Amantadine Use in Elderly Patients with Extrapyramidal Symptoms

Dosing Considerations for Patients > 65 years

The daily dose of amantadine in individuals older than 65 years should be limited to ≤ 100 mg because renal function declines with age, increasing the risk of drug accumulation. [CDC MMWR Recommendations] [1][2][3][4]
For some older adults, the dose should be further reduced according to the patient’s measured renal function (e.g., creatinine clearance). [CDC MMWR Recommendations] [5][6]
The standard adult regimen of 200 mg daily is associated with a significantly higher incidence of central‑nervous‑system (CNS) side effects (e.g., confusion, hallucinations) in the elderly. [American Academy of Family Physicians] [7][8]

CNS toxicity (visual hallucinations, delirium, confusion, nervousness, anxiety, insomnia) occurs more frequently in older patients receiving amantadine. [American Academy of Family Physicians] [7][8]
A dose reduction is recommended for patients whose creatinine clearance is < 50 mL/min/1.73 m², to mitigate the risk of accumulation and toxicity. [CDC MMWR Recommendations] [1][2][3][4][5][6]

Initiate therapy with 100 mg once daily (instead of the usual 200 mg adult dose) when treating drug‑induced extrapyramidal symptoms in a 74‑year‑old. [American Academy of Family Physicians] [7][8]
Assess renal function (e.g., estimate creatinine clearance) before starting amantadine and adjust the dose accordingly. [CDC MMWR Recommendations] [1][5]
Monitor closely for CNS adverse effects, especially confusion, hallucinations, and delirium, during the first weeks of treatment. [American Academy of Family Physicians] [7][8]