Therapeutics
Treatment of hydroxychloroquine overdose,☆☆

https://doi.org/10.1053/ajem.2001.25774Get rights and content

Abstract

Hydroxychloroquine overdoses are rarely reported with 7 previous cases found in the English medical literature. We report a case and review the literature. A 16-year-old girl ingested a handful of hydroxychloroquine 200mg, 30 minutes before presentation and presented with tachycardia (heart rate 110 beats/min), hypotension (systolic blood pressure 63 mm Hg), central nervous system depression, conduction defects (QRS = 0.14 msec), and hypokalemia (K = 2.1 meq/L). She was treated with fluid boluses and dopamine, oxygen, and potassium supplementation. Toxicologic tests confirmed the presence of hydroxychloroquine. The patient's hypotension resolved within 4.5 hours, serum potassium stabilized in 24 hours, and tachycardia gradually decreased over 3 days. Although hydroxychloroquine overdoses are very rare, life-threatening hypotension, conduction problems, and hypokalemia can occur within 30 minutes of ingestion. Symptoms are similar to chloroquine and treatment must be implemented quickly and should be modeled after experience with chloroquine overdoses. Treatment modalities need further study, but current recommendations are: (1) diazepam for seizures and sedation; (2) early intubation and mechanical ventilation; (3) epinephrine for treatment of vasodilation and myocardial depression; (4) potassium replacement with close monitoring of levels; (5) charcoal for gastrointestinal decontamination if ingestion occurred within an hour; (6) high dose diazepam for life-threatening symptoms, until more information becomes available. No value was found for serum alkalinization or extracorporeal methods of drug removal. (Am J Emerg Med 2001;19:420-424. Copyright © 2001 by W.B. Saunders Company)

Section snippets

Case report

A 16-year-old girl presented to the emergency department (ED) with a blood pressure of 63 mm Hg by palpation, pulse of 110 beats/min, slurred speech, and drowsiness. History revealed she had taken a handful of her hydroxychloroquine (200 mg), levothyroxine, aspirin, and ibuprofen, 30 minutes before presentation. Fluid boluses brought her blood pressure to 76/32 mm Hg and dopamine was begun at 10 mcg/kg/min. Naloxone 2 mg IV was given without response. She was gastrically lavaged with evidence

Discussion

Hydroxychloroquine overdoses are rarely reported despite the frequent use of this drug. A literature search found only 7 acute overdose reports in the English medical literature.2, 3, 4, 5, 6, 7, 8

The lethal dose is not well established. Twelve grams in a 2-year-old child caused convulsions, cardiorespiratory arrest, and death.5 Twelve grams in a 16-year-old boy was lethal.2 Four grams in a 29-year-old man caused ventricular tachycardia that responded to lidocaine and bretylium. Twelve grams in

Treatment and treatment controversies

Because there is little experience with hydroxychloroquine, the treatment of toxicity is modeled after the treatment for chloroquine (see Table 2).

. Treatment of Chloroquine Overdose

1. Early intubation and mechanical ventilation in patients with signi .cant ingestions or symptoms.
2. Cardiovascular monitoring
3. Epinephrine for hypotension, dysrhythmias, QRS widening, circulatory collapse
4. Diazepam for seizures,dysrhythmias, QRS widening, hypotension, circulatory collapse. LD of 2 mg/kg IV over 30

Conclusion

Hydroxychloroquine overdoses are rare, but very serious. Life-threatening symptoms may occur within 30 minutes with very rapid progression to death within a few hours. The symptoms are similar to chloroquine overdoses. Treatment must be implemented quickly and should be modeled after experience with chloroquine overdoses. Treatment modalities however need further study.

After reviewing the medical literature on hydroxychloroquine and chloroquine overdoses, the following treatment approaches are

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    Address reprint requests to Kathy Marquardt, Pharm D, DABAT, California Poison Control System, Sacramento Division, University of California, Davis Medical Center, 2315 Stockton Blvd, Sacramento, CA 95817.

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