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Dopaminergic / Antiviral (Adamantane Derivative)

Amantadine Hydrochloride

Brand names: Lysovir, Symmetrel

Amantadine hydrochloride is an oral agent used in Parkinson's disease, particularly to reduce levodopa-induced dyskinesia, and historically as an antiviral against influenza A.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It has dopaminergic actions (enhancing dopamine release and blocking reuptake) and NMDA-receptor antagonist activity, which underlies its benefit against dyskinesia.

Prescribing in practice

  • It can cause confusion, hallucinations and livedo reticularis, and should be withdrawn gradually because abrupt cessation may precipitate an acute confusional state or neuroleptic malignant syndrome-like reaction.
  • The dose should be reduced in renal impairment as it is largely renally excreted.
  • Avoid administration late in the day to limit insomnia and vivid dreams.

Monitoring

Monitor for neuropsychiatric effects and review renal function, especially in the elderly.

Counselling the patient

  • Do not stop the medicine suddenly; it should be reduced gradually.
  • Report confusion, hallucinations, mood change or ankle swelling.
  • A purplish mottling of the skin on the legs can occur and is usually reversible on stopping.

Evidence & guidelines

Amantadine is recognised by NICE for managing levodopa-induced dyskinesia in Parkinson's disease.

Reference: NICE NG71 (Parkinson's disease in adults, 2017 updated 2022); Parkinson's UK drug factsheet on amantadine; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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