectively managing bipolar disorder

3. Initiate VMAT2 inhibitor therapy:

   • Start deutetrabenazine at 12 mg/day
   • Titrate by 6 mg weekly to optimal dose (typically 24-36 mg/day)
   • Assess response after 12 weeks of treatment 1

4. Monitor for improvement and side effects:

   • Reassess AIMS score every 4-6 weeks during titration
   • Continue monitoring lithium levels and efficacy for mood stabilization

Special Considerations

• Avoid anticholinergics: These medications may actually worsen TD symptoms, especially when used without coexisting drug-induced parkinsonism 4
• Electroconvulsive therapy (ECT): Should be considered only for severe cases where medications are ineffective or not tolerated, particularly in bipolar disorder 7
• Concurrent medications: There are conflicting reports regarding the safety of lithium with ECT, with reports of acute brain syndrome when used together 7

Monitoring Recommendations

• Regular AIMS assessments (every 3-6 months)
• Monitor lithium levels every 3-6 months
• Thyroid and renal function tests every 3-6 months for patients continuing lithium 7
• Body mass index monitoring if atypical antipsychotics are added to the regimen

Common Pitfalls to Avoid

• Misdiagnosis: Don't confuse TD with akathisia or withdrawal dyskinesia
• Inappropriate use of anticholinergics: These can worsen TD symptoms
• Abrupt discontinuation of lithium: This could destabilize mood and potentially worsen movement disorders
• Inadequate dose titration: VMAT2 inhibitors require careful titration for optimal effect

By following this approach, the management of tardive dyskinesia in patients on lithium can be optimized while maintaining mood stability.