Parkinson's Drugs

Question 1

Levodopa

Answer 1

Is a Prodrug form of dopamine. Its conversion to dopamine is facilitated by L-aromatic amino acid decarboxylase. It is effective orally. L-Dopa is able to cross the BBB. It is able to be converted to dopamine in the periphery as well which leads to nausea. Consider adding carbidopa.

Question 2

Carbidopa

Answer 2

Inhibits L-aromatic amino acid decarboxylase. Carbidopa does not cross the BBB so it only inhibits the enzyme in the periphery leading to increased dopamine in the CNS.

Question 3

Sinemet

Answer 3

Is a combination of carbidopa and Levodopa. It is currently the standard treatment for parkinsons

Question 4

Entacapone

Answer 4

Inhibits COMT leading to decreased peripherial metabolism of L-DOPA into 3-methoxy-4-hydroxy-L-phenylalanine by catechol-o-methyltranferase (COMT). This is the opposite of turning into dopamine. It can be given with Sinermet and is used to alleviate the on/off times.

Question 5

Selegiline

Answer 5

Is a MAO (B) Inhibitor. It is useful for parkinson’s treatment and is effectively early as amonotherapy or combined with L-DOPA. It also smooths on-off fluctuations.

Question 6

Pramipexole

Answer 6

Dopamine D2 receptor agonist.

Question 7

Trihexyphenidyl

Answer 7

is a muscarinic antagonist. ACH is used as a neurotransmitter by a small but improtant subgroup of striatal interneurons.

Question 8

Amantadine

Answer 8

Antiviral drug which also has a temporary effect for parkinson’s. Its mechanism is unclear.