Can Risperidone (antipsychotic medication) cause Extrapyramidal Symptoms (EPS)?

Risperidone and Extrapyramidal Symptoms (EPS)

Yes, risperidone can cause extrapyramidal symptoms (EPS), with the risk being dose-dependent and occurring even at lower doses, though generally less frequently than with conventional antipsychotics. 1, 2

Types of Extrapyramidal Symptoms Associated with Risperidone

Risperidone can cause several types of extrapyramidal symptoms:

• Acute dystonia: Sudden spastic contractions of muscle groups, often affecting the neck, eyes (oculogyric crisis), or torso. These reactions can be distressing and potentially life-threatening in cases of laryngospasm 3

• Parkinsonism: Symptoms including bradykinesia, tremors, and rigidity that mimic Parkinson's disease 3, 1

• Akathisia: A sense of severe restlessness often manifesting as pacing or physical agitation, commonly misinterpreted as psychotic agitation or anxiety 3, 1

• Tardive dyskinesia: Involuntary movement disorder consisting of athetoid or choreic movements, typically in the orofacial region but potentially affecting any part of the body 3

Risk Factors and Incidence

The FDA label for risperidone provides clear evidence of dose-related EPS:

• In fixed-dose trials, EPS incidence increased with higher doses:

  • 7% at 1 mg/day
  • 12% at 4 mg/day
  • 17% at 8 mg/day
  • 18% at 12 mg/day
  • 20% at 16 mg/day 1

• Parkinsonism scores similarly increased with dose:

  • 0.6 at 1 mg/day
  • 1.7 at 4 mg/day
  • 2.4 at 8 mg/day
  • 2.9 at 12 mg/day
  • 4.1 at 16 mg/day 1

• Discontinuation rates due to EPS-related adverse events in clinical trials were approximately 3.4% 1

Comparison to Other Antipsychotics

• Risperidone causes fewer EPS than conventional antipsychotics like haloperidol, but more than other atypical antipsychotics like clozapine 4

• The American Academy of Child and Adolescent Psychiatry notes that risperidone at doses above 2 mg per day has an increased risk of EPS compared to lower doses 5

• QT prolongation data shows risperidone has minimal effect (0-5 ms) compared to other antipsychotics, which may be relevant when considering overall safety profile 3

Monitoring and Management

• Regular monitoring for EPS is essential, with the Abnormal Involuntary Movement Scale (AIMS) recommended at least every 3-6 months after starting therapy 3, 5

• For acute EPS management:

  • Consider dose reduction when clinically feasible 3
  • Anticholinergic medications are helpful for dystonia and parkinsonism 3
  • Beta-blockers and benzodiazepines may provide relief for akathisia 3
  • Prophylactic antiparkinsonian agents may be considered in high-risk patients 3

• The need for antiparkinsonian agents should be reevaluated after the acute phase of treatment or if doses are lowered 3

Clinical Implications

• EPS symptoms can significantly impact medication adherence and quality of life 6

• A case series demonstrated that EPS can develop from 1 week to 2 years after starting risperidone, with higher doses producing EPS earlier and lower doses later 6

• Susceptible individuals may experience dystonic symptoms during the first few days of treatment, with males and younger age groups at elevated risk 1

• Children and adolescents may be at higher risk for EPS than adults 3

• Patients with severe baseline EPS are at higher risk of developing EPS during risperidone treatment 2

In conclusion, while risperidone offers advantages over conventional antipsychotics regarding EPS risk, careful monitoring and dose optimization remain essential to minimize these potentially serious adverse effects.