Drugs for Movement Disorders

Question 1

What are the drugs used to treat Parkinson Disease (6)?

Answer 1

Levodopa, Carbidopa, Dopamine Agonists, MOAIs, COMT inhibitors, and anti-muscarinics

Question 2

Describe the MOA action and distribution of levodopa in the presence of carbidopa.

Answer 2

Dopamine cannot be given, because it will not cross the BBB. Levodopa is a dopamine precurso that can cross the BBB. Once it does, it is decarboxylated into dopamine.

levodopa is decarboxylated extracerebrally. To prevent this, levodopa is coadministered with carbidopa. Allowing for higher concentrations to enter the CNS.

Question 3

Describe the ADRs of levodopa. Which are suppressed with the co-administration of levodopa?

Answer 3

ADRs - N/V, anorexia, hypotension, behavioral changes, and dyskinesia (wearing-off and on-off phenomena)

N/V, anorexia, and hypotension can be relieved by carbidopa

Note: the dyskinesia phenomena occur with prolonged use of levodopa

Question 4

Describe the DDIs and CIs of levodopa

Answer 4

DDIs - MOAIs (hypertension); pyridoxine (increases levodopa metabolism)

CIs - Psychosis, melanoma, and angle-closure glaucoma

Question 5

Name the dopamine agonists used in the Tx of Parkinson disease. What are other uses of these drugs?

Answer 5

Bromocriptine and Pramipexole

Bromocriptine - prolactinemia

Pramipexole - restless legs syndrome

Question 6

What are the types of MAO’s? Which one is targeted in parkinson disease?

Answer 6

MAO-A = metabolizes NE, serotonin, and dopamine
MAO-B = metabolizes dopamine

MAO-B = targeted in Parkinson Disease

Question 7

What is the irreversible MAO-B inhibitor used in treatment of parkinson disease?

Answer 7

Rasagiline

Note: potential to cause hypertensive crisis in patients taking levodopa

Question 8

Describe the reasoning in using COMT inhibitors in the treatment of parkinson disease. What are the prototype COMT inhibitors?

Answer 8

Overtime, as levodopa and carbidopa are administered other routes for metabolism of levodopa develop. COMT is one of these mechanisms. COMT inhibitors can block this alternative metabolism.

Prototype - entacapone and tolcapone

Question 9

What are the uses of entacapone and tolcapone? What are associated ADRs?

Answer 9

Entacapone acts peripherally and tolcapone acts centrally and peripherally. These drugs are used to suppress response fluctuations

Tolcapone can cause acute elevations in hepatic enzymes

Question 10

What is the antimuscarinic used in treatment of parkinson disease? Describe related ADRs.

Answer 10

Benztropine - used for improving tremor and rigidity in parkinson disease

ADRs - systemic anti-muscarinic effects

Question 11

What drugs are used for the treatment of huntington disease?

Answer 11

Haloperidol, perphenazine, and olanzapine

Question 12

What drugs are used for the treatment of restless legs syndrome?

Answer 12

Dopamine agonists, levodopa, benzodiazepines, and opioids

Question 13

What drug is used for the treatment of Wilson disease?

Answer 13

penicillamine