medicationPrescription only (US)FDA-approved for Parkinson's disease, drug-induced extrapyramidal reactions, and (historically) influenza A prophylaxis/treatment, though influenza use has fallen out of favor due to widespread viral resistanceUse for disorders of consciousness after traumatic brain injury is supported by randomized trial evidence but is not a formally FDA-approved indication
AmantadineBenefits, Dosage & Interactions
Also known as: Symmetrel, Gocovri
Amantadine is a prescription medication available orally, primarily known for its antiviral properties against influenza A and its role in treating Parkinson's disease and drug-induced extrapyramidal symptoms. It is also used to manage dyskinesia associated with levodopa therapy in Parkinson's disease patients.
How much Amantadine do people take?
The traumatic brain injury trials used 100 mg twice daily (200 mg per day total), titrated in some protocols to 150 mg twice daily. Route reported: Oral capsule, tablet, or syrup. Frequency reported: Twice daily in the cited traumatic brain injury trials. These are amounts documented in the cited studies and labels for Amantadine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
See the full reported protocol and its sourcesResearched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.
Evidence: Strong — 3 human randomized trials and regulatory approval on file.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
3 human randomized trials and regulatory approval on file.
Plasma half-life
15–17 h
Typical timing
in the morning
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
- Reported amounts
- The traumatic brain injury trials used 100 mg twice daily (200 mg per day total), titrated in some protocols to 150 mg twice daily[1][2][3]
Reported for Amantadine in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Amantadine entry is written from. Each number matches an inline marker above.
- [1]Placebo-controlled trial of amantadine for severe traumatic brain injuryGiacino JT, Whyte J, Bagiella E, et al. · The New England Journal of Medicine · 2012 · Peer-reviewed · PMID 22375973
- [2]A placebo-controlled randomized clinical trial of amantadine hydrochloride for evaluating the functional improvement of patients following severe acute traumatic brain injuryShimia M, et al. · Journal of Neurosurgical Sciences · 2023 · Peer-reviewed · PMID 34114429
- [3]Citicoline-Amantadine Trial in Traumatic Brain Injury: A Prospective Randomized StudyBadre DSEM, et al. · Journal of Neurotrauma · 2026 · Peer-reviewed · PMID 41027417
References & Evidence
Sources on this page that document Amantadine dosing, timing and safety.
- [1]U.S. National Library of Medicine View source
- [2]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Amantadine?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Amantadine is a prescription medication available orally, primarily known for its antiviral properties against influenza A and its role in treating Parkinson's disease and drug-induced extrapyramidal symptoms. It is also used to manage dyskinesia associated with levodopa therapy in Parkinson's disease patients. Originally approved as an antiviral, its use in influenza has declined due to widespread viral resistance.
Chemically, amantadine is a tricyclic amine. It acts on the central nervous system through multiple mechanisms, making it useful for neurological disorders. It is commonly studied for its effects on motor control and cognitive functions in Parkinson's disease.
Amatadine is typically taken by mouth, often once or twice daily depending on the specific formulation and condition being treated. It is a controlled medication, and its use requires a licensed clinician's prescription and oversight.
What does the research say about Amantadine?
Tap a section to expand.
Amantadine exerts its therapeutic effects through several distinct mechanisms of action in the central nervous system. Its primary neurological activities involve influencing dopaminergic and glutamatergic systems.
As a weak, non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, amantadine helps to modulate excessive glutamate activity. Overactivity of NMDA receptors is thought to contribute to excitotoxicity in various neurological conditions, including Parkinson's disease. By blocking these receptors, amantadine can help to reduce abnormal neuronal firing and improve motor control. Additionally, amantadine has been shown to enhance dopamine release from presynaptic nerve terminals and inhibit its reuptake, leading to increased dopamine levels in the synaptic cleft. This dopaminergic effect contributes to its efficacy in Parkinson's disease symptoms, addressing the characteristic deficiency of dopamine in the basal ganglia.
Beyond these main actions, amantadine also has anticholinergic properties, although these are generally weaker than those of other anticholinergic drugs. These multiple mechanisms of action allow amantadine to address various aspects of Parkinson's disease pathology and drug-induced movement disorders. Its antiviral mechanism against influenza A involves interfering with the uncoating of the virus by targeting the M2 protein, thereby preventing viral replication.
Source for this section: Sources for How does Amantadine work?: Jumps to this entry in the sources and references list at the end of the page.
* **Parkinson's Disease Symptoms:** According to the FDA prescribing information, amantadine is effective in treating early symptoms of Parkinson's disease, including tremor, rigidity, bradykinesia, and postural instability. It is also used as an adjunct to levodopa therapy.
