Treatment of poisoning

Patients with severe poisoning may require mechanical ventilation and/or treatment for cardiovascular collapse. If consciousness is impaired, constant monitoring and restraint may be required.

Treatment for poisoning by various substances is presented in tables. In all but the mildest cases, consultation with the Poison Control Center is indicated.

Typical specific antidotes

Toxin	Antidote
Paracetamol	Acetylcysteine
Anticholinergics	Physostigmine*
Benzodiazepines	Flumazenil*
Beta-blockers	Glucagon
Calcium channel blockers	Calcium preparations, intravenous administration of large doses of insulin with intravenous glucose infusions
Carbamates	Atropine, protamine sulfate
Cardiac glycosides (digoxin, digitoxin, oleander, foxglove)	Digoxin-specific PAF fragment
Ethylene glycol	Ethanol, fomepizole
Heavy metals	Chelates)
Iron	Deferoxamine
Methanol	Ethanol, fomepizole
Methemoglobin formers (aniline dyes, some local anesthetics, nitrates, nitrites, phenacetin, sulfonamides)	Methylene blue
Opioids	Naloxone
Organophosphorus compounds	Atropine, pralidoxime
Tricyclic antidepressants	NaHC0 3
Isoniazid	Pyridoxine (vitamin B6)

Use is controversial. FAT - fractionated antibodies.

First aid for poisoning

Treatment of any poisoning begins with restoring airway patency and stabilizing breathing and blood circulation.

In case of apnea or obstruction of the upper respiratory tract (foreign body in the oropharynx, decreased pharyngeal reflex), endotracheal intubation is indicated. In case of respiratory depression or hypoxia, oxygen therapy or artificial ventilation is necessary.

In patients with apnea, after ensuring the upper airway is patent, intravenous naloxone (2 mg in adults, 0.1 mg/kg body weight in children) should be tried. In opioid addicts, naloxone may hasten the onset of withdrawal, but it is better than apnea. If respiratory failure persists despite naloxone, tracheal intubation and mechanical ventilation are indicated. If breathing is restored by naloxone, the patient should be monitored, and if respiratory depression recurs, another bolus of intravenous naloxone or mechanical ventilation can be tried. The effectiveness of continuous naloxone infusion for maintaining breathing has not been proven.

A patient with altered consciousness must have his blood plasma glucose concentration determined immediately, or glucose administered intravenously (50 ml 50%)

Chelation therapy

Chelating agent*	Metal	Doses**
Unithiol, 10% oil solution	Antimony, arsenic, bismuth, chromates, chromic acid, chromium trioxide, copper salts, gold, mercury, nickel, tungsten, zinc salts	3-4 mg/kg deep intramuscularly every 4 hours on the 1st day. 2 mg/kg deep intramuscularly every 4 hours on the 2nd day. 3 mg/kg deep intramuscularly every 4 hours on the 3rd day, then 3 mg/kg intramuscularly every 12 hours for 7-10 days until recovery
<3% sodium calcium edetate solution	Cadmium, lead, zinc, zinc salts	25-35 mg/kg intravenously slowly (over 1 hour), every 12 hours for 5-7 days, the next 7 days without the drug, then repeat
Penicillamine	Arsenic, copper salts, gold, mercury, nickel, zinc salts	20-30 mg/kg per day in 3-4 doses (usually the initial dose is 250 mg 4 times a day), the maximum dose for adults is 2 g/day
Succimer	Arsenic, occupational poisoning in adults. Bismuth. Lead, if the child has a blood drug concentration >45 mcg/dL (>2.15 μmol/L). Lead, occupational poisoning in adults. Mercury, occupational poisoning in adults	10 mg/kg orally every 8 hours for 5 days, then 10 mg/kg orally every 12 hours for 14 days

• *Iron and thallium salts are not effectively chelated by these drugs; each requires its own chelating drug.
• **Doses depend on the severity and type of poisoning. Chelating agent of choice solution for adults, 2-4 ml/kg 25% solution for children).

