CH 21 Drugs for Parkinson's

Question 1

PD is a neurodegenerative disorder that produces characteristic motor symptoms: __(4)__

Answer 1

TRAP
tremor at rest, 
rigidity, 
akinesia (bradykinesia), and 
postural instability

Question 2

In addition to motor symptoms, PD can cause non-motor

symptoms, including __(5)__.

Answer 2

autonomic dysfunction, sleep disturbances, depression, psychosis, and dementia

Question 3

The primary pathology in PD is degeneration of neurons

in the substantia nigra that supply dopamine to the striatum. The result is an imbalance between ___.

Answer 3

dopamine and acetylcholine.

Question 4

Motor symptoms are treated primarily with drugs that
directly or indirectly activate ____. Drugs
that block cholinergic receptors can also be used.

Answer 4

dopamine receptors

Question 5

___ is the most effective treatment for motor symptoms.

Answer 5

Levodopa (combined with carbidopa)

Question 6

Levodopa relieves motor symptoms by ___ in surviving nerve terminals in the striatum.

Answer 6

undergoing conversion to dopamine

Question 7

The enzyme that converts levodopa to dopamine is called a ___.

Answer 7

decarboxylase

Question 8

Acute loss of response to levodopa occurs in two patterns:

Answer 8

gradual wearing off, which develops at the end of the dosing interval, and abrupt loss of effect (“on-off” phenomenon), which can occur at any time during the dosing interval.

Question 9

The principal adverse effects of levodopa are __(4)__.

Answer 9

nausea, dyskinesias, hypotension, and psychosis

Question 10

First-generation antipsychotic drugs block dopamine
receptors in the striatum, and can thereby negate the effects of levodopa. Two second-generation antipsychotics — (2) — do not block dopamine receptors in the striatum, and hence can be used safely to treat levodopa-induced psychosis.

Answer 10

clozapine and quetiapine

Question 11

Combining levodopa with a nonselective MAO inhibitor

can result in ___.

Answer 11

hypertensive crisis

Question 12

Because amino acids compete with levodopa for absorption from the intestine and for transport across the blood-brain barrier, ___ can reduce therapeutic effects.

Answer 12

high-protein meals

Question 13

__enhances the effects of levodopa by preventing decarboxylation of levodopa in the intestine and peripheral tissues. Because it cannot cross the blood-brain barrier, it does not prevent conversion of levodopa to dopamine in the brain.

Answer 13

Carbidopa

Question 14

___, an oral nonergot dopamine agonist, is a
first-line drug for motor symptoms. It can be used alone
in early PD and combined with levodopa in advanced PD.

Answer 14

Pramipexole

Question 15

___ relieve motor symptoms by causing direct activation of dopamine receptors in the striatum.

Answer 15

Pramipexole and other dopamine agonists

Question 16

The major adverse effects of pramipexole— __(4)__ —result from excessive activation of dopamine receptors.

Answer 16

nausea, dyskinesia, postural hypotension, and hallucinations

Question 17

___ is combined with levodopa to enhance levodopa’s effects. The drug inhibits metabolism of levodopa by COMT in the intestine and peripheral tissues, thereby making more levodopa available to the brain.

Answer 17

Entacapone (a COMT inhibitor)

Question 18

__(2)__ enhance responses to levodopa
by inhibiting MAO-B, the brain enzyme that inactivates
dopamine.

Answer 18

Selegiline and rasagiline

Question 19

Anticholinergic drugs relieve symptoms of PD by blocking ___.

Answer 19

cholinergic receptors in the striatum