* **Levodopa-Induced Dyskinesia:** Clinical studies reviewed by the European Medicines Agency (EMA) indicate that amantadine can significantly reduce the severity and duration of dyskinesia (involuntary movements) experienced by patients on long-term levodopa treatment for Parkinson's disease.
* **Drug-Induced Extrapyramidal Symptoms:** The Mayo Clinic patient monograph notes that amantadine is used to alleviate certain extrapyramidal symptoms (e.g., akathisia, dystonia, parkinsonism) caused by antipsychotic medications.
* **Influenza A Prophylaxis and Treatment:** Historically, amantadine was used for the prophylaxis and treatment of influenza A. However, MedlinePlus states that its use has largely diminished due to widespread viral resistance and the availability of newer, more effective antiviral agents.
The efficacy of amantadine for Parkinson's disease and levodopa-induced dyskinesia is supported by numerous clinical trials and meta-analyses. Regulatory agencies like the FDA and EMA have approved amantadine for these indications, reflecting established clinical evidence. For Parkinson's disease, particularly in its early stages or as an adjunct therapy, its benefits in improving motor symptoms are recognized.
Its role in levodopa-induced dyskinesia is particularly well-documented, with studies demonstrating a consistent reduction in dyskinesia severity. The Cochrane Database of Systematic Reviews has featured analyses on amantadine's role in Parkinson's disease, concluding that it can provide symptomatic relief. However, the evidence for its antiviral properties against influenza A, while historically significant, has been superseded by the emergence of widespread resistance, diminishing its practical utility in this area, as noted by the Centers for Disease Control and Prevention (CDC). Evidence for other off-label uses may be considered preliminary or less robust.
* **Common (≥1%):** Nausea, dizziness, insomnia, lightheadedness, anxiety, nervousness, abnormal dreams, dry mouth, constipation, edema (swelling of ankles), livedo reticularis (a purplish mottled discoloration of the skin).
* **Less Common:** Headache, fatigue, confusion, hallucinations (especially in older adults or those with cognitive impairment), orthostatic hypotension (a drop in blood pressure upon standing), blurred vision, loss of appetite, diarrhea. The FDA prescribing information notes these effects are generally dose-dependent.
* **Serious/Rare:** Neuroleptic Malignant Syndrome-like reactions upon abrupt withdrawal, severe psychiatric reactions (e.g., psychosis, suicidal ideation), seizures, congestive heart failure, corneal edema, angle-closure glaucoma, severe skin reactions, leukopenia. The FDA label highlights the potential for serious cardiovascular and psychiatric effects.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What are the side effects of Amantadine?: Jumps to this entry in the sources and references list at the end of the page.
Amantadine carries several important warnings, outlined in its FDA prescribing information. Patients with a history of congestive heart failure, peripheral edema, or renal impairment should use amantadine with caution, as it can exacerbate these conditions. Dosage adjustments are often necessary for individuals with kidney disease due to its primary renal excretion.
Patients with a history of seizures should also use amantadine cautiously, as it may lower the seizure threshold. Psychiatric adverse events, including hallucinations, confusion, and depression, can occur, particularly in elderly patients or those with existing psychiatric conditions. Rare cases of suicidal ideation and attempts have been reported. Abrupt discontinuation of amantadine, particularly in Parkinson's disease patients, can lead to the development of Neuroleptic Malignant Syndrome-like symptoms (e.g., fever, muscle rigidity, altered mental status, autonomic instability), which is a medical emergency. Therefore, withdrawal should be gradual under medical supervision. Individuals with untreated angle-closure glaucoma should avoid amantadine. Pregnant and breastfeeding individuals should discuss the potential risks and benefits with a clinician, as safety has not been definitively established.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for Who should avoid Amantadine?: Jumps to this entry in the sources and references list at the end of the page.
* Known hypersensitivity to amantadine or other components of the formulation.
* Severe renal impairment (creatinine clearance <10 mL/min) unless dose is significantly adjusted and closely monitored.
* Untreated angle-closure glaucoma.
* History of severe psychiatric disorders, including psychosis (relative contraindication, use with extreme caution).
* Use with certain anticholinergic agents or other drugs that prolong the QT interval (caution advised, not an absolute contraindication but increases risk).
Source for this section: Sources for When should Amantadine not be taken?: Jumps to this entry in the sources and references list at the end of the page.
