Amantadine Dosage

Medically reviewed by Drugs.com. Last updated on Aug 3, 2023.

Usual Adult Dose for Influenza Prophylaxis

Initial dose: 200 mg/day orally in 1 or 2 divided doses

Comments:

• Twice-daily dosing may minimize CNS side effects; dose reduction to 100 mg/day may be necessary if higher dose is not tolerated.
• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Uses: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Usual Adult Dose for Influenza A

Initial dose: 200 mg/day orally in 1 or 2 divided doses

Comments:

• Twice-daily dosing may minimize CNS side effects; dose reduction to 100 mg/day may be necessary if higher dose is not tolerated.
• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Uses: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Usual Adult Dose for Parkinson's Disease

Immediate-release formulations: 100 mg orally twice a day

• May increase up to 400 mg/day in divided doses as needed under close supervision

Extended-release tablets: Initial dose: 129 mg orally once a day in the morning

• May increase in weekly intervals up to a maximum dose of 322 mg/day

Extended-release capsules: Initial dose: 137 mg orally once a day at bedtime

• May increase after 1 week to recommended dose of 274 mg orally once a day at bedtime

Comments:

• Extended-release capsules and tablets are not interchangeable with each other or with other amantadine formulations; see administration advise for additional administration information.
• For patients experiencing a falling-off effect after initial benefit with the immediate-release formulations, it may be beneficial to consider increasing the dose to 300 mg/day or temporarily interrupting therapy followed by re-initiation.
• This drug may be added to levodopa based therapy, with or without concomitant dopaminergic medications; adding this drug to optimal well-tolerated doses of levodopa may smooth out fluctuations that can occur with levodopa alone; patients reducing levodopa dose due to side effects may regain lost benefit with the addition of amantadine.

Uses: For the treatment of dyskinesia in patients with Parkinson's disease; the extended-release capsules are additionally indicated as adjunctive treatment to levodopa/carbidopa in patients with Parkinson's disease experiencing "off" episodes.

Usual Adult Dose for Extrapyramidal Reaction

Immediate-release formulations: Initial dose: 100 mg orally twice a day

• Titration to 300 mg daily in divided doses may be beneficial in some patients

Extended-release tablets: Initial dose: 129 mg orally once a day in the morning

• May increase in weekly intervals up to a maximum dose of 322 mg/day

Comments:

• The extended-release capsules are not indicated for the treatment of drug-induced extrapyramidal reactions; extended-release tablets are not interchangeable with other amantadine formulations; see administration advise for additional administration information.

Use: For treatment of drug-induced extrapyramidal reactions.

Usual Geriatric Dose for Influenza Prophylaxis

65 years or older: 100 mg orally per day

Comments:

• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Uses: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Usual Geriatric Dose for Influenza A

65 years or older: 100 mg orally per day

Comments:

• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Uses: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Usual Pediatric Dose for Influenza Prophylaxis

1 to 9 years: 4.4 to 8.8 mg/kg/ day orally
Maximum dose: 150 mg/day

9 to 12 years: 100 mg orally twice a day

Advisory Committee on Immunization Practices (ACIP) and American Academy of Pediatrics (AAP) recommendations (to reduce risk for toxicity):
1 to 9 years: 5 mg/kg orally per day in 2 divided doses; not to exceed 150 mg/day
10 years or older, less than 40 kg: 5 mg/kg orally per day
10 years or older, 40 kg or more: 100 mg orally twice a day

Alternative prophylactic dose for children weighing more than 20 kg: 100 mg per day

Comments:

• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are currently not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Use: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Usual Pediatric Dose for Influenza A

1 to 9 years: 4.4 to 8.8 mg/kg/ day orally
Maximum dose: 150 mg/day

9 to 12 years: 100 mg orally twice a day

Advisory Committee on Immunization Practices (ACIP) and American Academy of Pediatrics (AAP) recommendations (to reduce risk for toxicity):
1 to 9 years: 5 mg/kg orally per day in 2 divided doses; not to exceed 150 mg/day
10 years or older, less than 40 kg: 5 mg/kg orally per day
10 years or older, 40 kg or more: 100 mg orally twice a day

Alternative prophylactic dose for children weighing more than 20 kg: 100 mg per day

Comments:

• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are currently not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• Influenza viruses change from season to season and can even change within the course of one flu season; updated guidance may be obtained at www.cdc.gov/flu

Use: For the prophylaxis and treatment of signs and symptoms of infection caused by various strains of influenza A virus.

