Neurology/Levodopa

Levodopa (co-careldopa / co-beneldopa)

also: L-dopa · carbidopa · benserazide · Sinemet · Madopar

Overview

The most effective Parkinson's drug — but motor complications (wearing-off, dyskinesia) develop over years, and it must never be stopped abruptly.

Mechanism

Levodopa is a dopamine precursor that crosses the blood–brain barrier (dopamine itself cannot). It is combined with a peripheral DOPA-decarboxylase inhibitor (carbidopa/benserazide) to block peripheral conversion → less nausea/hypotension and more reaches the brain.

Indications

Idiopathic Parkinson's disease (esp. when motor symptoms impair quality of life)

The agents

Co-careldopalevodopa + carbidopa

oral, on time

Sinemet.

Co-beneldopalevodopa + benserazide

oral

Madopar.

Adverse effects

Motor complications: wearing-off, on–off, peak-dose dyskinesiaclassic

Develop over ~5 years — the reason to delay/limit dose in younger patients.

Nausea, postural hypotensioncommon

Use domperidone (not metoclopramide) for nausea.

Hallucinations / confusion (esp. elderly)common

Cautions & contraindications

Abrupt withdrawalall

Acute akinesia / neuroleptic-malignant-like crisis — give via NG or switch to a rotigotine patch if NBM.

Dopamine-antagonist antiemetics (metoclopramide/prochlorperazine)all

Worsen PD — use domperidone/cyclizine.

Interactions

Absorption ↓ by protein meals; MAO-B inhibitors potentiate

Monitoring & kinetics

Motor response/fluctuations; BP (postural)

Oral — strict timing (give on time in hospital). Rotigotine patch if nil-by-mouth.

Choosing it

true

Source: NICE NG71 — Parkinson's · BNF — Levodopa