What is the initial treatment for acute parkinsonism?

Acute Parkinsonism Treatment

For drug-induced acute parkinsonism (extrapyramidal symptoms from antipsychotics), treat acute dystonia immediately with anticholinergic medications, while parkinsonism and akathisia require either dose reduction of the offending agent, switching antipsychotics, or adding specific symptomatic treatments. 1

Immediate Management Based on Symptom Type

Acute Dystonia (Most Urgent)

• Administer anticholinergic medication immediately for sudden spastic muscle contractions affecting the neck, eyes (oculogyric crisis), or torso 1
• Dystonic reactions can be life-threatening when laryngospasm occurs and typically respond well to anticholinergic or antihistaminic medications 1
• Young males using high-potency antipsychotics are at highest risk 1

Drug-Induced Parkinsonism (Bradykinesia, Tremor, Rigidity)

The American Psychiatric Association suggests three options 1:

• Lower the antipsychotic dosage (first-line approach)
• Switch to another antipsychotic medication (particularly to an atypical agent with lower D2 blockade)
• Add an anticholinergic medication (benztropine, trihexyphenidyl) or amantadine 1

Critical distinction: Differentiate drug-induced parkinsonism from negative symptoms of schizophrenia or catatonia, as these require different management 1

Akathisia (Severe Restlessness)

The American Psychiatric Association recommends 1:

• Lower the antipsychotic dose if clinically feasible (first-line)
• Switch to another antipsychotic with lower propensity for akathisia
• Add a benzodiazepine for symptomatic relief
• Add a beta-adrenergic blocking agent (propranolol)

Pitfall: Akathisia is commonly misinterpreted as psychotic agitation or anxiety, leading to inappropriate dose escalation rather than reduction 1

Parkinson's Disease Crisis (Acute Akinetic Crisis)

Emergency Dopaminergic Restoration

• Administer levodopa via nasogastric tube using crushed immediate-release carbidopa/levodopa at the patient's usual total daily dose divided into frequent intervals if oral intake is impossible 2
• Give levodopa at least 30 minutes before enteral nutrition, interrupting tube feeding for 1 hour before and 30-40 minutes after medication 2

Medications to AVOID in Crisis

• Never administer typical or atypical antipsychotics during Parkinson's crisis, as dopamine D2 receptor blockade produces severe rigidity and can precipitate neuroleptic malignant syndrome (NMS) 2
• Avoid dopamine-blocking antiemetics (metoclopramide, prochlorperazine) 2
• Do not use benzodiazepines as primary treatment, though they may be considered for severe agitation only after dopaminergic therapy is restored 2
• Do not use anticholinergic agents (benztropine, trihexyphenidyl) as primary treatment for acute rigidity in crisis, as they provide minimal benefit for severe akinesia and worsen confusion 2

Critical Monitoring

• Monitor for aspiration pneumonia, as dysphagia worsens during crisis 2
• Watch for hyperthermia, rhabdomyolysis, and autonomic instability if NMS is suspected 2
• Distinguish Parkinson's crisis from NMS: NMS presents with fever (often >38.5°C), severe rigidity, altered mental status, and elevated creatine kinase, whereas Parkinson's crisis typically lacks fever unless infection is the precipitant 2

Prophylactic Considerations for Drug-Induced Parkinsonism

• Consider prophylactic antiparkinsonian agents when initiating high-potency antipsychotics in patients at risk for acute dystonias or with prior dystonic reactions 1
• This is particularly important in paranoid patients where compliance may be compromised by distressing extrapyramidal symptoms 1
• Reevaluate the need for antiparkinsonian agents after the acute phase or if antipsychotic doses are lowered, as many patients no longer require them during long-term therapy 1

Dosing Specifics for Anticholinergic Treatment

For drug-induced parkinsonism requiring anticholinergic therapy 3:

• Trihexyphenidyl initial dose: 1 mg on day one
• Titrate by 2 mg increments every 3-5 days
• Total daily dose range: 5-15 mg for extrapyramidal reactions (some patients controlled with as little as 1 mg daily)
• Divide into 3-4 doses: Take at mealtimes, with fourth dose at bedtime if needed
• Adjust timing based on side effects: Take after meals if excessive salivation is problematic; take before meals if dry mouth is the issue

Warning: Abrupt withdrawal of antiparkinsonian treatment may result in acute exacerbation of symptoms or neuroleptic malignant syndrome 3