A Parkinson's patient on levodopa-carbidopa for 6 years develops sudden random involuntary writhing movements of the limbs unrelated to dose timing. This phenomenon is termed:

• A Wearing-off effect (end-of-dose deterioration)
• B Peak-dose dyskinesias (choreiform or choreoathetoid movements at peak levodopa effect) ✓
• C On-off fluctuations
• D Freezing of gait

Explanation

Peak-dose dyskinesias are involuntary choreiform or choreoathetoid movements that occur when levodopa plasma levels (and thus striatal dopamine) are at their highest. They reflect dopaminergic receptor supersensitivity and pulsatile stimulation after prolonged therapy. Management includes reducing individual levodopa doses, adding amantadine (which reduces dyskinesias via NMDA receptor antagonism), or switching to continuous dopaminergic stimulation strategies.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.