parkinson drug

Question 1

what does levodopa do? MOA

Answer 1

It is a dopamine precursor, converted to dopamine in cns. After conversion, it acts as neurotransmitter dopamine which relieves PD symptoms.

Question 2

adverse effects of levodopa

Answer 2

Short term: n/v, postural hypotension

Long term: motor fluctuations, dyskinesia ( too much dopamine, no good regulation of it) 10% increase risk per year, it will stay even if u stop taking levodopa, usual episode is 40 mins:(

Question 3

indication of parkinson

Answer 3

Increase dopamine synthesis

Question 4

what is 2 in 1 preparation

Answer 4

-”2 in 1” preparation with peripheral decarboxylase inhibitors to help Levodopa to be converted to dopamine only in the brain, helps levodopa to cross the blood brain barrier easily. Eg. levodopa + carbidopa=sinemet. Or madopar.

Question 5

examples of Catechol-O-methyltransferase (COMT) inhibitors,

Answer 5

*Entacapone
Tolcapone

Question 6

indication of COMT, entacapone, tolcapone

Answer 6

inhibit dopamine breakdown

Question 7

MOA of entacapone, tolcapone

Answer 7

COM Blocks an enzyme that converts levodopa into an active form. By inhibiting COM, more levodopa is available to enter the brain
Increases duration of levodopa, beneficial in treating ‘wearing off” responses.

Question 8

side effects of COMT

Answer 8

-dyskinesia
-n/v
-urinary discolouration (orange brown/ rust coloured)
-visual hallucinations
-daytime drowsiness, sleep disturbances

*Tolcapone- liver dysfunction

Question 9

Are entacapone, tolcapone effective when taken alone?

Answer 9

no , -it is only effective when taken with levodopa

Question 10

indication of Selegiline

Answer 10

mild parkinson activity

Question 11

example of MAO-B inhibitors,

Answer 11

Selegiline

Question 12

MOA of selegiline, MAO B I

Answer 12

Inhibits enzyme monoamine oxidase B, which interferes with breakdown of dopamine. MAO-B I may delay the nigral brain cell degeneration.

Question 13

adverse effect of MAO- B I

Answer 13

-heartburn
-LOA
-nausea
-constipation
-dizziness
-anxiety, palpitation
-headache
-insomnia, nightmares
-confusion
-visual hallucination

Question 14

Can selegiline be taken alone?

Answer 14

*It is effective as a symptomatic monotherapy and may be used in early stages of parkinson’s disease

Question 15

example of Anticholinergic medication

Answer 15

trihexyphenidyl

Question 16

Adverse effects of trihexyphenidyl

Answer 16

-dry mouth
-constipation, urinary retention
-sedation, delirium, confusion, hallucination

Question 17

what is trihexyphenidyl effective for?

Answer 17

controlling tremors, sialorrhoea

Question 18

can anticholinergic trihexyphenidyl be used alone?

Answer 18

• may be used as symptomatic monotherapy or adjunct to levodopa to treat tremors and stiffness in PD.

Question 19

side effects of dopamine agonist

Answer 19

– similar to levodopa
– ‘ergot’ derivative - fibrosis
– pedal edema
– somnolence with ropinirole, pramipexole
– arrhythmia
– Pergolide - restrictive valvular heart disease

Question 20

Can dopamine agonists be taken alone?

Answer 20

Dopamine agonists are efficacious as
symptomatic monotherapy. Dopamine agonists
may also be used as an adjunct to levodopa in
the treatment of Parkinson’s disease

Question 21

should younger patients focus on taking levodopa or dopamine agonist?

Answer 21

In younger Parkinson’s disease patients,
therapy should commence first with dopamine
agonists rather than levodopa.