Parkinson Drugs

Question 1

L-DOPA + carbidopa (Sinemet)

Answer 1

Class: antiparkinsonian: dopamine precursor + peripheral decarboxylase inhibitor.
Apps: treat Parkinson’s.
Effects: dyskinesia, choreiform rxn and dystonic rxn after >3 yrs treatment, orthostatic hypotension

Question 2

Ropinirole

Answer 2

Class: antiparksinon- non-ergot alkaloid dopamine D2/D3 agonist
Apps: treat Parkinson’s, both as early monotherapy and in combo w/ L-DOPA in advanced disease. Also restless leg.
Mech: motor improvement effects attributed to D2 actions. Unknown relevance of D3 even though binding affinity D3>D2.
Effects: nausea/vomiting, dizziness, postural hypotension, lower extremity edema, hallucinations

Question 3

Pramipexole

Answer 3

Class: antiparkinsonian- non-ergot alkaloid D2/D3 agonist.
Apps: for Parkinson’s as early monotherapy and in combo w/ L-DOPA in advanced disease.
Mech: motor improvement effects attributed to D2 actions. Unknown relevance of D3 even though binding affinity D3>D2.
Effects: nausea/vomiting, dizziness, postural hypotension, lower extremity edema, hallucinations

Question 4

Apomorphine

Answer 4

Class: potent D1 & D2 agonist
Apps: manage sudden, levodopa-induced ‘off’ states in fluctuating Parkinson’s via rescue injections or continuous infusion.
Mech: D1 & D2 agonist
Effects: mild cutaneous rxns, neuropsyciatric. Increased rxns for continuous infusions.

Question 5

Amantadine

Answer 5

Class: antiparkinsonian; syntehtic antiviral later found to help Parkinson’s.
Apps: use for mild Parkinson’s, early monotherapy.
Mech: block DA reuptake, actions on glutamate receptors (as NMDA receptor agonist).
Effects: CNS rxns (dizziness, anxiety, impaired coordination), hyperkinesia, nausea, vomiting; livedo reticularis

Question 6

Benzotropine

Answer 6

Class: muscarinic antagonist; antiparkinsonian agent
Apps: help control tremor but less effective for treating bradykinesia or rigidity.
Mech: reduced excessive cholinergic activity present in parkinsonism. Block dopamine reuptake.
Effects: minor unless overdose- xerostomia, anhidrosis, constipation, blurred vision, cycloplegia, mydriasis, urinary retention.

Question 7

Trihexyphenidyl

Answer 7

Class: muscarinic antagonist; antiparkinsonian agent
Apps: help control tremor but less effective for treating bradykinesia or rigidity.
Mech: reduced excessive cholinergic activity present in parkinsonism. Block dopamine reuptake.
Effects: minor unless overdose- xerostomia, anhidrosis, constipation, blurred vision, cycloplegia, mydriasis, urinary retention.

Question 8

Selegiline

Answer 8

Class: irreversible MAO-B inhibitor for Parkinson’s.
Apps: adjunct treatment for Parkinson’s.
Mech: irreversibly inhibit MAO-B.
Effects: high doses- nausea/vomiting, hallucinations, confusion, mental depression, loss of balance, insomnia, orthostatic, dyskinesias, dizziness

Question 9

Rasagiline

Answer 9

Class: irreversible MAO-B inhibitor for Parkinson’s.
Apps: adjunct treatment for Parkinson’s.
Mech: irreversibly inhibit MAO-B. More potent than selegiline; may have neuroprotective effects.
Effects: high doses- GI dysfunction, anorexia.

Question 10

Entacapone

Answer 10

Class: selective inhibitor of peripheral catechol-O-methyltransferase (COMT).
Apps: adjunct for Parkinson’s; used only in combo with L-DOPA/carbidopa
Mech: inhibit COMT increases AUC for a given L-DOPA dose.
Effects: dyskinesia, nausea/vomiting, hyperkinesia, diarrhea due to potentiating dopaminergic effects.