Principles of poisoning treatment

Specific (antidote) therapy

This type of treatment is most effective in the early stages of acute poisoning. The main condition for initiating it is a reliably established type of toxin. The mechanisms of action of antidotes vary and depend on the nature of the poison:

• Binding in the gastrointestinal tract: achieved by administering enterosorbents directly into the stomach.
• Inactivation in internal media (chelation): formation of safe soluble complexes with heavy metals for their subsequent excretion in the urine. For this purpose, sodium dimercaptopropanesulfonate, sodium calcium edetate, and penicillamine are used.
• Metabolism inhibition: prevention of toxic metabolite formation in the liver. A classic example is the use of ethanol in methanol or ethylene glycol poisoning.
• Enzyme reactivation: restoration of the activity of blocked enzyme systems (e.g., the use of cholinesterase reactivators in organophosphate poisoning).
• Pharmacological antagonism: competitive interaction of substances at the receptor level (e.g., atropine and acetylcholine, neostigmine methylsulfate).
• Neutralization of animal venoms: reduction of toxic effects through the administration of specific antitoxic sera.

Prevention of absorption and accelerated elimination

To minimize the entry of poison into the systemic circulation, it is necessary to clean the entry pathways as quickly as possible. At the pre-hospital stage, gastric lavage via a tube is critically important. The following measures are also used:

1. Induction of vomiting: mechanical stimulation of the posterior pharyngeal wall or administration of emetics (e.g., apomorphine).
2. Bowel cleansing: binding and elimination of toxins using adsorbents and laxatives. Intestinal lavage (enteroclysis) with the administration of solutions to correct ion imbalance and pH shifts is effective.
3. Removal from skin and cavities: abundant washing of the skin and mucous membranes with water, as well as lavage of the rectum, vagina, or urinary bladder if the toxin was introduced there.

To accelerate the elimination of the already absorbed toxin, forced diuresis is used. The method involves the administration of diuretics and electrolyte solutions. A mandatory condition is the elimination of hypovolemia using plasma-substituting fluids (e.g., dextran-based preparations or complex saline solutions containing potassium, calcium, and magnesium chlorides, as well as sodium bicarbonate and sodium chloride with povidone).

Pathogenetic and symptomatic treatment

The pathogenetic principle aims to disrupt key links in disease development and restore vital functions: normalization of respiration, cardiac activity, liver, and kidney function. A critical step is detoxification of biological fluids and correction of the acid-base balance (ABB).

Main methods of instrumental and surgical detoxification:

• Plasmapheresis: removal of about 1.5 liters of toxic plasma followed by replacement with saline solutions or fresh frozen plasma with normal pH.
• Hemosorption: blood perfusion through a detoxifier with a sorbent (e.g., activated charcoal).
• Hemodialysis: blood purification using an "artificial kidney" machine.
• Peritoneal dialysis.
• Blood exchange transfusion: transfusion of donor blood to the recipient. Indicated for massive hemolysis, methemoglobin formation under the action of chemicals, or prolonged decrease in cholinesterase activity.

Symptomatic therapy aims to eliminate reactions and processes that worsen the patient's condition. It relieves manifestations that additionally exhaust the body: nausea, headache, muscle pain (myalgia), as well as hyper- or hypotensive reactions.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Mechanisms of action of chelating agents in heavy metal poisoning
• Principles of forced diuresis and correction of hypovolemia
• Extracorporeal detoxification methods: hemosorption and hemodialysis
• Pharmacological antagonism using atropine and acetylcholine as an example
• Pathogenesis of acid-base balance (ABB) disorders in poisonings

Other topics in «Chapter 18. Drug Addiction. Substance Abuse. Poisoning»

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