Amantadine finds use as an active ingredient in influenza A as well as Parkinson’s disease. It is available by prescription and under various trade names, predominantly in tablet form and also as an infusion.
What is amantadine?
Amantadine finds use as an active ingredient in influenza A as well as Parkinson’s disease. The drug amantadine is a derivative of adamantane. It is suitable for the treatment of influenza A type flu infection as well as Parkinson’s disease. Thus, it belongs to the groups of viral and antiparkinsonian drugs. It is mainly prescribed in tablet form, containing 100 mg, 150 mg or 200 mg of the substances amantadine hydrochloride or amantadine hemisulfate. The dose and dosage form are determined individually by the treating physician. Another possible application under discussion is the presumed positive influence of amantadine in the treatment of withdrawal symptoms in cocaine addicts. Furthermore, the drug is used in the treatment of multiple sclerosis.
Pharmacological effects
The active ingredient amantadine inhibits the release of viral genetic information into the cytoplasm of the host cell, thus blocking the M2 ion channel protein present in the cell membrane. However, this effect can only be achieved with a therapeutic dosage of amantadine in influenza A viruses. A possible mutation of the M2 gene may result in viral resistance to amantadine. For effective control of influenza B viruses and other such viruses, amantadine would have to be overdosed, which is why it is not used here. The exact mechanism of action of amantadine in Parkinson’s disease is not yet completely clear. It is assumed that, as a weak antagonist of the MNDA glutamate receptor type, it increases the release of dopamine and thus prevents its reuptake. It thus has a positive effect in the treatment of Parkinson’s disease. It is also useful in drug-induced parkinsonism and in combination with L-DOPA for the treatment of L-DOPA-induced dyskinesia. A reduction in parkinsonian symptoms can be observed after amantadine administration.
Medicinal application and use
Amantadine inhibits the multiplication of viruses and relieves the symptoms of Parkinson’s disease. The drug amantadine can be used as a preventive measure in unvaccinated as well as vaccinated individuals when there is a risk of infection with influenza virus type A. Amantadine can reduce the duration of fever by about one day in cases of flu already caused by influenza A viruses. In addition, it reduces the feeling of sickness that is otherwise pronounced in a “real” flu. Amantadine is best prescribed as soon as possible after the onset of influenza in order to develop its full potential. It should be taken for one to two days beyond that after symptoms of illness have ended. Amantadine for the prevention and treatment of type A viral influenza should not be used in children until they are 5 years of age or older. In the elderly, the drug should be dosed cautiously, especially if they are delirious patients and those with states of agitation and confusion. Pregnant and breastfeeding women are advised against treatment with amantadine. In Parkinson’s disease therapy, amantadine reduces the increased activity of acetylchoninergic striatal interreurons typical of this condition. In addition, as a weak NMDA receptor antagonist, it inhibits the action of glutamatergic projections from the cortex. It is true that the exact mode of action of amantadine in the therapy of Parkinson’s disease has not yet been fully elucidated. Nevertheless, the results are convincing. Amantadine noticeably alleviates the unmistakable symptoms associated with this disease. It reduces tremor – tremor, it reduces movement disorders – akinesia, and it reduces physical rigidity – rigor.
Risks and side effects
When taking amantadine, patients may experience several side effects, the frequency of which is described as occasional:
- Mood disturbances such as euphoria or depression.
- Perceptual impairments such as confusion, nightmares, or hallucinations
- Sleep disturbances
- Urination disorders
- Nausea, vomiting or diarrhea
- Blood pressure fluctuations
Driving and operating machinery may be impaired due to decreased alertness and possibly decreased vision during therapy with amantadine.Due to complex interactions with numerous medications, the attending physician should be informed about the use of other preparations. Likewise, amantadine should be used with caution in multiple chronic and acute conditions. Amantadine is contraindicated in:
- Hypersensitivity to the active substance
- Myocardial insufficiency in the stage NYHA IV
- Cardiomyopathy and myocarditis
- AV block of II and III degree
- Bradycardia
- Congenital QT syndrome and similar cardiac diseases.
- Cardiac arrhythmia
- Lowered blood calcium and magnesium levels
