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Amantadine is an antiviral agent with mild antiparkinsonian activity. Amantadine was used in the early 2000s for Influenza A treatment. However, high levels of resistance have emerged recently, initially from Asia and now in North America. As of 2011, the CDC does not recommend treatment or prophylaxis of influenza A due to the high levels of resistance. Amantadine is now used mostly for Parkinson disease. This activity outlines the indications, contraindications, activity, adverse drug reactions, warning, precautions, toxicity, and limitations of amantadine in the clinical setting as relates to the essential points necessary for members of an interprofessional team managing the care of patients with Parkinson disease. Objectives: Identify the proper indications for amantadine therapy. Describe the mechanism of action of amantadine. Review the potential adverse effects of amantadine. Outline the importance of collaboration and coordination among the interprofessional team and how it can enhance patient care when dosing amantadine to improve patient outcomes for Parkinson patients. Access free multiple choice questions on this topic.

There currently is no minimum toxicity dose listed. The limitation for increased doses beyond 400 mg per day is due to CNS effects. It is essential to know the patient's history of mental illness and seizures before proceeding with therapy. Toxicity may manifest as acute psychosis, cardiovascular toxicity, coma, and/or death. Although there is no antidote for amantadine, side effects resolve with discontinuation of usage. Some preparations of the drug may contain propylene glycol. Large amounts of propylene glycol can potentially be toxic and cause hyperosmolality, lactic acidosis, respiratory depression, and seizures. In addition, Amantadine toxicity is a concern in patients with severe renal impairment, as 90% of the dose administered orally is excreted unchanged in the urine.[12]

Amantadine was once widely prescribed for Parkinson disease and even influenza. However, there are many more effective drugs on the market, and the use of amantadine has declined. Nevertheless, nurse practitioners, physician assistants, or primary care providers who prescribe this agent should closely monitor the patient for adverse effects. Also, the patient's renal function and mental status require monitoring. Amantadine can increase the risk of depression and lower the threshold for seizures, so nurses should explicitly query and search for this information on patient intake. Irreversible changes in the liver can occur, and hence liver enzymes require monitoring at the same time. Pharmacists should examine the patient's medical record, look for drug interactions, verify dosing, and express any concerns to the prescriber. With an interprofessional team approach to healthcare, amantadine therapy can be most effective in those cases where it is still useful, and other agents can substitute for it with a collaborative assessment of the patient's needs and regimen. [Level V]