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Uploaded byDivya Rajput
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Elimination Enhancement clinical toxicology

Overview of medical interventions like forced diuresis and extracorporeal methods to accelerate toxin removal, reduce toxicity duration, and improve outcomes in poisoning cases.

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MS. DIVYA RAJPUT ASSISTANT PROFESSOR DEPARTMENT OF PHARMACOLOGY
Elimination Enhancement in Clinical Toxicology : Elimination enhancement (also called enhanced elimination) is the use of specific medical interventions to increase the removal of a poison or toxin from the body after it has been absorbed into the bloodstream. It is used in selected cases of poisoning to reduce the duration and severity of toxicity, especially when supportive care alone is insufficient. Elimination enhancement is the deliberate use of pharmacological or extracorporeal techniques to accelerate the elimination of toxic substances from the body, thereby reducing toxin concentration, limiting organ damage, and improving patient outcomes.
Objectives of Elimination Enhancement The main aims are to: Remove the poison from the bloodstream as quickly as possible. Shorten the duration of toxic effects. Prevent complications such as organ failure. Reduce mortality in severe poisoning. Decrease the need for prolonged intensive care.
"The various methods of eliminating absorbed poisons from the body" Introduction Once a poison has been absorbed, the body's natural elimination through the kidneys, liver, lungs, and gastrointestinal tract may be too slow. If the poison continues circulating in the blood, it can cause severe toxicity and organ damage. Therefore, elimination enhancement techniques are used to: •Reduce the concentration of poison in the blood. •Shorten the duration of poisoning. •Prevent permanent organ damage. •Improve survival in severe intoxication.
1. Forced Diuresis Forced diuresis is the deliberate increase in urine production by administering large amounts of intravenous fluids, sometimes combined with diuretics, to increase the renal excretion of certain poisons. Principle The kidneys remove many drugs from the blood. If urine production increases: ➡ More blood passes through the kidneys. ➡ More poison is filtered. ➡ Greater amount of poison is eliminated in urine.
Mechanism Normally Blood → Kidney → Small amount of toxin removed → Urine During forced diuresis Blood → Kidney → Increased urine flow → More toxin removed → Large urine output How is it done? The patient receives Intravenous normal saline Sometimes mannitol Sometimes furosemide (rarely used now) Urine output is carefully monitored. Target urine output 3–6 mL/kg/hour
2. Extracorporeal Techniques "Extracorporeal" means outside the body. These methods remove blood from the patient, eliminate the poison using a machine or filter, and return the purified blood to the body. Blood → Machine → Poison removed → Clean blood returned These methods are used only in life-threatening poisoning.
A. Haemodialysis Blood passes through a dialysis machine containing a semipermeable membrane. The poison diffuses from blood into dialysis fluid. Mechanism Blood → Dialysis membrane → Poison diffuses into dialysate → Clean blood returns Best for Poisons that are Water soluble Low molecular weight Low protein binding Low volume of distribution Ex: Lithium, Valproic Acid, Methanol, Salicylates
B. Hemoperfusion Blood passes through a cartridge filled with activated charcoal or resin. Instead of diffusion, toxins adsorb onto the charcoal surface. Mechanism Blood → Charcoal cartridge → Poison sticks to charcoal → Clean blood returns Best for Protein-bound drugs such as Carbamazepine Phenobarbital Theophylline
Advantages Removes toxins that dialysis cannot remove effectively. Complications Thrombocytopenia Hypocalcemia Hypoglycemia C. Peritoneal Dialysis The peritoneum (lining of the abdominal cavity) acts as the dialysis membrane. Dialysis fluid is introduced into the abdomen. Toxins diffuse from blood vessels into the fluid, which is then drained. Mechanism Blood vessels → Peritoneal membrane → Dialysis fluid → Removed
D. Hemofiltration Blood is passed through a highly permeable membrane. Instead of diffusion, toxins are removed mainly by convection (solvent drag), where water and dissolved solutes are filtered together. Used in Intensive Care Unit (ICU) Patients with kidney failure Hemodynamically unstable patients Continuous renal replacement therapy (CRRT) Advantages Gentle and continuous removal Better tolerated by unstable patients Disadvantages Slower toxin clearance than intermittent hemodialysis
E. Plasmapheresis The plasma (liquid part of blood) is separated and removed, then replaced with donor plasma or albumin. Mechanism Blood → Plasma separated → Plasma removed → New plasma added → Blood returned Uses Useful when toxins are Highly protein bound Located mainly in plasma Examples include Amanita mushroom toxins (selected cases) Certain autoimmune disorders (more common indication) Advantages Removes toxins attached to plasma proteins.
F. Plasma Perfusion Instead of whole blood, only the plasma is passed through an adsorbent column to remove toxins. Mechanism Blood → Plasma separated → Plasma through adsorbent → Clean plasma returned Uses Rarely used; reserved for selected poisonings involving large plasma-bound toxins. G. Cardiopulmonary Bypass (CPB) A heart–lung machine temporarily takes over the function of the heart and lungs.
The principle of ionization and ion trapping, which is the basis for enhancing renal elimination of drugs in poisoning (clinical toxicology). Understanding this concept helps explain why urinary alkalinization is used for acidic drug poisoning and urinary acidification (rarely used today) was once considered for basic drug poisoning. Principle: Ionization of Drugs Drugs exist in two forms: Non-ionized (Unionized) form Ionized form The proportion of these two forms depends on: pKa of the drug pH of the surrounding environment (urine, plasma, stomach, etc.) The relationship is described by the Henderson–Hasselbalch equation.
50% HA (non-ionized) 50% A⁻ (ionized) Both forms are present equally. Non-ionized molecules: have no electrical charge dissolve well in lipids diffuse easily through membranes Therefore they can move: from urine back into blood from blood into tissues across intestinal membranes across the blood-brain barrier Example A weak acid in its non-ionized form HA can easily diffuse through the renal tubular membrane. Therefore it is reabsorbed back into blood.
Ionized molecules carry a positive or negative charge dissolve well in water do not dissolve well in lipids Therefore they cannot easily cross cell membranes. Only the non-ionized form of a drug can easily cross biological membranes because it is lipid soluble. The ionized form remains in the aqueous fluid and crosses membranes poorly. This principle is called passive diffusion.
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology
Elimination Enhancement clinical toxicology