Gut Deccontamination clinical toxicology

Gut Deccontamination clinical toxicology

• 1.
  MS. DIVYA RAJPUT ASSISTANTPROFESSOR DEPARTMENT OF PHARMACOLOGY A-ONE PHARMACY COLLEGE
• 4.
  Emesis (Induced Vomiting) Definition: Emesisis the artificial induction of vomiting to remove poison from the stomach before it gets absorbed into the bloodstream. Why is emesis restricted? The heading says: "Emesis is heavily restricted and relies exclusively on Syrup of Ipecac." This means that emesis is no longer routinely recommended in modern toxicology because: •It is not effective for most poisonings. •It may delay more effective treatments such as activated charcoal. •Vomiting increases the risk of aspiration (vomit entering the lungs), which can cause aspiration pneumonia. •Many poisons are already absorbed by the time vomiting occurs. Therefore, routine use of emesis is discouraged.
• 5.
  Strict efficacy window(Green Timeline) The timeline shows: 0–6 hours •Emesis is only useful during the first 4–6 hours after ingestion. •It works best in: • Conscious patients • Alert patients • Cooperative patients After this period: •Most poison has moved into the intestine. •Vomiting removes very little poison.
• 6.
  Syrup of Ipecac theCephaelis ipecacuanha plant. Syrup of Ipecac contains two active alkaloids: •Cephaeline •Emetine These chemicals stimulate vomiting. Mechanism of action A. Peripheral mechanism (Stomach) Ipecac irritates the stomach lining. ↓ Stimulates gastrointestinal sensory receptors. ↓ Signals are sent to the brain. ↓ Vomiting occurs.
• 7.
  B. Central mechanism(Brain) Ipecac also stimulates the: Chemoreceptor Trigger Zone (CTZ) ↓ Activates the vomiting center in the medulla. ↓ Produces vomiting. So, Ipecac acts by both peripheral (gastric irritation) and central (CTZ stimulation) mechanisms.
• 9.
  Do NOT inducevomiting if the patient has a compromised airway or has ingested a corrosive substance. This is because vomiting may cause aspiration (poison entering the lungs), airway obstruction, or further injury to the esophagus and stomach. Types of Contraindications contraindications into Relative and Absolute (Obsolete). 1. Relative Contraindications These are situations where inducing vomiting is generally avoided, but the decision depends on the poison, amount ingested, and clinical condition. A. Infants (<1 year) and Elderly Patients Reason Weak cough and gag reflex Higher risk of aspiration pneumonia Unable to protect their airway Clinical significance Vomiting can cause stomach contents to enter the lungs.
• 10.
  B. Pregnancy Reason •Vomiting increasesintra-abdominal pressure. •Can cause maternal dehydration. •Severe vomiting may reduce uteroplacental blood flow. Clinical significance Risk to both mother and fetus. C. Heart Disease or Cardiotoxic Poisoning Examples: Digoxin Tricyclic antidepressants Cocaine Reason Vomiting stimulates the vagus nerve and causes stress. This may produce: Arrhythmias Bradycardia Cardiac arrest in severe poisoning
• 11.
  D. Bleeding Disorders(Bleeding Diathesis) Examples: •Hemophilia •Thrombocytopenia •Patients on anticoagulants Reason Forceful vomiting can cause: •Esophageal tears •Gastric bleeding •Hematemesis E. Time Since Poisoning >6–8 Hours Reason After 6–8 hours, most poison has already moved from the stomach into the intestine. Therefore, Vomiting removes very little poison. Risks outweigh benefits.
• 12.
  2. Absolute (Obsolete)Contraindications These are conditions where vomiting should NEVER be induced. A. Coma or Impaired Gag Reflex Examples: Unconscious patient Severe alcohol intoxication Sedative overdose Reason The patient cannot protect the airway. If vomiting occurs: → Stomach contents enter the lungs → Aspiration pneumonia → Respiratory failure → Death This is one of the most important contraindications. B. Convulsant Poisons Examples: Strychnine Isoniazid (INH) Theophylline Camphor Reason These poisons can produce sudden seizures. During a seizure, Patient cannot swallow. Vomit easily enters the lungs.
