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# Amantadine

An old antiviral that helps Parkinson disease, mainly levodopa-induced dyskinesia. It is cleared by the kidney and can cause livedo reticularis.

Updated 2026-11-01

- Class: [Dopaminergic antiparkinson agents (levodopa and amantadine)](https://durgical.com/en/pharmacology/classes/dopaminergic-antiparkinson-agents/)
- Ion channel: NMDA glutamate receptor (channel pore)
- ATC code: N04BB01

⇅**NMDA glutamate receptor (channel pore)**Amantadine

ⓘ The figure shows memantine, a related adamantane drug, in the pore of the rat NMDA receptor; amantadine is a weaker NMDA receptor antagonist.

**Target in 3D:** NMDA glutamate receptor (channel pore). PDB structure 7SAD (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/7SAD) · Drag to rotate · pinch to zoom

## Mechanism of action

Amantadine is a weak, noncompetitive NMDA receptor antagonist and appears to increase dopamine release in the striatum. Blocking glutamate signalling in the basal ganglia reduces levodopa-induced dyskinesia. It also has anticholinergic-like effects. As an antiviral it blocked the M2 ion channel of influenza A, but circulating strains are now resistant.

- Amantadine blocks NMDA glutamate receptors
- Striatal dopamine release increases
- Overactive basal ganglia circuits calm down
- Dyskinesia and rigidity lessen

## Pharmacokinetics

**Absorption**
Well absorbed by mouth

**Elimination**
Mainly unchanged in the urine; accumulates in kidney failure

**Half-life**
About 17 hours in healthy adults (wide range), longer in older people and in kidney disease

## Indications

- Parkinson disease, and dyskinesia caused by levodopa [Parkinson disease →](https://durgical.com/en/conditions/parkinson-disease/)
- Drug-induced extrapyramidal reactions [Antipsychotic-induced movement disorders (dystonia, akathisia, parkinsonism, tardive dyskinesia) →](https://durgical.com/en/conditions/antipsychotic-induced-movement-disorders/)
- Influenza A (labelled), but no longer recommended because of widespread resistance [Influenza (flu) →](https://durgical.com/en/conditions/influenza/)

## Adverse effects

### Common

- Dizziness, insomnia, nausea
- Livedo reticularis (mottled skin, usually on the legs)
- Ankle and leg oedema
- Dry mouth, constipation, urinary retention
- Orthostatic hypotension

### Serious (rare, important)

- Hallucinations, confusion and psychosis, especially in older adults
- Suicidal thoughts and attempts
- Heart failure in susceptible patients
- Parkinsonian crisis or neuroleptic malignant syndrome-like state after sudden withdrawal
- Toxicity from accumulation in kidney failure; seizures

## Contraindications

- Hypersensitivity to amantadine
- Untreated angle-closure glaucoma (avoided); caution in kidney failure, heart failure, epilepsy and psychosis

## Key interactions

**Anticholinergic drugs**
More atropine-like effects and confusion

**Memantine and other NMDA antagonists**
Additive NMDA blockade; caution

**Live attenuated (intranasal) influenza vaccine**
Possible interference with the vaccine virus

**Alcohol and sedatives**
More dizziness, confusion and hypotension

## What is monitored

- Kidney function (creatinine clearance)
- Mental state, mood and suicidal thoughts
- Oedema, weight and signs of heart failure
- Skin of the legs (livedo reticularis)

## Administration and safety

- Not stopped abruptly in Parkinson disease; tapered
- Immediate-release and extended-release forms are different products
- Extended-release capsules are usually given at bedtime; other forms at the same times each day

## Nursing care

- Check kidney function, especially in older adults
- Watch for confusion, hallucinations and low mood
- Look at the legs for mottling and swelling
- Teach to rise slowly to avoid dizziness

## Pregnancy and breastfeeding

Human data are limited; use in pregnancy is a specialist decision.

## Memory aid

«AMANTAdine: A Mottled leg, A Nervous kidney»: livedo reticularis and renal clearance.

## Test yourself

Think of the answer, then tap the question to see it.

## For which complication of levodopa therapy is amantadine mainly used?

Levodopa-induced dyskinesia.

## Which skin finding is typical of amantadine?

Livedo reticularis, a mottled purplish pattern on the legs, often with ankle oedema.

## Why is amantadine no longer recommended for influenza?

Circulating influenza A viruses have high levels of resistance to the adamantanes.

## Why must the dose be reduced in kidney failure?

It is excreted mainly unchanged in the urine and accumulates, with toxicity that can be fatal.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/amantadine/)

## Related drugs

- [Levodopa + carbidopa](https://durgical.com/en/pharmacology/levodopa-carbidopa/)
- [Memantine](https://durgical.com/en/pharmacology/memantine/)

## Related conditions

- [Parkinson disease](https://durgical.com/en/conditions/parkinson-disease/)
- [Antipsychotic-induced movement disorders (dystonia, akathisia, parkinsonism, tardive dyskinesia)](https://durgical.com/en/conditions/antipsychotic-induced-movement-disorders/)
- [Influenza (flu)](https://durgical.com/en/conditions/influenza/)

[← Back to the class: Dopaminergic antiparkinson agents (levodopa and amantadine)](https://durgical.com/en/pharmacology/classes/dopaminergic-antiparkinson-agents/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - AMANTADINE HYDROCHLORIDE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=25af52ee-9b29-4c07-a383-62d4537b63e0) (DailyMed (U.S. National Library of Medicine), 2026); [Amantadine: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682064.html) (MedlinePlus (U.S. National Library of Medicine), 2025); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 21 (McGraw Hill, 2023); [Influenza Antiviral Medications: Summary for Clinicians](https://www.cdc.gov/flu/hcp/antivirals/summary-clinicians.html) (Centers for Disease Control and Prevention, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/amantadine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/amantadine/