Details

Amantadine is an antiviral medicine that blocks the actions of viruses in your body. It is used to treat and prevent influenza A (a viral infection). Amantadine may not be effective during every flu season because certain strains of influenza virus may be resistant to this medicine. Amantadine is also used to treat Parkinson's disease and "Parkinson-like" symptoms such as stiffness and shaking that may be caused by the use of certain drugs. An amantadine overdose can prove to be fatal.

Typical Uses

Amantadine is used to prevent or treat a certain type of flu (influenza A). If you have been infected with the flu, this medication may help make your symptoms less severe and shorten the time it will take you to get better. Taking amantadine if you have been or will be exposed to the flu may help to prevent you from getting the flu. This medication is an antiviral that is believed to work by stopping growth of the flu virus. This medication is not a vaccine. To increase the chance that you will not get the flu, it is important to get a flu shot once a year at the beginning of every flu season, if possible.

Side Effects

Get emergency medical help if you have signs of an allergic reaction such as hives, difficult breathing, swelling of your face, lips, tongue, or throat. Contact your doctor if you have shortness of breath (even with mild exertion), swelling in your hands or feet, painful or difficult urination, depression, agitation, or aggression, behaviour changes, hallucinations, thoughts of hurting yourself, a seizure (convulsions) or severe nervous system reaction, very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Drug Interactions

• Amantadine+tramadol- Tramadol may rarely cause seizures, and combining it with other medications that can also cause seizures such as amantadine may increase that risk.

• Amantadine+bupropion- Using amantadine together with bupropion can increase the risk of seizures. This may be more likely to occur in older adults or those with a history of seizures or other risk factors for seizures.

• Amantadine+iohexol- Before you undergo any imaging procedure where iohexol may be injected directly into the spine let your doctor know if you are currently being treated with amantadine. Injection of iohexol into the spine can sometimes cause seizures, and the risk may be increased if you are also using other medications that can cause seizures such as amantadine.

• Amantadine+metrizamide- Before you undergo any imaging procedure where metrizamide may be injected directly into the spine let your doctor know if you are currently being treated with amantadine. Injection of metrizamide into the spine can sometimes cause seizures, and the risk may be increased if you are also using other medications that can cause seizures such as amantadine.

Mechanism of action

The exact way in which amantadine works in Parkinson's disease is not fully understood. However, it would appear to have three actions that allow it to control some of the symptoms of this disease. The first is that it increases the activity of a neurotransmitter called dopamine in the brain.

Neurotransmitters are natural body chemicals that are involved in transmitting messages between nerve cells. Dopamine is known to be reduced or absent in the brains of people with Parkinson's disease, and this is thought to be the main cause of the disease's symptoms. By increasing the release of dopamine in the brain, amantadine replaces some of the lost dopamine and therefore reduces some of the symptoms of the disease.

Amantadine also has a mild anticholinergic effect. This means it prevents the activity of a neurotransmitter called acetylcholine. There is normally a balance between the activity of dopamine and the activity of acetylcholine in the brain. However, in Parkinson's disease, the deficiency of dopamine causes over-activity of acetylcholine. By reducing the activity of the acetylcholine, amantadine helps restore the balance of acetylcholine and dopamine in the brain and this also helps reduce some of the symptoms.

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