Renal Dose Adjustments

Immediate-release:

• Mild renal impairment (CrCl greater than 50 mL/min/1.73 m2): No adjustment recommended
• Moderate renal impairment (CrCl 30 to 50 mL/min/1.73 m2): 200 mg orally on day 1 followed by 100 mg orally once a day thereafter
• Severe renal impairment (CrCl 15 to 29 mL/min/1.73 m2): 200 mg orally on day 1 followed by 100 mg orally every other day thereafter
• ESRD (CrCl less than 15 mL/min/1.73 m2): 200 mg orally every 7 days

Extended-release capsules:

• Mild renal impairment (CrCl 60 to 89 mL/min/1.73 m2): No adjustment recommended
• Moderate renal impairment (CrCl 30 to 59 mL/min/1.73 m2): Initial dose: 68.5 mg orally once a day at bedtime; increase after 1 week to maximum dose of 137 mg/day if needed
• Severe renal impairment (CrCl 15 to 29 mL/min/1.73 m2): 68.5 mg orally once a day at bedtime
• ESRD (CrCl less than 15 mL/min/1.73 m2): Contraindicated

Extended-release tablets:

• Mild renal impairment (eGFR 60 to 89 mL/min/1.73 m2): No adjustment recommended
• Moderate renal impairment (eGFR 30 to 59 mL/min/1.73 m2): Reduce frequency of dosing to 1 dose every 48 hours; increase minimum titration interval to every 3 weeks
• Severe renal impairment (eGFR 15 to 29 mL/min/1.73 m2): Decrease frequency of dosing to 1 dose every 96 hours; increase minimum titration interval to every 4 weeks
• ESRD (eGFR less than 15 mL/min/1.73 m2): Contraindicated

Liver Dose Adjustments

Use with caution

Dose Adjustments

For Patients with Serious Associated Medical Illness or receiving High Doses of Other Anti-Parkinson Drugs:

• Initial dose: 100 mg orally once a day; may increase to 100 mg twice a day after 1 week as needed

Elderly Patients: No dose adjustment is necessary based on age, however, because elderly patients are more likely to have decreased renal function, use caution in dose selection; it may be useful to monitor renal function

Dose reductions may be necessary in patients with congestive heart failure, peripheral edema, or orthostatic hypotension

Therapy Discontinuation:

• Avoid sudden discontinuation in patients receiving this drug for more than a few weeks (e.g., 4 weeks)
• Gradually reduce higher dose to lowest dose, then discontinue after 1 to 2 weeks

Precautions

CONTRAINDICATIONS:

• Known hypersensitivity to the active substance or any product ingredients
• ESRD (CrCl less than 15 mL/min/1.73 m2 [ER capsules and ER tablets])

Safety and efficacy have not been established in patients younger than 1 year.
Safety and efficacy of the extended-release formulations have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.

Dialysis

Immediate-release:

• Hemodialysis: 200 mg orally every 7 days
• Peritoneal dialysis: Data not available

Extended-release: Data not available

Other Comments

Administration advice:
Immediate-release: Take orally once or twice a day

Extended-release capsules: Take orally once a day at bedtime with or without food

• Swallow whole; do not crush, chew, or divide capsules
• If unable to swallow whole, may open the capsule and sprinkle the entire contents on a small amount of soft food and swallow immediately without chewing
• Concomitant use with alcohol is not recommended as it may result in dose-dumping

Extended-release tablets: Take orally once a day in the morning with or without food

• Swallow whole; do not crush, chew, or divide capsules
• Ghost tablet may appear in stool

Missed dose (extended-release tablet or capsule): If a dose is missed, the next dose should be taken as scheduled

Storage requirements:

• Protect from moisture
• If extended-release capsule is opened, contents should be ingested promptly, do not store mixture for future use

General:

• Due to antiviral resistance, adamantanes which include amantadine and rimantadine, are not recommended by the Centers for Disease Control and Prevention (CDC) for treating and preventing influenza virus illness in the United States.
• This drug is indicated in the treatment of Parkinson's disease; it is considered less effective than levodopa, but used in combination may smooth out fluctuations which may occur with levodopa alone.
• Extended-release tablets and extended-release capsules have different release kinetics; they are not interchangeable.

Monitoring:

• Monitor renal function as clinically indicated
• Monitor for orthostatic hypotension and dizziness
• Monitor for depression including suicidal ideation or behavior
• Monitor for hallucinations, especially after initiation and with any dose increases or decreases
• Monitor/ask about intense urges to gamble, binge eat, sex, etc; be specific as patients may not recognize these as abnormal

Patient advice:

• Patients should be instructed to read the US FDA-approved patient labeling (Patient Information).
• Patients should be instructed not to abruptly discontinue therapy.
• Patients should be advised that there have been reports of patients falling asleep while engaged in activities of daily living and this may affect their ability to drive or operate machinery; they should tell their healthcare provider right away if this happens to them.
• Patients should be instructed to report any new or unusual behaviors including hallucinations, thoughts of suicide, or intense urges.
• Patients should be aware that orthostatic hypotension and dizziness may occur and they should be cautioned about standing rapidly.
• Patients should be counseled about alcohol use; concomitant use increases the potential for CNS toxicity; concomitant use with extended-release capsules may result in dose-dumping.

Frequently asked questions

• What is the difference between Osmolex ER and Gocovri?
• What is Gocovri used to treat?
• Why should you not discontinue amantadine?
• How long does it take for amantadine to start working?
• Why was amantadine discontinued for flu?
• What symptoms does amantadine treat?
• What is Gocovri (amantadine) and how does it work?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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