* **Anticholinergic Agents (e.g., benztropine, trihexyphenidyl):** Increased risk of additive anticholinergic side effects such as dry mouth, blurred vision, constipation, and confusion.
* **Central Nervous System (CNS) Stimulants or Alcohol:** May increase the risk of CNS side effects like dizziness, confusion, and insomnia.
* **Thioridazine:** Concomitant use may increase amantadine plasma levels and the risk of adverse effects due to inhibition of amantadine metabolism.
* **Trimethoprim/Sulfamethoxazole:** Can reduce the renal clearance of amantadine, leading to increased plasma concentrations and potential toxicity.
* **Diuretics (e.g., hydrochlorothiazide, triamterene):** Certain diuretics can reduce the renal clearance of amantadine, increasing its levels in the body.
This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for What should you not mix with Amantadine?: Jumps to this entry in the sources and references list at the end of the page.
Amantadine is typically administered orally, with its timing often adjusted to optimize therapeutic effects and minimize side effects. When taken once daily, it is generally recommended in the morning to reduce the likelihood of insomnia, given its stimulating properties. If a twice-daily regimen is prescribed, the second dose is usually taken in the late afternoon to avoid nighttime sleep disturbances. Meals do not significantly affect amantadine absorption, so it can be taken with or without food, as tolerated. The half-life of amantadine is approximately 15 hours, which contributes to its once or twice-daily dosing schedule. However, in individuals with renal impairment, the half-life can be significantly extended, necessitating dosage adjustments and careful monitoring to prevent accumulation and toxicity. Due to its potential for CNS stimulation, taking it too close to bedtime may interfere with sleep.
Source for this section: Sources for When should you take Amantadine?: Jumps to this entry in the sources and references list at the end of the page.
Put it into practice
Reading about Amantadine is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.
What interacts with Amantadine?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any supplement + medication | Note | Category ruleConfidence: theoretical | Some supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Specific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist. |
| Any vitamin + medication | Note | Category ruleConfidence: theoretical | Certain vitamins interact with specific medications (e.g., vitamin K with blood thinners).Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Specific pairs are checked against a licensed source; confirm with your provider. |
| Lisinopril | Caution | Compound pairConfidence: theoretical | Amantadine can cause orthostatic hypotension; adding an ACE inhibitor may drop blood pressure further, especially on standing.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Watch for dizziness on standing. Rise slowly. Report lightheadedness or fainting to your clinician. |
| Amlodipine | Caution | Compound pairConfidence: theoretical | Amantadine plus a calcium-channel blocker can additively lower blood pressure and cause dizziness or ankle swelling.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Monitor BP at home. Rise slowly. Tell your clinician if you feel lightheaded. |
| Metoprolol | Caution | Compound pairConfidence: theoretical | Both drugs can lower heart rate and blood pressure. Combining raises risk of bradycardia, dizziness, and falls.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Check pulse and BP at home. Report a resting pulse under 55 or dizziness. |
| Caffeine | Caution | Compound pairConfidence: theoretical | Amantadine is CNS-stimulating; adding caffeine can worsen insomnia, jitteriness, anxiety, and elevated blood pressure.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Keep caffeine modest (≤200 mg/day) and avoid it after noon while on amantadine. |
| Bupropion | Caution | Compound pairConfidence: theoretical | Both lower seizure threshold and are dopaminergic. Combined use raises seizure and CNS-stimulation risk.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Use together only under a prescriber. Report tremor, agitation, or any seizure activity immediately. |
| Sertraline | Caution | Compound pairConfidence: theoretical | Rare reports of serotonin/NMS-like reactions when amantadine is combined with serotonergic drugs.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Watch for confusion, high fever, muscle rigidity, or shivering — seek urgent care if they appear. |
| St John's Wort | Caution | Compound pairConfidence: theoretical | St Johns wort is serotonergic and CNS-active; theoretical additive stimulation with amantadine.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Avoid combining unless cleared by your clinician. |
| Sildenafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors lower blood pressure; amantadine can add orthostatic hypotension.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Rise slowly; monitor BP. Report dizziness or fainting. |
| Tadalafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors lower blood pressure; amantadine can add orthostatic hypotension.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Rise slowly; monitor BP. Report dizziness or fainting. |
| Vardenafil | Caution | Compound pairConfidence: theoretical | PDE5 inhibitors lower blood pressure; amantadine can add orthostatic hypotension.Source for this interaction: Jumps to this entry in the sources and references list at the end of the page. | Rise slowly; monitor BP. Report dizziness or fainting. |
Frequently asked questions about Amantadine
According to patient experiences and clinical observations, some individuals may notice improvements in Parkinson's disease symptoms within a few days to a week of starting amantadine, while for others, it may take several weeks to observe maximum benefit. Individual responses can vary widely.
