Reference — Neurology
Antiparkinsonian Medications Reference
Every Parkinson’s drug is trying to do one thing — raise dopamine’s effect or rebalance it against acetylcholine. Here are the classes, what they do, and the side effects and timing rules that nursing care turns on.
Educational use only. Regimens are individualized and precisely timed; give doses on the patient’s schedule, never stop abruptly, and follow provider orders for titration and interactions. This material supports nursing education and exam review. It is not medical advice and is not a substitute for clinical judgment, institutional policy, or medical direction. Always follow facility protocols and current provider orders.
Drug Classes
| Class | Examples | Mechanism | Nursing notes |
|---|---|---|---|
| Dopamine precursor | Carbidopa-levodopa | Levodopa → dopamine in the CNS; carbidopa blocks peripheral breakdown | Most effective; on-off phenomenon and dyskinesias over time; protein may compete with absorption; give on time |
| Dopamine agonists | Pramipexole, ropinirole, rotigotine | Directly stimulate dopamine receptors | Watch for somnolence/sleep attacks, hallucinations, and impulse-control disorders (gambling, shopping) |
| MAO-B inhibitors | Selegiline, rasagiline | Block dopamine breakdown by monoamine oxidase-B | Tyramine/serotonin-syndrome caution; avoid certain drugs/foods; can extend levodopa effect |
| COMT inhibitors | Entacapone, tolcapone | Block peripheral levodopa breakdown to prolong its effect | Given WITH levodopa; harmless urine discoloration; tolcapone needs liver monitoring |
| Anticholinergics | Benztropine, trihexyphenidyl | Rebalance acetylcholine vs dopamine; help tremor | Anticholinergic effects — confusion (esp. elderly), dry mouth, urinary retention, constipation |
| Other | Amantadine | Increases dopamine release; antiviral origin | Helps dyskinesias; watch for livedo reticularis, confusion, ankle edema |
Cross-Cutting Rules
Timing is treatment: these are often time-critical medications — a late dose can leave a patient frozen and unsafe. Give on the home schedule, including during procedures and transfers.
Never stop abruptly: sudden withdrawal of dopaminergic therapy can cause an akinetic crisis and a neuroleptic-malignant-like syndrome.
Avoid dopamine blockers: metoclopramide and typical antipsychotics worsen Parkinson’s — flag them.
On-off & dyskinesia: as the levodopa window narrows over years, expect abrupt mobility swings and involuntary movements; report changes for regimen adjustment.
NCLEX Pearls
- ✦Carbidopa-levodopa is the most effective drug; carbidopa lets more levodopa reach the brain and cuts side effects.
- ✦Give doses ON TIME and never stop abruptly — abrupt withdrawal risks akinetic crisis.
- ✦Dopamine agonists can cause sleep attacks and impulse-control disorders (gambling, shopping) — ask about these.
- ✦Avoid dopamine-blocking drugs (metoclopramide, typical antipsychotics).
- ✦On-off phenomenon and dyskinesias signal the levodopa window is narrowing — report for adjustment.
Related Resources
Standards & sources
Fact-checked Jun 21, 2026This page is written to align with American Heart Association / American Stroke Association (AHA/ASA) · American Association of Neuroscience Nurses (AANN). It is an educational summary, not a citation of any single document — always verify specific doses, values, and protocols against current guidelines and your facility policy. How we source content →