CNS Drugs · NEET PG Preparation Pharmacology
A 65-year-old man with Parkinson disease is managed with levodopa/carbidopa. To reduce peripheral adverse effects such as nausea and orthostatic hypo…
Practice question from CNS Drugs (NEET PG Preparation Pharmacology), with the correct answer and a step-by-step solution.
easy · MCQ · Q-2C4120
A 65-year-old man with Parkinson disease is managed with levodopa/carbidopa. To reduce peripheral adverse effects such as nausea and orthostatic hypotension while preventing peripheral conversion of levodopa to dopamine, carbidopa is co-administered. Which enzyme does carbidopa specifically inhibit?
- A.Monoamine oxidase B
- B.Catechol-O-methyltransferase
- C.Aromatic L-amino acid decarboxylaseCorrect answer
- D.Tyrosine hydroxylase
Solution
Carbidopa is a peripheral inhibitor of aromatic L-amino acid decarboxylase (dopa decarboxylase). Because it does not cross the blood-brain barrier effectively, it prevents the peripheral breakdown of levodopa without interfering with its central conversion in the brain.
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