• 13.
  C. Corrosive Ingestionor Sharp Objects Examples of corrosives: •Acids (HCl, sulfuric acid) •Alkalis (bleach, sodium hydroxide) Examples of sharp objects: •Pins •Glass •Razor blades Reason Vomiting brings the corrosive substance back through the esophagus, causing a second burn. For sharp objects, •They may cut or perforate the esophagus or stomach. Therefore, vomiting is contraindicated.
• 14.
  D. Petroleum Distillatesor CNS Depressants Petroleum Distillates Examples: •Kerosene •Petrol •Diesel •Paint thinner •Turpentine Reason These substances have low viscosity and high volatility, making them easy to aspirate into the lungs. Aspiration may cause: •Chemical pneumonitis •Severe respiratory distress
• 15.
  CNS Depressants Examples: •Opioids •Benzodiazepines •Tricyclic antidepressants Reason Thesedrugs depress consciousness and reduce the gag reflex. Vomiting greatly increases the risk of aspiration. E. Poisons that are Inherently Emetic Examples: Copper sulfate Zinc sulfate These substances already cause vomiting naturally. Reason Inducing additional vomiting offers no benefit and may worsen dehydration and electrolyte imbalance.
• 17.
  What is GastricLavage? Gastric lavage, commonly known as stomach washing or stomach pumping, is a medical procedure used to remove poisonous substances or drugs from the stomach after they have been swallowed. It is performed by inserting a large-bore tube (called an orogastric tube or nasogastric tube) through the mouth or nose into the stomach. Small amounts of warm saline or water are then introduced into the stomach and suctioned back repeatedly to wash out the stomach contents.
• 18.
  "Gastric Lavage isno longer routine; reserve it for acute, life-threatening ingestions.“ Earlier, gastric lavage was commonly performed for almost every poisoning case. However, studies by the American Academy of Clinical Toxicology (AACT) and the European Association of Poisons Centers and Clinical Toxicologists (EAPCCT) found that: There is no strong evidence that routine gastric lavage improves survival. It can cause serious complications, including aspiration pneumonia, oesophageal injury, gastric perforation, electrolyte imbalance, hypoxia, and even death. Therefore, it should only be performed in carefully selected patients. "No certain evidence that routine use improves outcomes. Significant morbidity and mortality risks are indisputable.“ Routine gastric lavage: ❌ Does not clearly reduce mortality ❌ Does not consistently improve patient recovery ✔️ Carries proven risks Hence, physicians should perform it only when the expected benefit is greater than the risk.
• 19.
  Post-Ingestion Window 1. Within1–2 Hours INDICATED Only for: Life-threatening poisoning Massive overdose Poison likely to remain in the stomach Patient presents within 1–2 hours
• 20.
  Most poisons remainin the stomach only for about 1 hour. After that, they move into the small intestine where lavage cannot remove them. Therefore lavage is useful only when performed early. Examples Massive ingestion of Tricyclic antidepressants Calcium channel blockers Beta blockers Colchicine Iron (selected cases) provided the airway is protected.
• 21.
  2. Between 6–12Hours Normally gastric lavage is NOT useful after several hours because most poison has already left the stomach. However, there are exceptions. Consider only for delayed gastric emptying, sustained-release preparations, gastric concretions, or specific agents. A. Delayed Gastric Emptying Some poisons slow stomach movement. Therefore poison remains inside longer. Examples: Opioids Anticholinergic drugs Since poison stays in the stomach, lavage may still help even after several hours.
• 22.
  B. Sustained-Release Preparations Thesetablets dissolve slowly. Examples: Extended-release tablets Controlled-release tablets Even after several hours, a significant amount of drug may still be inside the stomach. Example: Sustained-release verapamil Sustained-release theophylline
• 23.
  C. Gastric Concretions(Bezoars) Sometimes tablets stick together and form a large mass called a bezoar. This releases poison slowly over many hours. Examples: Aspirin tablets Iron tablets In these cases lavage may be considered.
