This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'Anti-Parkinsonism drug that is a selective COMT inhibitor \nSelect and explain. \nA. Entacapone, B. Ropinirole, C. Pergolide, D. Pramipexole', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Inhibitors of COMT increase the elimination half-life of levodopa and enhance its brain availability. Combining levodopa with a COMT inhibitor reduces "off" time and prolongs "on" time in fluctuating patients while enhancing motor scores. Two COMT inhibitors have been approved, tolcapone and entacapone. Reference: Harrison\'s Principles of Internal Medicine; 19th edition; Chapter 449; Parkinson\'s Disease and Other Movement Disorders', 'role': 'assistant'}]