II. Pathophysiology
- Typically caused by antipyschotic agents, which may over-blockade Dopaminergic Receptors
- Results in excess Cholinergic Activity due to a loss of typical Dopamine-mediated inhibition
III. Symptoms
-
Akathisia
- Motor restlessness
- Differentiate medication side effect from mania or Anxiety Disorder
- Parkinsonian Effects (longstanding Antipsychotic use)
- Shuffling gait
- Cogwheel rigidity
- Psychomotor retardation
-
Dystonias
- Involuntary major Muscle Contractions
- Acute laryngospasm may occur
- Spasmodic Torticollis (spasm of neck Muscles, esp. sternocleidomastoid Muscle)
- Oculogyric Crisis (eyes fixed, staring upward or rolling back in head)
IV. Causes: Extrapyramidal Side Effects - Antipsychotics
- Haloperidol (Haldol) or Haloperidol Decanoate
- Perphenazine (Trilafon)
- Thiothixene HCl (Navane)
- Fluphenazine HCl (Prolixin)
- Trifluoperazine (Stelazine)
- Risperidone (Risperdal)
V. Causes: Tardive Dyskinesia
-
Antipsychotics
- Longterm use of high dose, high potency agents (e.g. Haloperidol)
- Atypical Antipsychotics
- Other medications (esp. Dopamine blockers)
- Antiparkinsonism agents (e.g. Levodopa)
- Metoclopramide (Reglan)
- Anticonvulsants (e.g. Phenytoin)
- Antidepressants
- Tricyclic Antidepressants (e.g. Amitriptyline)
- Serotonin Reuptake Inhibitors or SSRI (e.g. Fluoxetine, Sertraline)
VI. Adverse Effects: Reversible Extrapyramidal signs and symptoms
- Conditions responsive to anti-Parkinsons Agents
-
Neuroleptic Malignant Syndrome
- Presents as Catatonia, fever, unstable Blood Pressure
- Life-threatening; Stop Antipsychotic immediately
VII. Adverse Effects: Irreversible (Tardive Dyskinesia)
- Evaluate for these signs monthly while on Antipsychotic (see prevention as below)
- Higher risk in elderly, cardiovascular disease risk, HIV Infection, neurologic disorders
- Tardive Dyskinesia
- Hyperkinesia (lingual or facial)
- Blinking
- Lip smacking
- Sucking or chewing
- Rolls or protrudes Tongue
- Grimaces
- Choreoathetoid extremity movement
- Clonic jerking fingers, ankles, toes
- Tonic contractions of neck or back
- Hyperkinesia (lingual or facial)
VIII. Management
- Reversible Extrapyramidal Effects
- Tolerance to affect
- Decrease or Increase OR discontinue drug dose
- Shift patient to an agent without Extrapyramidal Side Effects
- Anticholinergic Agents may decrease Dystonia or Parkinsonism effects
- Consider Beta Blockers for Akathisia
- Tardive Dyskinesia
- Lower dose or discontinue medication
- Consider Clozapine as alternative Antipsychotic
- Avoid adding Anticholinergic Agent (e.g. Benztropine)
- May worsen Tardive Dyskinesia (despite benefit in acute Dystonia)
- Reversible Vesicular monoamine transporter 2 Inhibitors (VMAT2)
- Deutetrabenazine (Austedo)
- Ingrezza (Valbenazine)
- Decreases Dopamine in nerve endings
- Reduces symptoms by 50% with 6 weeks of treatment (Number Needed to Treat: 4)
- Very expensive ($5000 per month)
- Other symptomatic management
- Vitamin E supplementation
- Vitamin B6 Supplementation
- Amantadine
- Lower dose or discontinue medication
IX. Prevention
- Clinicians should be alert for Extrapyramidal Side Effects (and modify therapy to reduce adverse effects)
- Perform Abnormal Involuntary Movement Scale (AIMS) at least every 6 months while on Antipsychotic Medications
X. References
- (2017) Presc Lett 24(6): 36
- Mason, Swadron and Herbert in Herbert (2019) EM:Rap C3 3(2): 8