skip to main content

PD – COMT Inhibitor Dose Adjustment — SCE Neurology MCQ

Instant feedback + full explanation. One question, done properly.

ModerateMovement DisordersPD – COMT Inhibitor Dose AdjustmentSCE Neurology

A 60-year-old man with Parkinson's disease on co-careldopa 25/250 QDS has developed troublesome peak-dose chorea affecting the trunk and limbs. His neurologist wishes to add a COMT inhibitor but is concerned about worsening dyskinesia. What dose adjustment should accompany the addition of a COMT inhibitor?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — Reduce the individual levodopa dose by approximately 20–30% when adding a COMT inhibitor to reduce the risk of dyskinesia

When adding a COMT inhibitor (entacapone, opicapone, tolcapone) to levodopa, the levodopa dose should be reduced by approximately 20–30% to account for the increased levodopa bioavailability. Without this reduction, the higher levodopa exposure may worsen peak-dose dyskinesia, cause nausea, and increase the risk of hallucinations. This is a common clinical pitfall. A: Increasing would worsen dyskinesia. C: Dose adjustment is essential. D: Stopping levodopa is inappropriate. E: Doubling frequency would increase total exposure.

Reference: NICE NG71 Parkinson's Disease (2017); BNF