Drug-induced Parkinsonism

Question 1

Differentiate idiopathic PD and Parkinsonism symptoms:

Answer 1

Parkinsonism:

• usually bilateral (VS PD - unilateral in early stages)
• more often in elderly
• acute/subacute (VS PD - chronic)
• reversible (VS PD - progressive)
• variable response to drug withdrawal
• poor response to levodopa
• other features: orofacial dyskinesia, akathisia
• tremor at rest is UNCOMMON
• more common in females (VS PD common in males)
• freezing is UNCOMMON

Question 2

Treatment of drug-induced Parkinsonism

Answer 2

Best treatment is PREVENTION

• Withdrawal of the drug leads to improvement in symptoms in 80% of pt in 8 weeks (but not always reversible)
• Treatment should be withdrawal of the offending drug

Drugs for symptom relief:

• Amantadine
• Anticholinergic

Question 3

Drugs with high potential to cause drug-induced parkinsonism

Answer 3

Dopamine D2 receptor blockers

• FGAs: Haloperidol, Prochloperazine, Amisulpride
• SGAs at higher dose: Risperidone, Olanzapine, Aripiprazole

Dopamine depleters

• Tetrabenazine

Dopamine synthesis blockers

• a-methyldopa

Calcium channel antagonist

• Flunarizine, Cinnarizine

Question 4

Drugs with intermediate potential to cause drug-induced parkinsonism

Answer 4

SGAs

• Ziprasidone

Antiepileptics

• Valproate (dcr DA turnover), Phenytoin, Levetiracetam

Antiemetics (dopamine antagonists)

• Prochlorperazine
• Metoclopromide

Mood stabilizers

• Lithium (dcr dopamine release, cause tremors)

Calcium channel antagonist

• Diltiazem, Verapamil

Question 5

Drugs with lower potential to cause drug-induced parkinsonism

Answer 5

SSRIs
TCAs
MAOIs
Antiarrthymics: amiodarone, procaine
Immunosuppressants: ciclosporin, tacrolimus