Investigators reported a fatal case of transdermal ivermectin poisoning, representing a documented instance with confirmed plasma drug concentrations. The patient, a female patient in her early 40s, had applied a veterinary 1% ivermectin solution to her back and waist nightly for 1 month to manage sarcoptic scabies after standard therapy proved ineffective. She used approximately 200 mL per application under occlusion with plastic film, creating extended dermal exposure across ulcerated skin. One week prior to hospital admission, the patient experienced nausea, vomiting, abdominal pain, and anorexia but continued applying the drug. She was found unconscious approximately 1 hour before admission, and upon arrival, her peripheral oxygen saturation was 70%; her Glasgow Coma Scale score was E1V1M1; cyanosis was present in the limbs; and scattered ulcers were noted on the face, lower extremities, back, and waist.
Initial evaluation demonstrated acute respiratory failure requiring intubation, severe metabolic acidosis with a potential of hydrogen of 6.93, hyperlactatemia of 15 mmol/L, renal impairment with creatinine of 122 μmol/L, and significant coagulopathy—including a D-dimer of 21.8 mg/L FEU. Chest computed tomography (CT) highlighted right lower lobe consolidation, and head CT demonstrated diffuse cerebral edema with sulcal effacement. Toxicological screening using liquid chromatography–tandem mass spectrometry was performed 2 days following admission and showed an ivermectin concentration of 27 ng/mL; therapeutic dosing usually results in blood concentrations less than 2 ng/mL or undetectable. Screening for amitraz and sedative-hypnotics was negative.
Treatment consisted of hemoperfusion, intubation with mechanical ventilation, targeted temperature management with core temperature maintained at 36°C, osmotherapy using 20% mannitol at 1 g/kg every 6 hours, and latamoxef at 1 g every 12 hours for 7 days to manage lung infection. Despite these interventions, the patient’s neurologic status didn't improve. Repeat imaging showed progression to pseudosubarachnoid hemorrhage and absence of intracranial arterial flow on CT angiography, consistent with cerebral circulatory arrest. The patient met criteria for clinically presumed brain death under national guidelines, and life-sustaining therapy was withdrawn at the request of the family.
“The patient continued using ivermectin, which eventually led to severe cerebral edema, resulting in irreversible damage to the central nervous system,” noted lead study author He Yin, of the Department of Emergency at the Beijing Tsinghua Changgung Hospital at the School of Clinical Medicine at Tsinghua University in China, and colleagues.
The authors report no conflicts of interest.