PARKINSONISM

Question 1

What are the four signs of Parkinsons?

Answer 1

Rigidity of skeletal muscles
Akinesia
Flat facies
Tremor

(RAFT)

Question 2

Give the two types of Parkinsons

Answer 2

Naturally occurring - unknown cause
Drug induced - usually reversible.

Question 3

Give three types of drugs that cause drug induced parkinsonism

Answer 3

1) Butyrophenone and phenothiazine
2)Reserpine at high doses
3)MPTP a byproduct of attempted synthesis of meperidine that causes irreversible Parkinson’s

Question 4

Give three ways in which Parkinsons is treated.

Answer 4

Increasing dopamine activity in brain
Decrease muscarinic cholinergic activity.
Both

Question 5

Give the drugs that enhance dopaminergic activity in the brain.

Answer 5

1) Dopamine precursor such as levodopa
2) Dopamine agonists such as bromocriptine
3)MAO inhibitors such as selegiline
4) COMT inhibitors such as entacapone
5) Amantadine

(LABSE)

Question 6

Give the muscarinic antagonist

Answer 6

benztropine

Question 7

Why is levodopa given instead of dopamine

Answer 7

Levodopa is a precursor of dopamine that can readily cross the BBB unlike dopamine then converted to dopamine via dopa carboxylase /L-amino decarboxylase

Question 8

Since dopa decarboxylase is found in many peripheral tissues it can cause adverse effects such as hypotension . To prevent this levodopa is administered with

Answer 8

carbidopa - an inhibitor of dopa decarboxylase in peripheral tissues but does not cross BBB

Question 9

Although levodopa shows improvement in the first few years and slows mortality , it is limited due to three main things

Answer 9

Cannot cure parkinsonism.
The responsiveness fluctuates.
Patients experience decline in 3-5yrs due to progression of disease.

Question 10

Levodopa experiences a phenomena known as

Answer 10

on-ff

Question 11

The A/E of Levodopa may be grouped into Peripheral and CNS . Give examples of each

Answer 11

Peripheral
1) GIT problems - tolerance to the emetic action occurs after several months
2) Postural hypotension
3) Mydriasis
4) Blood dyscrasias
5) Positive Coombs test
6) Saliva and urine a brownish colour
CNS
1) Dyskinesia and psychosis that show overactivity of dopamine neurons.
2)Mood changes such as anxiety and depression

Question 12

Levodopa has a short half life of

Answer 12

1-2 hrs

Question 13

Give the relationship between levodopa and meals

Answer 13

Should be taken on an empty stomach

Question 14

Give three main drug interactions with levodopa

Answer 14

1) Vb6 that causes its breakdown thus reducing effectiveness
2) MAOIs that can cause a hypertensive crisis
3) Antipsychotics that inhibit dopamine neurons thus worsening of the Parkinsons

Question 15

Give the C/I of Levodopa

Answer 15

Patients with a history of psychosis

Question 16

Wich two groups of patients should be monitored closely when taking Levodopa

Answer 16

Antipsychotic patients
Cardiac patients due to development of arrhythmias

Question 17

The Dopamine receptor agonists can be grouped into

Answer 17

1) Ergot derivatives - bromocriptine
2) Non ergot derivatives - ropinirole , pramipexole , rotigotine and apomorphine

Question 18

Dopamine receptor agonists are preferred to Levodopa as

Answer 18

They have a longer duration of action
They are effective in patients who experience flactuations with levodopa

Question 19

Between Levodopa and Bromocriptine , which is more common in

1) Dyskinesia
2) Hallucination , confusion , postural hypotension , nausea

Answer 19

1) Levodopa
2) Bromocriptine

Question 20

Bromocriptine acts on which dopamine receptor

Answer 20

It is a partial agonist at D2 receptors in the brain

Question 21

Give three clinical uses of bromocriptine

Answer 21

1) As an individual drug
2) In combination with levodopa
3) Patients unable to tolerate levodopa

Question 22

Give three types of patients that need to be monitored with use of Bromocriptine

Answer 22

In psychotic patients
History of vascular disease and MI
Can cause pulmonary and retroperitoneal fibrosis

Question 23

Bromocriptine as an ergot derivative has 2 unique A/E

Answer 23

Erythromelalgia
Pulmonary infiltrates - pulmonary and retroperitoneal fibrosis

Question 24

Give the classification of the non ergot Dopamine receptor agonists

Answer 24

Oral - Paramipexole and Ropinirole
Transdermal - Rotigotine
Injectable - Apormophine

Question 25

Unlike bromocriptine , the non ergot Dopamine receptor agonists di nit cause

Answer 25

Pulmonary and retroperitoneal fibrosis
Vascular disease

Question 26

Pramipexole has a high affinity for which dopamine receptor

Answer 26

D3

Question 27

Pramipexole is termed as neuroprotective due to

Answer 27

Neuroprotective as it is a scavenger for hydrogen peroxide

Question 28

Pramipexole is excreted renally , which drug may inhibit tubular secretin and increase its plasma kevels.

Answer 28

Cimetidine

Question 29

Give the C/I of pramipexole

Answer 29

PUD , MI and psychotic illness

Question 30

Ropinirole has an affinity for which dopamine receptor

Answer 30

D2

Question 31

Ropinirole is metabolised by

Answer 31

CYP1A2

Question 32

Apomorphine is mainly used for and what is the duration and onset of action

Answer 32

Temporary relief during off period of akinesia and has an onset of 10 min and a duration of 1-2hrs

Question 33

Give an A/E of Apomorphine

Answer 33

Severe nausea , antiemetics given 3 days befre treatment

Question 34

Give two examples of MAOIs

Answer 34

Selegiline
Rasagiline

Question 35

Selegiline undergoes hepatic metabolism to give

Answer 35

Desmethylselegiline and amphetamine

Question 36

Give the DDI of MAOIs

Answer 36

1) When given with Mepiridine it can cause mortality , agitation and delirium
2) Selegiline when combined with ssris can cause serotonin syndrome

Question 37

Give examples of COMT inhibitors

Answer 37

Entacapone and Tolacapone

Question 38

Give the MOA of COMT

Answer 38

COMT is an enzyme found in the brain and peripheral tissues that coverts L-dopa to 3-O-methyldopa (3-OMD)

Question 39

COMTIs increase on time

Answer 39

true

Question 40

What should be monitored with Tolacapone

Answer 40

LFTS