Long-term use of amantadine for Parkinson's disease is common. However, its effectiveness may wane over time for some individuals, a phenomenon known as "wearing off." The FDA prescribing information notes that long-term use requires ongoing monitoring for side effects, particularly psychiatric changes, cardiovascular issues, and kidney function.
Yes, amantadine can cause side effects such as dizziness, lightheadedness, blurred vision, and confusion, particularly at the beginning of treatment or after a dose increase. Patients should be cautioned about performing activities requiring mental alertness until they know how amantadine affects them, as advised by the manufacturer's patient information.
If you miss a dose of amantadine, take it as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and resume your regular dosing schedule. Do not double doses to catch up, as this can increase the risk of side effects, according to general medication guidelines.
As a medication, Amantadine can overlap with other supplements, prescription medicines, hormones and peptides. Because Amantadine is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. With a reported plasma half-life near 15 hours, separating doses can change the picture as much as removing one. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Amantadine with no sign-up.
Whether Amantadine fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Amantadine. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
With a plasma half-life near 15 hours, once-daily dosing is the usual pattern for Amantadine. It is typically taken in the morning. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
With a plasma half-life near 15 hours, a single missed dose of Amantadine usually has a smaller effect on overall exposure than an irregular pattern of missed doses does. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Amantadine the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
The traumatic brain injury trials used 100 mg twice daily (200 mg per day total), titrated in some protocols to 150 mg twice daily. Route reported: Oral capsule, tablet, or syrup. Frequency reported: Twice daily in the cited traumatic brain injury trials. These are amounts documented in the cited studies and labels for Amantadine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.
Which studies looked at Amantadine?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Amantadine in the treatment of Parkinson's disease and other movement disorders(opens PubMed in a new tab)Lancet Neurol · 2021 · PMID 34678171 · https://pubmed.ncbi.nlm.nih.gov/34678171/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- MedlinePlus(opens in a new tab)U.S. National Library of Medicine · medlineplus.gov/druginfo/meds/a682064.html
- PubChem CID 2130(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/2130
Verify at
Publisher search links for Amantadine. These are places to check the information — they are not citations, so they are not numbered.
- FDA-approved labeling (DailyMed)(publisher search, opens in a new tab)U.S. Food and Drug Administration · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- Mayo Clinic(publisher search, opens in a new tab)Mayo Clinic · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- CDC(publisher search, opens in a new tab)Centers for Disease Control and Prevention · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Amantadine?
Plain-text summary, safe to quote verbatim:
Amantadine is a prescription medication available orally, primarily known for its antiviral properties against influenza A and its role in treating Parkinson's disease and drug-induced extrapyramidal symptoms. It is also used to manage dyskinesia associated with levodopa therapy in Parkinson's disease patients.
Source: DoseRoutine — https://doseroutine.com/library/amantadine
Amantadine cheat sheet
DoseRoutine cheat sheet · Medication
Amantadine
Amantadine is a prescription medication available orally, primarily known for its antiviral properties against influenza A and its role in treating Parkinson's disease and drug-induced extrapyramidal symptoms. It is also used to manage dyskinesia associated with levodopa therapy in Parkinson's disease patients.
Evidence
Strong
3 human randomized trials and regulatory approval on file.
Studied range
The traumatic brain injury trials used 100 mg twice daily (200 mg per day total), titrated in some protocols to 150 mg twice daily
Route
Oral capsule, tablet, or syrup
Frequency studied
Twice daily in the cited traumatic brain injury trials
Half-life
15–17 h
Timing
in the morning
Prescription only (US)FDA-approved for Parkinson's disease, drug-induced extrapyramidal reactions, and (historically) influenza A prophylaxis/treatment, though influenza use has fallen out of favor due to widespread viral resistanceUse for disorders of consciousness after traumatic brain injury is supported by randomized trial evidence but is not a formally FDA-approved indication
Key references
- Placebo-controlled trial of amantadine for severe traumatic brain injury (2012)
- A placebo-controlled randomized clinical trial of amantadine hydrochloride for evaluating the functional improvement of patients following severe acute traumatic brain injury (2023)
- Citicoline-Amantadine Trial in Traumatic Brain Injury: A Prospective Randomized Study (2026)
Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/amantadine
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Amantadine — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/amantadine
What compounds are similar to Amantadine?
Others in the medication category or studied for the same goals.