Amantadine
Trade names
- SYMMETREL
Actions
Incompletely understood. Known mechanisms of action include:
- Weak, non-competitive NMDA receptor antagonism.
- Stimulation of dopamine release.
- Inhibition of dopamine reuptake.
- Anticholinergic action.
Route of Administration
Oral
Bioavailability
86–90%
Plasma protein binding
67%
Half-life
10-31 hours
Metabolism
Not significantly metabolized
Elimination
Renal
Important side-effects
Suicidal ideation and behavior.
May lower seizure threshold.
May worsen congestive heart failure.
May worsen or precipitate delusions, hallucinations or psychosis.
May worsen memory problems, confusion and delirium, especially in the elderly.
Should not be given to patients with untreated closed angle glaucoma.
Recommended dose
100 mg twice a day when used alone.
Onset of action is usually within 48 hours.
Renal impairment
| Creatinine clearance (ml/min/1.73 m2) | Dose and frequency |
|---|---|
| 30-50 | 200 mg 1st day, 100 mg/day thereafter |
| 15 to 29 | 200 mg 1st day, 100 mg on alternate days |
<15 | 200 mg every 7 days |
| On dialysis | 200 mg every 7 days |
Hepatic impairment
No dose adjustment is necessary.