[Acute hydroxychloroquine poisoning. The danger of rapid or excessive correction of initial hypokalemia].

INTRODUCTION: Toxic effects of hydroxychloroquine, like chloroquine, include membrane stabilization and hypokalemia, which is correlated with the severity of the overdose. Correction of hypokalemia can expose patients to the risk of ventricular arrhythmia. CASE: A 19-year-old woman who had ingested 6 grams of hydroxychloroquine was admitted to intensive care with severe hypokalemia (1.5 mmol/L on admission). Thirty-six hours after correction of the hypokalemia, circulatory arrest followed ventricular fibrillation. Her potassium level at that time was 5.8 mmol/L. Outcome was favorable after it returned to normal. DISCUSSION: Because its pathogenesis remains debatable, the hypokalemia following hydroxychloroquine poisoning must be corrected with care, even when severe. This correction is difficult, and extracellular transfer of the excess potassium after elimination of the toxin exposes the patient to the risk of ventricular arrhythmia.