UMEM Educational Pearls

Title: Case: 27 year old with hydroxychloroquine overdose

Keywords: hydroxychloroquine toxicity, overdose (PubMed Search)

Posted: 6/11/2020 by Hong Kim, MD, MPH
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Question

A 27 year-old man with history of rheumatoid arthritis presents to the emergency department after ingestion of hydroxychloroquine (20 tablets of 200 mg/tablet). He complains of nausea/vomiting. He appears lethargic. What is the anticipated hydroxychloroquine toxicity and management?

VS: Temp: afebrile, BP: 95/55 mmHg, RR: 23 breaths/min, O2 saturation: 99%

ECG:

Answer

Signs and symptoms of hydroxychloroquine toxicity includes:

Cardiac: Na & K channel blockade, hypotension/shock, ventricular dysrhythmia
CNS: CNS depression, seizure
Electrolyte: hypokalemia

Patient’s initial ECG showed: QRS: 134 msec; QTc 710 msec. There is also a terminal R wave in aVR. no prior ECG was available.

He experienced intermittent non-sustained V tach.

K was 2.0 mmol/L. other laboratories were normal

Management/course:

ED/Hospital day 1:

The patient was intubated due to lethargy/CNS depression
NaHCO₃ bolus was administered with narrowing of QRS interval to 128 msec with QTc 639 msec.
NaHCO₃infusion
Diazepam 1 mg/kg (80 mg IV bolus plus intermittent IV bolus of 6 mg Q2 hrs [total 39 mg])
Brief requirement of epinephrine infusion at 0.25 mcg/kg/min.

Hospital day 2:

QRS: 92 msec; QTc: 474 msec
Blood pressure normalized

Summary

Cardiac toxicity (Na and K channel blockade) is the primary feature of hydroxychloroquine toxicity
ECG should be obtained to evaluated for evidence of Na channel toxicity – if present, administer NaHCO₃ IV bolus and continous infusion -- and QT prolongation.
High dose diazepam: 1-2 mg/kg IV bolus, followed by continous infusion of 1 – 3 mg/kg/24 hour.
If hypotensive, epinephrine is the preferred pressor of choice.

References

Chai PR et al. Intentional hydroxychloroquine overdose treated with high-dose diazepam: an increasing concern in the COVID-19 pandemic. J Med Toxicol. 2020 PMID: 32514696; PMCID: PMC7278768; DOI: 10.1007/s13181-020-00790-8