Adults with suspected thiamine deficiency (alcoholics, emaciated patients) are recommended to receive intravenous thiamine at a dose of 100 mg simultaneously with or before the administration of glucose.

Hypotension is treated with intravenous fluids. If this is ineffective, invasive cardiac monitoring may be required to guide fluid therapy and vasopressors. Norepinephrine hydrotartrate (0.5-1 mg/min intravenously) is the drug of choice for treating hypotension in poisoning, but treatment should not be delayed if another vasopressor is available.

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Local decontamination

Any body surface (including eyes) contaminated with poison should be washed with plenty of water or 0.9% sodium chloride solution. Contaminated clothing, as well as socks, shoes, and jewelry should be removed.

Activated carbon

Activated carbon is used frequently, especially when the ingested agent is unknown or multiple. The use of activated carbon is virtually harmless, except in patients with an increased risk of vomiting and aspiration, although this does not reliably affect mortality and complications in general. Activated carbon should be used as early as possible. It absorbs many toxins due to its molecular configuration and large absorption surface. Multiple administrations of activated carbon are effective in poisoning with substances that undergo enterohepatic circulation (phenobarbital, theophylline), as well as with long-acting substances. In severe poisoning, activated carbon can be administered every 4-6 hours, except in patients with intestinal paresis. It is ineffective in poisoning with caustic poisons, alcohol, and simple ions (cyanide, iron, other metals, lithium). The recommended dose of activated carbon for poisoning should be 5-10 times the amount of the toxic substance. However, given that the exact amount of poison is usually unknown, 1-2 g/kg of body weight is usually prescribed (for children <5 years old - 10-25 g, for others - 50-100 g). The drug is prescribed as a suspension. Its taste can cause vomiting in 30% of patients, in which case the drug is administered through a gastric tube. Activated carbon should not be used together with sorbitol and other laxatives due to the risk of dehydration and electrolyte disturbances.

[ 7 ], [ 8 ], [ 9 ]

Gastric lavage

Gastric lavage, although a well-known and seemingly useful procedure, is not routinely used. This procedure does not reduce mortality and complications and has its own risks. Gastric lavage may be recommended within the first hour after life-threatening poisoning. However, most poisonings occur later, and it is also very difficult to determine whether it is life-threatening. Thus, indications for gastric lavage are rare, and in cases of poisoning with caustic substances, this procedure is contraindicated.

If it is decided to perform gastric lavage, the optimal method is lavage. The effect of ipecac syrup + codeine is unpredictable, often causes prolonged vomiting and may not remove a significant amount of poison from the stomach. Complications of gastric lavage include nosebleeds, aspiration, and, rarely, damage to the oropharynx and esophagus.

Lavage is performed by pouring tap water in and out through a gastric tube of maximum diameter (usually >36 Fr in adults or 24 Fr in children) to allow free passage of residual tablets. A patient with altered consciousness or a reduced pharyngeal reflex should be intubated before lavage to prevent possible aspiration. To prevent aspiration when inserting the tube, the patient is placed on the left side with bent legs, the tube is inserted through the mouth. Since lavage in some cases promotes pushing the substance further into the gastrointestinal tract, 25 g of activated charcoal is first introduced through the tube. Then tap water (about 3 ml/kg) is poured into the stomach and aspirated with a syringe, or it flows out by gravity. Lavage is continued until the water is clear (without residual toxic agent); in most cases, 500-3000 ml of water is required. After lavage, a second dose of charcoal - 25 g - is introduced through the tube.

Washing the entire intestines

This manipulation cleanses the gastrointestinal tract and, theoretically, reduces the transit time of pills and tablets through the gastrointestinal tract. A decrease in mortality and complication rates as a result of this procedure has not been proven. Colon lavage is indicated for some severe poisonings with long-acting drugs, substances that are not adsorbed by activated charcoal (heavy metals); when swallowing drug packages (transportation of heroin or cocaine in packages); when bezoars are suspected. During lavage, a commercial solution of polyethylene glycol (non-absorbable) and electrolytes is administered at a rate of 1-2 liters per hour for adults or 25-40 ml/kg per hour for children until clear water appears; the procedure can take several hours or even days. Usually the solution is administered through a gastric tube, although some health workers persuade patients to drink this solution in large volumes.

Alkaline diuresis

Alkaline diuresis accelerates the excretion of weak acids (salicylates, phenobarbital). A solution containing 1 liter of 5% glucose solution or 0.9% sodium chloride solution, 3 ampoules of NaHC0 ₃ (50 mEq each) and 20-40 mEq of K ⁺ can be administered at a rate of 250 ml per hour for adults and 2-3 ml/kg per hour for children. Urine pH is maintained at >8.0. Hypernatremia, alkalosis and hyperhydration are possible, but are usually insignificant. However, alkaline diuresis is contraindicated in patients with renal insufficiency.

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Dialysis

Poisoning with ethylene glycol, lithium, methanol, salicylates, and theophylline may require dialysis or hemoperfusion. These methods are of lesser importance in the following cases:

• the poison has a high molecular weight or polarity;
• the poison is characterized by a large volume of distribution (accumulates in adipose tissue);
• the poison forms a strong bond with tissue proteins (digoxin, phenothiazines, tricyclic antidepressants).

The need for dialysis is usually determined by clinical and laboratory data.

Dialysis options:

• hemodialysis;
• peritoneal dialysis;
• lipid dialysis (removal of fat-soluble substances from the blood);
• hemoperfusion (most quickly and effectively removes certain toxic substances).

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Specific antidotes

Complexing (chelating) drugs are used for poisoning with heavy metals and other substances.

Supportive treatment for poisoning

Most symptoms (agitation, lethargy, coma, cerebral edema, hypertension, arrhythmias, renal failure, hypoglycemia) are treated with conventional supportive measures. Drug-induced hypotension and arrhythmias may respond poorly to conventional treatment. In refractory hypotension, dopamine, epinephrine, and other vasopressors are indicated, or in severe cases, intra-aortic balloon pump and extracorporeal artificial circulation. In refractory arrhythmias, cardiac pacing may be required. Polymorphic ventricular tachycardia (torsades de pointes) can often be treated with 2-4 g of magnesium sulfate intravenously, cardiac rhythm stimulation to suppress ectopic foci of automatism, or isoprenaline infusion. Treatment of seizures begins with the introduction of benzodiazepines, phenobarbital can also be used. In case of severe agitation, the following is necessary:

• high doses of benzodiazepines;
• other sedatives (propofol);
• In severe cases, the use of muscle relaxants and artificial ventilation may be required.

Treatment of hyperthermia often requires physical cooling rather than antipyretics. In cases of organ failure, liver or kidney transplantation may be required.

Hospitalization

The main indications for hospitalization include disturbances of consciousness, persistent disturbances of vital functions, and predictable long-term toxicity of the drug. For example, hospitalization is indicated if the patient has ingested a prolonged-release drug, especially one with a potentially dangerous effect, such as a drug for the treatment of cardiovascular diseases. In the absence of other indications for hospitalization and resolution of poisoning symptoms within 4 to 6 hours, most patients can be discharged; however, if the poisoning was self-inflicted, a psychiatric consultation is necessary.

Prevention of poisoning

In the United States, widespread use of safety-capped drug packaging has significantly reduced fatal poisonings in children <5 years of age. Reducing the number of tablets in a package of over-the-counter analgesics reduces the severity of poisonings, particularly for paracetamol, aspirin, and ibuprofen. Preventive measures include:

• clear labeling of chemical reagents and medicinal products;
• storing medicinal and toxic substances in closed places inaccessible to children;
• timely destruction of expired drugs;
• use of CO detectors.

It is also important to carry out sanitary and educational work on storing chemicals in their original containers (do not store insecticides in bottles from drinks). The use of printed designations on preparations will help prevent errors by both the patient and the pharmacist, doctor.