Tox: Parkinsons drugs

Question 1

6 types of anti-parkinsonian drugs

Answer 1

1) Levodopa
2) dopamine agonists (e.g. bromocriptine, pramipexole, ropinirole)
3) catechol-o-methyltransferase (COMT) inhibitors (e.g. entacapone)
4) MAO B inhibitors
5) Amantidine
6) Anti-cholinergics (e.g. benztropine)

Question 2

Mechanism of tox of parkinson drugs

Answer 2

1) Levodopa/dopamine agonists: XS activation of dopaminergic neurons, activation of serotonergic systems.
2) COMT/MAOBis: XS circulating catecholamines.
3) Amantadine/antichol: inhibition of central/peripheral muscarinic receptors.

Question 3

Symptoms of levodopa/dopamine tox

Answer 3

Acute toxicity: anxiety, confusion, agitation, tachy, orthostatic hypoTN, n/v, dyskinesias.

Chronic: dystonia, hallucinations, hypersexuality, delusions, fibrotic changes (with dopamine agonists)

Question 4

Symptoms of amantadine/antichol OD

Answer 4

Essentially anticholinergic toxidrome

Question 5

Potential complication of discontinuation of parkinson drugs

Answer 5

NMS! if dopaminergic agents are stopped