• 24.
  3. Non-Toxic Agents DoNOT perform gastric lavage when: Poison is non-toxic Ingestion is harmless Someone wants to punish the patient Examples Small ingestion of: Vitamins Most cosmetics Toothpaste Mild soaps These patients do not benefit from lavage.
• 25.
  Why is GastricLavage No Longer Routine? Because it has many complications. Complications Aspiration Pneumonia Vomited gastric contents enter the lungs. This is the most common serious complication. Hypoxia Low oxygen occurs during the procedure. Laryngospasm Reflex closure of the vocal cords causing airway obstruction. Oesophageal Injury Insertion of the tube may tear the oesophagus. Gastric Perforation Rare but life-threatening complication. Electrolyte Disturbances Repeated saline irrigation may alter electrolyte balance. Arrhythmias Vagal stimulation during tube insertion may cause bradycardia or other rhythm disturbances.
• 26.
  Airway Protection Before performinggastric lavage: •Assess consciousness. •If the patient has a decreased level of consciousness (GCS < 8), endotracheal intubation should be performed first to protect the airway and prevent aspiration. *Glasgow Coma Scale (GCS) The Glasgow Coma Scale (GCS) is a neurological scoring system used to assess a patient's level of consciousness, especially after head injury, poisoning, stroke, or coma. It evaluates three responses: 1.Eye Opening (E) 2.Verbal Response (V) 3.Motor Response (M)
• 30.
  Activated Charcoal Definition: Activated charcoalis a specially processed form of carbon with an extremely large surface area that adsorbs (binds onto its surface) many drugs and poisons in the gastrointestinal tract, preventing their absorption into the bloodstream. Important: Activated charcoal adsorbs toxins, not absorbs them. Adsorption: Molecules stick to the surface of charcoal. Absorption: Molecules enter inside a substance or tissue.
• 31.
  "Activated charcoal haltsabsorption through massive microscopic surface area" The key reason activated charcoal is effective is its enormous microscopic surface area. Although 1 gram of charcoal appears very small, under a microscope it contains millions of tiny pores. These pores provide thousands of binding sites where toxins become trapped. The poison remains attached to the charcoal instead of passing through the intestinal wall into the blood. The toxin-charcoal complex is then eliminated naturally in the feces.
• 32.
  Adsorption of toxins Activatedcharcoal works by physical adsorption. When poison reaches the stomach or intestine, ↓ Poison molecules stick to the charcoal surface through weak intermolecular forces (Van der Waals forces). ↓ The toxin cannot cross the intestinal wall. ↓ No systemic absorption occurs. ↓ The toxin is excreted in feces.
• 33.
  Why Activated CharcoalIs So Effective It has: •Huge surface area •Millions of microscopic pores •Strong adsorptive capacity •Acts rapidly •Not absorbed into blood •Eliminates poison safely through stool
• 35.
  Multiple-Dose Activated Charcoal(MDAC), which is a special method of giving activated charcoal repeatedly after poisoning. Unlike a single dose, MDAC is given several times to increase the elimination of certain drugs from the body. What is Multiple-Dose Activated Charcoal (MDAC)? Multiple-Dose Activated Charcoal (MDAC) is the repeated administration of activated charcoal at regular intervals after an overdose. Purpose Prevent further absorption of poison from the intestine. Remove drugs that are already absorbed into the bloodstream. Shorten the drug's half-life. Reduce the duration and severity of poisoning. MDAC works best for drugs that: Undergo enterohepatic circulation Undergo enteroenteric circulation Have a long half-life Are slowly absorbed Are released continuously from the GI tract
• 36.
  1. Theophylline Uses •Asthma •COPD Why MDAChelps: •Long half-life •Undergoes enteroenteric circulation •Serious overdose causes: • seizures • arrhythmias • vomiting MDAC significantly increases elimination. 2. Phenobarbitone (Phenobarbital) Uses Epilepsy Sedative Reason: Very long half-life (2–5 days) