Are 1–2 dangerous? Chloroquine and hydroxychloroquine exposure in toddlers

Ingestion of 1-2 tablets of chloroquine or hydroxylchloroquine is thought to predispose children under 6 years of age to serious morbidity and mortality. The actual risk to the toddler and appropriate guidelines for care remain unclear at a time when both medications are therapeutically utilized as anti-inflammatory agents in addition to their main use as anti-parasitics. A review of the literature and data from the American Association of Poison Control Centers reveals instances where exposure to as little as 1-2 tablets of chloroquine resulted in serious consequences. Based on these findings, ingestions of greater than 10 mg/kg of chloroquine base or unknown amounts require triage to the nearest health care facility for 4-6 h of observation. There is very limited data on pediatric hydroxychloroquine overdoses and no reports of toxicity from 1-2 pills, but given its similarity to chloroquine, it also should be considered potentially toxic at small doses. Thus, similar recommendations should be followed for triage after accidental hydroxychloroquine overdose.

Demonstration of a chloroquine fatality after 10-month earth-grave

A 19-year-old woman suspect of a suicidal drug intoxication was exhumed after a 10-month earth-grave, because the police was accused of manslaughter and neglected help by the relatives of the deceased. Toxicologic analysis revealed as the cause of death an acute chloroquine intoxication. An expert opinion had to deal with the question if the woman would have been saved if the police had appeared earlier. Therefore the duration of agonal period after suicidal chloroquine ingestion was important. An estimation of the time since death was possible on the one hand ex-post from the development of cadaveric changes and supravital reactions and on the other hand, based on premortal changes detectable on the body together with the findings of the authorities. Taking into account all evidence the woman was probably already dead at or prior to the arrival of the police (110 min after ingestion), at least this could not be excluded. Chloroquine has to be considered to be useful for fatal poisoning, which is also recommended in some publications on methods to commit suicide.

Disturbances of potassium homeostasis in poisoning

Unless renal function is impaired or rhabdomyolysis is severe, hyperkalemia is a relatively uncommon metabolic complication of poisoning. In contrast, marked hypokalemia is a more common problem and may have serious sequelae. Most potassium disturbances in acute poisoning are due to disruption of extra-renal control mechanisms, notably the activity of Na+/K+ ATPase and K+ channels. Hypokalemia occurs because of increased Na+/K+ ATPase activity (e.g. beta 2 agonist, theophylline or insulin poisoning), competitive blockade of K+ channels (e.g. barium or chloroquine poisoning), gastrointestinal losses and/or alkalosis. Hyperkalemia follows inhibition of Na+/K+ ATPase activity (e.g. by digoxin), increased uptake of potassium salts, disruption of intermediary metabolism (e.g. cyanide poisoning), activation of K+ channels (e.g. fluoride poisoning), and the presence of acidosis and rhabdomyolysis, particularly if the latter is complicated by renal failure. Hypokalemia results in generalized muscle weakness, paralytic ileus, ECG changes (flat or inverted T waves, prominent U waves, ST segment depression) and cardiac arrhythmias (atrial tachycardia +/- block, AV dissociation, VT, VF). Hyperkalemia is associated with abdominal pain, diarrhea, muscle pain and weakness, ECG changes (tall peaked T waves, ST segment depression, prolonged PR interval, QRS prolongation) and cardiac arrhythmias (VT, VF). Significant disturbances of potassium homeostasis are often unrecognized and may cause considerable morbidity and mortality. Prompt recognition and appropriate treatment of these disturbances could be life-saving.