Amantadine
Amantadine is an adamantane drug originally licensed as an antiviral and later widely used in Parkinson's disease and drug-induced extrapyramidal symptoms. It is a weak non-competitive NMDA receptor antagonist with additional dopaminergic actions, and is essentially non-psychoactive at therapeutic doses.
01 Overview
Amantadine has decades of clinical use. In Parkinson's disease it reduces dyskinesia and provides mild symptomatic benefit, attributed partly to NMDA antagonism and partly to enhanced dopamine release and reuptake inhibition. It is also used for fatigue in multiple sclerosis and to promote arousal after traumatic brain injury.
Because its NMDA affinity is low and its kinetics are moderate, it does not produce ketamine-like dissociation at normal doses. Overdose or high doses can cause confusion, hallucinations and, rarely, seizures. It is not a drug of recreational interest.
02 Mechanism
Weak uncompetitive NMDA receptor antagonist plus increased dopamine release and reduced reuptake; the mix underlies its anti-parkinsonian and antidyskinetic effects.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Parkinson's / dyskinesia | 100–300 mg/day | Oral | Usually 100 mg once or twice daily; extended-release forms differ. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Reduced dyskinesiaLowers levodopa-induced dyskinesia in Parkinson's disease. | clinically meaningful | Clinical | |
| Improved arousal / reduced fatigueUsed for post-TBI arousal and MS fatigue. | modest | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Confusion and hallucinationsVisual hallucinations, confusion and insomnia, especially in older patients or with renal impairment. | Moderate | Common in elderly/high dose | Clinical | |
| Livedo reticularis and ankle oedemaMottled skin discolouration and peripheral oedema on long-term use. | Mild | Common with chronic use | Clinical |