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Amantadine - Uses, Dosage, Side Effects, and More

Published on Jun 27, 2022 and last reviewed on Jul 06, 2022   -  15 min read


Amantadine is an antidyskinetic and antiviral drug used for Parkinson’s disease and respiratory infections respectively. Read this article for more details.



Amantadine belongs to a class of medications referred to as adamantanes. It is used to treat the following conditions:

Amantadine is available in a variety of dosage forms, including:

How Does Amantadine Work?

Uses of Amantadine:

Extrapyramidal reactions are side effects of antipsychotic medications. They typically occur as symptoms such as involuntary muscle contractions, involuntary facial movements, tremors, muscle stiffness, and jerky movements.

Dosage Restrictions:

Initial Dose:100 mg daily.

Increase in Dosage:

Time to Increase: 1 to a few weeks after the initial dose.

Increase To:

Concomitant use of Amantadine with anticholinergic anti-Parkinson drugs may provide better results than solo therapy with either of the two. Amantadine dosage may either be 100 mg daily or twice daily, while the dosage of drugs like Levodopa may be increased until an optimal concentration is obtained, with good results.

Special Considerations:

Dosage Adjustment:The following patients may require a reduction in drug dosage:

Drug Safety Concerns:

Warnings and Contraindications:


Warnings and Precautions:

For Patients:

What Is Parkinson’s Disease?

Parkinson’s disease is a disorder of the central nervous system (specifically the brain) that affects movement. It causes uncontrollable movements in the form of tremors and is also characterized by shaking, imbalance and uncoordinated movements, and muscle stiffness. The symptoms usually worsen over time and can manifest as the inability to walk or talk properly. It occurs due to damage in the brain's nerve cells, which can cause dopamine levels to fall and lead to tremors, stiffness, and imbalance.

What Is Influenza A Respiratory Illness?

Influenza A is a virus that causes influenza (or the flu), a highly contagious viral illness. It can be especially concerning among vulnerable populations such as pregnant women, people with weak immune systems or chronic diseases, older populations, and young children. It is usually spread through airborne respiratory droplets from coughing, sneezing, saliva, and touching contaminated surfaces.

Why Is Amantadine Prescribed for Parkinsonism?

Amantadine has mild anti-Parkinsonian activity and decreases tremors, stiffness, and slowness of movement. Concurrent use of Amantadine with Levodopa allows for the conversion of Levodopa to Dopamine.

Why Is Amantadine Prescribed for Viral Illnesses Caused by Influenza A?

Amantadine is capable of decreasing not only the symptoms of influenza A illness but also reducing the severity of symptoms such as fever. However, high resistance levels demonstrated in cases from Asia and North America have led to a decline in the prescription of this drug for respiratory illnesses. The Centers for Disease Control (CDC) no longer recommends the use of Amantadine for prophylactic (preventive) or therapeutic (treatment) purposes in influenza A-origin respiratory illnesses.

How Should You Take Amantadine?

Amantadine is available in the following standard concentrations:

Influenza A:

Prophylaxis: Continue the same dosage until influenza season is over.

Parkinson’s Disease:

What Should You Discuss With Your Doctor Before Beginning Treatment With Amantadine?

What Side Effects Can You Expect With Amantadine?

The side effects of amantadine are limited. They include the following:

Can You Stop Taking Amantadine Without Your Doctor’s Approval?

Never attempt to discontinue the use of the drug yourself. Discontinuation of Amantadine has been known to cause high fever and confusion in patients. The symptoms are similar to those in neuroleptic malignant syndrome (NMS) and usually occur following sudden withdrawal or rapid dose reduction. This condition is referred to as withdrawal-emergent hyperpyrexia (high fever) and confusion.

Can You Stop Taking Amantadine Without Your Doctor’s Approval?

How Should You Take Amantadine?

Are There Any Dietary Restrictions to Consider When Taking Amantadine?

No dietary restrictions exist in relation to Amantadine consumption except for alcohol restrictions. The consumption of alcohol is not recommended when taking Amantadine as it contributes to increased CNS effects like orthostatic hypotension, dizziness, and confusion.

How Should You Store and Dispose of Amantadine?

What Can You Do In Case of Overdose?

What Should You Do if You Miss a Dose?

What Else Should You Keep in Mind?

Amantadine can cause you to feel sleepy while actively engaging in daily activities. If you are prescribed Amantadine, wait several days to assess the emergence of these symptoms before performing tasks such as the operation of heavy machinery, or driving.

For Doctors:





Active Ingredient:

Inactive Ingredients:

Active Ingredient:

Inactive Ingredients:

Active Ingredient:

Inactive Ingredients:


Mechanism of Action:

The antiviral mechanism of action of Amantadine is not entirely clear. However, it is understood that Amantadine inhibits or interrupts viral replication. The transmembrane domain of the viral M2 protein is interrupted by Amantadine, ensuring that viral nucleic acids are unable to enter the host cell. It also interferes with the assembly of influenza A virus isolates from the H1N1, H2N2, and H3N2 subtypes during virus replication.

The anti-Parkinsonian action of Amantadine relies on its effects on dopamine neurons. It is a weak antagonist of the NMDA (N-methyl-D-aspartate) receptor (a glutamate receptor and ion channel that regulates memory and brain aging). Its antagonistic activity increases the release of dopamine while also preventing its reuptake.


Special Considerations:

Drug Interactions:

Drug Release:

Inhibitory Activity:

Amantadine has no inhibitory activity against cellular transporters, including:

Amantadine does not inhibit the enzyme activity of the drug-metabolizing cytochrome P450 isoforms, including:

Substrate Activity:

Amantadine is not a substrate of the following:

Amantadine is a poor substrate of the following:

Clinical Trials:

Parkinson’s Disease:A study conducted in the United States and Canada evaluated the efficacy of Amantadine ER capsule in patients with dyskinesia associated with Parkinson’s disease.

Study Design:

Patients were also given a stable dose of Levodopa. In addition, they were given dopamine agonists and/or MAO-B inhibitors.

Baseline Scores:


At Week 12:

Other Off-Label Uses of Amantadine:

The use of Amantadine in diseases other than those explicitly approved by the FDA has been suggested. These non-FDA approved indications include:

Patient Counseling Information:


Last reviewed at:
06 Jul 2022  -  15 min read




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