Serial measurement of glyphosate blood concentration in a glyphosate potassium herbicide-intoxicated patient: A case report.

INTRODUCTION: This report describes changes in blood and urine concentrations of glyphosate potassium over time and their correlations with clinical symptoms in a patient with acute glyphosate potassium poisoning. CASE REPORT: A 67-year-old man visited the emergency center after ingesting 250 mL of a glyphosate potassium-based herbicide 5 h before. He was alert but presented with nausea, vomiting, and bradyarrhythmia with atrial fibrillation (tall T waves). Laboratory findings revealed a serum potassium level of 6.52 mEq/L. After treatment with an injection of calcium gluconate, insulin with glucose, bicarbonate, and an enema with polystyrene sulfonate, the patient's serum potassium level normalized and the bradyarrhythmia converted to a normal sinus rhythm. During admission, the blood and urine concentration of glyphosate and urine aminomethylphosphonic acid (AMPA, a glyphosate metabolite) was measured at regular time intervals. The patient's glyphosate blood concentration on admission was 11.48 mg/L, and it had decreased rapidly by 16 h and maintained about 1mgl/L by 70 h after admission. Urine glyphosate and AMPA levels had also decreased rapidly by 6 h after admission. DISCUSSION: Glyphosate potassium poisoning causes hyperkalemia. Blood concentrations of glyphosate were decreased rapidly by 16 h after admission, and urine concentrations were also decreased by 6 h after admission.