Question

Which one of the following statements is TRUE regarding drugs used in parkinsonism?

• A. Amantadine causes ankle oedema
• B. Levodopa is particularly effective in reducing tremor
• C. Amantadine is more effective than levodopa
• D. Antimuscarinics are effective in drug-induced parkinsonism

Hint:

Amantadine's classic side effects are ankle oedema and livedo reticularis. Levodopa helps tremor least of the cardinal signs, and only central antimuscarinics work in drug-induced parkinsonism.

Answer 1

The Correct Option is A

This question checks specific, well known facts about the drugs used for Parkinson's disease. Let's go through each option.

1. Amantadine causes ankle oedema: correct. Amantadine is well known to cause fluid retention in the lower legs, seen as ankle swelling, along with a mottled skin rash called livedo reticularis.
2. Levodopa is particularly effective in reducing tremor: incorrect. Levodopa works best on slowness of movement and stiffness. Tremor is usually the slowest symptom to respond and can even persist despite good control of the other signs.
3. Amantadine is more effective than levodopa: incorrect. Amantadine acts faster than levodopa but is far weaker. Levodopa is still the most powerful drug available for parkinsonism.
4. Antimuscarinics are effective in drug-induced parkinsonism: incorrect as a blanket statement. Only antimuscarinics that cross into the brain, the central ones like trihexyphenidyl, help here, since drug-induced parkinsonism comes from a brain level imbalance between dopamine and acetylcholine.

Only the first statement holds up without any qualification, so amantadine causing ankle oedema is the correct answer.

Let's summarize:

• Amantadine: fast acting but weak, causes ankle oedema and livedo reticularis.
• Levodopa: strongest drug, helps rigidity and bradykinesia more than tremor.
• Only central antimuscarinics help in drug-induced parkinsonism.

The correct statement is that amantadine causes ankle oedema.