How to manage ongoing excessive jaw chewing in a patient on a low dose of quetiapine (antipsychotic)?

Management of Excessive Jaw Chewing in a Patient on Low-Dose Quetiapine

The excessive jaw chewing in a patient on low-dose quetiapine is most likely tardive dyskinesia, and switching to another atypical antipsychotic or reducing/discontinuing quetiapine should be considered as first-line management.

Understanding the Symptom

Excessive jaw chewing in a patient taking quetiapine (even at low doses) strongly suggests tardive dyskinesia (TD), which is characterized by involuntary, repetitive movements, often affecting the orofacial region. While quetiapine is considered to have a lower risk of extrapyramidal symptoms compared to typical antipsychotics, it can still cause TD.

Diagnostic Considerations

Before proceeding with treatment, consider:

• Duration of symptoms (TD typically develops after months or years of antipsychotic use)
• Ruling out other causes:
  • Akathisia (inner restlessness manifesting as movement)
  • Acute dystonia (sudden muscle contractions)
  • Parkinsonism (tremor, rigidity)
  • Primary movement disorders

Management Algorithm

Step 1: Assess and Document

• Use a standardized rating scale like the Abnormal Involuntary Movement Scale (AIMS) to document baseline severity 1
• Determine if symptoms are causing significant distress or functional impairment

Step 2: Medication Management

1. First-line approach: Consider discontinuation or dose reduction of quetiapine

   • If clinically feasible, gradually taper and discontinue quetiapine 1
   • If quetiapine is essential for psychiatric stability, reduce to lowest effective dose 1

2. Alternative medication options:

   • Switch to clozapine (most evidence for TD improvement) 2
   • Consider other atypical antipsychotics with lower TD risk if needed for psychiatric symptoms
   • Avoid typical antipsychotics which have higher risk of worsening TD 1

3. Adjunctive treatments if discontinuation is not possible:

   • Valbenazine or deutetrabenazine (VMAT2 inhibitors FDA-approved for TD)
   • Amantadine (mild dopaminergic agent) for symptomatic relief 1
   • Benzodiazepines may provide temporary relief of symptoms 1

Step 3: Non-pharmacological Approaches

• Relaxation techniques to reduce overall muscle tension
• Speech therapy focusing on jaw relaxation exercises
• Cognitive behavioral strategies to reduce focus on the movements

Special Considerations

1. Risk factors that may worsen prognosis:

   • Older age
   • Female gender
   • Longer duration of antipsychotic exposure
   • Higher cumulative antipsychotic dose

2. Monitoring:

   • Regular AIMS assessments (every 3-6 months) 1
   • Monitor for worsening of psychiatric symptoms if medication is changed

Evidence for Quetiapine in TD

Interestingly, while quetiapine can cause TD, there is some evidence that it may actually improve TD in some cases. Case reports have shown that quetiapine can reduce TD symptoms when used to replace other antipsychotics 2, 3. One case series demonstrated improvement in SSRI-induced bruxism and mandibular dystonia with low-dose quetiapine (25-50 mg daily) 4.

However, the primary approach should still be to reduce or discontinue the causative agent when possible, as TD can become permanent with continued exposure to antipsychotics 1.

Pitfalls to Avoid

1. Don't mistake TD for worsening psychiatric symptoms - The restlessness and movements of TD can be misinterpreted as agitation related to the underlying psychiatric condition

2. Don't abruptly discontinue quetiapine - This can lead to withdrawal symptoms including nausea, vomiting, and rebound psychosis 5

3. Don't add anticholinergic medications - While these may help acute dystonia, they can worsen TD 1

4. Don't ignore TD symptoms - Early intervention improves prognosis; TD can become permanent if the causative medication is continued long-term 1