Medical Pharmacology Practice Questions: Anti-Parkinsonism Drugs

Concerning L-dopa pharmacokinetics, which one(s) of the following statements is/are correct?
1. L-dopa exhibits rapid small intestinal absorption.
2. The rate of small intestinal absorption of L-dopa depends on gastric content pH and gastric emptying rate.
3. Following an oral dose, peak plasma concentrations are usually noted between 1-2 hours.
4. A & B
5. B & C
6. A & C
7. A, B & C
Percentage of administered L-dopa that enters the brain unchanged is about:
1. 1-3%
2. 5-10%
3. 15-25%
4. About 50%
Administration of carbidopa, a peripheral dopa decarboxylase inhibitor, along with L-dopa can decrease daily L-dopa requirements by about 75%.
1. True
2. False
The optimum results of L-dopa treatment are noted in the latter stages of disease when L-dopa treatment is both most needed in most beneficial.
1. True
2. False
Choose the combination(s) of L-dopa, carbidopa and a catechol-o-methyltransferase (COMT) inhibitor formulation from the following:
1. Parcopa
2. Stalevo
3. Both
4. Neither
L-dopa-carbidopa administered by infusion into the duodenum or upper jejunum appears both safe and better compared to several oral combination treatments for patients exhibiting drug response fluctuations.
1. True
2. False
L-dopa is especially effective in relieving this clinical motor feature of parkinsonism:
1. Tremor
2. Bradykinesia
3. Equally effective in managing both features
Unless given with a peripheral decarboxylase inhibitor e.g. carbidopa, L-dopa may induce anorexia along with nausea and vomiting in a small percentage of patients.
1. True
2. False
Concerning levodopa in the brain: which one(s) of the following statements/statements is/are correct?
1. L-dopa is converted to dopamine
2. Dopamine is responsible for L-dopa therapeutic effectiveness
3. Both
4. Neither
Following dopamine release from dopaminergic terminals, which one(s) of the following activities may occur?
1. Reuptake of dopamine into the presynaptic, dopaminergic terminal
2. Dopamine metabolism by monoamine oxidase and catechol-o-methyltransferase (MAO & COMT)
3. Both
4. Neither