Lecture on chloroquine medicine poisoning

2021-08-08 06:09 PM

Chloroquine is soluble in the acidic environment of the stomach, rapidly absorbed completely in the duodenum and the first part of the jejunum, so it can cause sudden cardiac arrest


Chloroquine, Aralen, Nivaquine, Delagyl is a common antimalarial drug with the chemical name Amino-4-Chloro-7-Quinoline.

Chloroquine is a widely used antimalarial drug in Africa and Southeast Asia, so poisoning often occurs. It is the third leading cause of acute poisoning, after sleeping pills and insecticides. Most cases of poisoning are caused by drinking to commit suicide, in a few cases by mistaken or mistaken dosage.

Absorption - metabolism

Chloroquine is soluble in the acidic environment right in the stomach, rapidly absorbed completely in the duodenum and first jejunum (80-90% in 1-2 hours after oral administration) so it can cause sudden cardiac arrest within 1- 4 hours after drinking. In the blood, the drug binds to plasma proteins. The remaining 1/3 is in the free body, then distributed in muscle, kidney, liver, heart, lung and lowest in brain cells, bone marrow (the part concentrated in tissues is 1000 times more than the rest in blood. It is the plasma concentrations of chloroquine that are toxic to the myocardium, not the concentrations of chloroquine in the tissues, that chloroquine toxicity rarely persists beyond 48 hours.

Elimination in the urine is intact but slow (10-12% after 48 hours), it takes 10 days to clear under normal conditions without renal failure. Elimination is increased when the urine is acidic and decreases when the urine pH is alkaline.

Pharmacology and toxicity

Chloroquine, like quinidine, acts at the cellular level, on nucleoproteins, especially on the cardiac muscle and nerve cells. Inhibitory effect on cell metabolism due to inhibition of DNA and RNA polymerase activities. On the heart, the drug reduces myocardial excitability, decreases myocardial conduction, prolongs the refractory period, widens QRS due to inhibition of Na+, K+, Ca++ pumps. The uterus reduces muscle contractions. In women with chloroquine abortion, the uterus does not contract to expel the fetus, causing toxicity to the mother, often leading to death.

The toxic dose depends on the person, 2g can also be fatal in a pregnant woman.

Diazepam, Barbiturates are antagonists of Chloroquine.

The dose of 180 mg Chloroquine/liter is a dose that inhibits muscle activity. The minimum dose of Diazepam to re-establish muscle activity is 20 mg/l (50% muscle re-establishment).


It should be noted that cardiac arrest can occur suddenly, very early in a fully awake patient, and resuscitation measures are often unsuccessful.

Consciousness disorder

Headache, lethargy appear 10-30 minutes after taking. Then he struggled, mildly comatose, sometimes with intermittent tremors.

Severe: Deep coma, loss of reflexes, drop in blood pressure, and possibly sudden cardiac arrest.

Sometimes there is a hardening of the jaw.

Nervous disorders

Eyes: Blurred color, double vision, decreased vision (due to accommodation disorder), sometimes transient blindness.

Nervous disorders VIII: Dizziness, tinnitus, hearing loss.

Cardiovascular disorders

At first, the heart rate is fast 90-100 beats/minute, blood pressure is normal. Then the blood pressure gradually drops with bradycardia or clamping blood pressure with cyanosis of the extremities.

Cardiac arrest is often preceded by sinus tachycardia. Sometimes there is a sudden cardiac arrest without warning.


Flat T.

QRS dilation, the degree of dilatation has prognostic significance (>0.1 seconds is severe)

QT prolongation but difficult to identify because T is flattened.

Possible arrhythmias: Atrioventricular conduction disturbances, sinus tachycardia, ventricular extrasystoles, ventricular tachycardia, torsades de pointes... and may cause sudden cardiac arrest.

Respiratory disorders

Shortness of breath, tachypnea, peripheral cyanosis, sudden apnea without warning.

Digestive disorders

Vomiting often occurs soon after ingestion to help flush toxins out, but there is a risk of aspiration into the respiratory tract.

Urinary disorders

You may urinate less.


Definite diagnosis

Medical history.

Clinical symptoms.


Tests for toxins in:

Gastric: toxic threshold of 10 mmol / L.

Blood: 25 mmol / L.


Ion map:

Blood K+ decreases due to intracellular K+.

Level diagnosis

Severe: Oral dose > 3 g, maximum blood pressure £90 mmHg, QRS ³0.1 seconds.

Death: Oral dose > 5 g, maximum blood pressure £80 mmHg, QRS ³0.12 seconds. Pre-existing heart disease increases the risk of death.


Eliminate Poison

Through the digestive tract:

Gastric lavage as soon as possible after intubation and 1 dose of Diazepam to reduce the risk of Mendelson's syndrome, cardiac arrest, and sudden apnea.

Via urine:

Not important.

Nervous disorders

Mild: Diazepam 10mg 1 tube (IV) x 2-3 times/day.

Severe: The first dose is 2mg/Kg (IV) for 30 minutes, then maintain 1-2mg/Kg body weight/day x 2-3 days. Stop when hemodynamically stable on quantitative ECG and blood Chloroquine <10 mmol / L.

Supportive treatment

Seizures: Diazepam.

Respiratory failure: intubation, help to breathe.

Circuit failure, hypotension: Intravenous Adrenaline 0.25 mg/kg/min, can increase the dose if needed.

Cardiac arrest, respiratory arrest, circulatory resuscitation.