Anti- Parkinson Drugs

Question 1

What is the effect of a lesion in the extra pyramidal motor path?

Answer 1

Tremor at rest; Rigidity

Question 2

What is the pathogenesis of Parkinson’s?

Answer 2

Loss of dopamine-secreting cells in the pars compact of the substantia nigra.

Question 3

What are some iatrogenic causes of Parkinson’s?

Answer 3

Drugs that reduce dopamine activity.

Question 4

Why do haloperidol and phenothiazines cause PD?

Answer 4

They block DA receptors.

Question 5

Why do reserpine and tetrabenzine cause PD?

Answer 5

They deplete brain monoamines from storage sites.

Question 6

Why does manganese poisoning cause PD?

Answer 6

It accumulates in the substantial nigra and interferes with enzyme systems. Oxidizes DA.

Question 7

True or false: In PD the DA system is severely compromised and the cholinergic system operates unopposed?

Answer 7

True. Treatment thus involves restoring balance.

Question 8

What does L-DOPA do?

Answer 8

It is a dopaminergic drug (precursor of DA) that increases DA activity.

Question 9

Can L-DOPA cross the BBB?

Answer 9

Yes.

Question 10

What is the response rate to L-DOPA and is it safe to use?

Answer 10

Response rate is high; Generally safe.

Question 11

What are the adverse effects of L-DOPA?

Answer 11

Nausea, confusion

Question 12

What does Carbidopa do?

Answer 12

Inhibits decarboxylase activity in the periphery. This prevents conversion of L-DOPA to DA.

Question 13

Can Carbidopa cross the BB?

Answer 13

No.

Question 14

How does Entacapone work?

Answer 14

It is a COMT inhibitor. Adjunct with L-DOPA. Entacapone prolongs L-DOPA action. Acts peripherally to reduce L-DOPA metabolism.

Question 15

How does Tolcapone work?

Answer 15

COMT inhibitor. Acts peripherally and centrally.

Question 16

What are the adverse effects of Tolcapone?

Answer 16

Can be hepatotoxic.

Question 17

How does Amantadine work?

Answer 17

Enhances endogenous DA. It acts on release/synthesis/reuptake.

Question 18

True or false: Amantadine is also an anti-viral agent for the A2 influenza.

Answer 18

True.

Question 19

How does Bromocriptine work?

Answer 19

Agonist to D2 and partial antagonist to D1 receptors.

Question 20

True or false: Bromocriptine has a longer duration of action that L-DOPA.

Answer 20

True.

Question 21

When is Bromocriptine used?

Answer 21

Used as an adjunct in late treatment. Combats on/off effect.

Question 22

How does Pergolide work?

Answer 22

Agonist to D1 and D2 receptors. More potent than Bromocriptine.

Question 23

True or false: Pergolide has a longer duration of action that L-DOPA and less on/off effect.

Answer 23

True.

Question 24

How does Pramipexole work?

Answer 24

It is a DA agonist (D3). Used as adjunct with L-DOPA.

Question 25

When is Pramipexole used?

Answer 25

When the PD is mild.

Question 26

True or false: Pramipexole is possibly neuroprotective.

Answer 26

True. It scavenges H2O2.

Question 27

How does Ropinrole work?

Answer 27

It is a DA agonist (D2). Smoothes fluctuations in response to L-DOPA treatment.

Question 28

When is Ropinirole used?

Answer 28

When the PD is mild.

Question 29

What are the toxic side effects from L-DOPA mainly due to?

Answer 29

The conversion of L-DOPA to DA in the periphery.

Question 30

What are the toxic side effects of L-DOPA?

Answer 30

Nausea/vomiting, orthostatic hypotension, dyskinesia, mental effects.

Question 31

How does vitamin B6 reduce L-DOPA activity?

Answer 31

It increases dopa decarboxylase activity.

Question 32

What is the effect of MAO inhibitors?

Answer 32

They increase DA activity. MAOb breaks down DA. MAOa breaks down NE and 5HT in the CNS.

Question 33

Why can a high protein meal affect PD treatment?

Answer 33

It can interfere with the absorption of L-DOPA from the gut.

Question 34

True or false: Benserazide inhibits decarboxylase activity in the periphery and has a longer duration of action that carbidopa.

Answer 34

True.

Question 35

How does Selegiline work?

Answer 35

Increases DA activity by inhibiting MAO-B activity.

Question 36

Benzotropine, Biperiden, Orphenadrine, Procyclidine, and Trihexyphenidyl are what kind of drugs?

Answer 36

Anti-cholinergic drugs. They decrease Ach activity.

Question 37

What is the mechanism of action of the anti-cholinergic drugs?

Answer 37

They are all Ach (muscarinic) blockers.

Question 38

What is MPTP?

Answer 38

A drug that causes PERMANENT PD. It is a neurotoxin to substantia nigra cells.

Question 39

What does a Thalamotomy procedure do?

Answer 39

Reduces tremor.

Question 40

What does a Pallidotomy do?

Answer 40

Lessens motor fluctuations permanently.

Question 41

What dose Pallidal stimulator do?

Answer 41

Lessens fluctuations. Can be regulated.