SHM Converge Scientific Abstract ePoster Gallery-Ams in the Cns: Amantadine Toxicity

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This case describes amantadine toxicity in a 63-year-old woman with end-stage renal disease (ESRD), atrial fibrillation, cirrhosis, and Parkinson’s disease. She presented after an unwitnessed fall with persistent encephalopathy and altered mental status. Workup for stroke, seizure, and infection was negative, but her ECG showed wide QRS complexes. Two weeks before admission, she had increased her amantadine dose to 100 mg three times daily without renal adjustment, leading to presumed unintentional overdose.<br /><br />The patient’s condition worsened, requiring intubation for airway protection. Her hospital course was further complicated by pneumonia, sepsis, and septic shock requiring vasopressors and antibiotics. Despite supportive care, she continued to decline, and the family ultimately chose comfort-focused care. She died 23 days after admission.<br /><br />The report emphasizes that amantadine is largely renally cleared, with about 90% excreted by the kidneys. In patients with moderate to severe renal dysfunction, especially those with ESRD on dialysis, amantadine should be used very cautiously because it is poorly removed by dialysis. Risk factors for toxicity include older age, renal impairment, and dose escalation without adjustment.<br /><br />Amantadine toxicity can present with altered mental status, seizures, anticholinergic symptoms such as dry mouth, urinary retention, and mydriasis, respiratory failure, and cardiotoxicity including QRS widening and arrhythmias. There is no specific antidote; treatment is primarily supportive. The key takeaway is to adjust dosing carefully in renal impairment and recognize that overdose may present with neurologic and cardiac symptoms.

Asset Subtitle

Valeria G. Hanson

Meta Tag

Author List Abu Baker Sheikh, Mario Flores, Valeria G. Hanson

Category Clinical Vignettes

Concept Amantadine

Concept Amantadine Toxicity

Concept Supportive Care

Concept Renal Dysfunction

Concept Overdose

Distinguished Non-Finalist

Presenter Organization University of New Mexico

Presenting Author Valeria G. Hanson

Track Adult

Keywords

amantadine toxicity

end-stage renal disease

altered mental status

wide QRS complexes

renal dose adjustment

Parkinson’s disease

dialysis

cardiotoxicity

encephalopathy

supportive care

Amantadine

Amantadine Toxicity

Supportive Care

Renal Dysfunction

Overdose