Specific (Antidotal) Therapy
This type of treatment is most effective in the early stages of acute poisoning. The primary condition for its initiation is a definitively identified toxin. The mechanisms of action of antidotes vary depending on the nature of the poison:
- Gastrointestinal binding: achieved by administering enterosorbents directly into the stomach.
- Inactivation in internal media (chelation): formation of safe, soluble complexes with heavy metals for subsequent urinary excretion. Agents used include sodium dimercaptopropanesulfonate, calcium disodium edetate, and penicillamine.
- Inhibition of metabolism: preventing the formation of toxic metabolites in the liver. A classic example is the use of ethanol in methanol or ethylene glycol poisoning.
- Enzyme reactivation: restoring the activity of blocked enzyme systems (e.g., using cholinesterase reactivators in organophosphate poisoning).
- Pharmacological antagonism: competitive interaction at the receptor level (e.g., atropine vs. acetylcholine, neostigmine methylsulfate).
- Neutralization of animal venoms: reducing toxic effects through the administration of specific antivenoms.
Prevention of Absorption and Enhanced Elimination
To minimize the entry of poison into the systemic circulation, the routes of exposure must be cleared as rapidly as possible. In the pre-hospital setting, nasogastric gastric lavage is critically important. Additional measures include:
- Emesis induction: mechanical stimulation of the posterior pharyngeal wall or administration of emetics (e.g., apomorphine).
- Bowel decontamination: trapping and eliminating toxins using adsorbents and laxatives. Intestinal lavage with balanced solutions is effective to correct electrolyte imbalances and pH shifts.
- Removal from skin and cavities: thorough washing of the skin and mucous membranes with water, as well as irrigation of the rectum, vagina, or urinary bladder if the toxin was introduced via those routes.
To accelerate the elimination of already absorbed toxins, forced diuresis is employed. This method involves the administration of diuretics and electrolyte solutions. A mandatory prerequisite is the correction of hypovolemia using plasma expanders (e.g., dextran-based preparations or complex electrolyte solutions containing potassium, calcium, and magnesium chlorides, alongside sodium bicarbonate and sodium chloride with povidone).
Pathogenetic and Symptomatic Treatment
Pathogenetic therapy aims to interrupt key steps in the disease progression and restore vital functions: respiration, cardiac output, and hepatic and renal function. A crucial step is biological fluid detoxification and correction of acid-base status.
Key extracorporeal and surgical detoxification methods include:
- Plasmapheresis: removal of approximately 1.5 liters of toxic plasma followed by replacement with saline solutions or fresh frozen plasma with normal pH.
- Hemosorption: perfusion of blood through a detoxifier containing a sorbent (e.g., activated charcoal).
- Hemodialysis: blood purification using an artificial kidney machine.
- **Peritoneal dialysis.
- Exchange transfusion: replacement of the recipient's blood with donor blood. Indicated for massive hemolysis, methemoglobinemia caused by chemical agents, or prolonged depression of cholinesterase activity.
Symptomatic therapy targets reactions and processes that exacerbate the patient's condition. It alleviates distressing manifestations such as nausea, headache, myalgia, and hypo- or hypertensive crises.