Associate Professor Penn State Health Hummelstown, Pennsylvania, United States
Case Diagnosis: Amantadine Toxicity Secondary to Acute Kidney Injury
Case Description: 86-year-old female with history of type 2 diabetes and atrial fibrillation on warfarin who presented with acute-onset dizziness, nausea, and drowsiness. Workup revealed a left cerebellar hemorrhage with midline shift and brainstem compression, requiring emergent craniotomy and external ventricular drain placement. Hospitalization course was complicated by post-operative left frontal and occipital lobe infarcts. At acute inpatient rehab, she continued to have decreased arousal, so Amantadine was started for neurostimulation. Her cognitive status and participation in therapies improved. At time of discharge, she had acute altered mental status presenting as disorientation, dysarthria, impulsivity, and limb tremors. Workup ruled out infection. She was treated with IV fluids for acute kidney injury (AKI); however, patient remained confused. Repeat CT head was negative for acute findings. After medication review, Amantadine was discontinued. Her mentation returned to baseline within seven days of Amantadine cessation. She was discharged to sub-acute rehabilitation facility.
Discussions: Amantadine, with its dopaminergic properties, can be used in patients with stroke as a neurostimulant to promote arousal and cognition. However, its dosing and adverse effects should be carefully considered in cases of renal impairment due to its renal excretion before starting the medication. Due to AKI, the patient in this case experienced hallucinations, irritability, and tremors consistent with Amantadine toxicity.
Conclusions: This case highlights the use of Amantadine as a neurostimulant in patients with stroke, along with its potential for adverse effects in cases of renal impairment.