Which medication is commonly used as first-line symptomatic treatment for Parkinson disease?

• A. Levodopa-carbidopa
• B. Amantadine
• C. Selegiline
• D. Ropinirole

Answer: (A)

Parkinson disease symptoms come from a loss of dopamine in the brain, so the most effective way to improve motor function is to restore dopamine activity in the striatum. Levodopa is a dopamine precursor that crosses the blood–brain barrier and is then converted to dopamine in the brain, directly addressing the deficit. When combined with carbidopa, a peripheral decarboxylase inhibitor, more levodopa reaches the brain and peripheral side effects (like nausea and low blood pressure) are reduced. This combination provides the strongest and most reliable improvement in bradykinesia, rigidity, and overall motor function compared with other options.

Other drugs can help, but they are typically used for different reasons or situations: amantadine offers modest benefit and can help with dyskinesias; selegiline (an MAO-B inhibitor) and ropinirole (a dopamine agonist) can be useful, especially early in disease or to delay reliance on levodopa in younger patients, but they do not match levodopa-carbidopa for overall symptom control.