Dopamine Agonist / NMDA Antagonist (Anti-Parkinsonian) Pregnancy: Avoid — teratogenic in animal studies

Amantadine

Brand names: Lysovir

Adult dose

Dose: Parkinson's disease: 100 mg OD (morning) × 1 week, then 100 mg BD. Antiviral (influenza A, historical): 100 mg OD × 5 days.

Route: Oral

Frequency: OD–BD

Max: 400 mg/day

For Parkinson's disease — especially useful for drug-induced dyskinesias (levodopa). Also has antiviral (influenza A) activity. Last dose no later than 4pm to avoid insomnia.

Paediatric dose

Route: N/A

Frequency: N/A

Max: Not licensed for Parkinson's in children

Not routinely used in children for neurological indications

Dose adjustments

Renal

Significant reduction required in renal impairment (renally excreted): eGFR 30–50: 100 mg OD; eGFR 15–30: 100 mg every other day; eGFR <15: 200 mg once per week

Hepatic

No dose adjustment required

Clinical pearls

Livedo reticularis: characteristic harmless skin discolouration — reassure patient
Dyskinesia treatment: amantadine reduces levodopa-induced dyskinesias by NMDA antagonism — useful add-on in advanced Parkinson's
Timing of last dose: no later than 4pm — significant insomnia if taken later
Tolerance may develop after 6–8 weeks — temporary cessation may restore response

Contraindications

Severe renal impairment (dose according to eGFR)
Epilepsy (lowers seizure threshold)

Side effects

Insomnia (avoid doses after 4pm)
Dizziness
Livedo reticularis (mottled skin — reversible)
Ankle oedema
Hallucinations
Confusion
Nausea

Interactions

Anticholinergics — additive CNS effects
Thiazide diuretics — reduced renal amantadine clearance (increased toxicity)
Alcohol — increased CNS side effects

Monitoring

Renal function (dose adjustment)
Neurological status
Signs of livedo reticularis
Ankle oedema
Sleep quality

Reference: BNFc; BNF; NICE NG71 Parkinson's Disease. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways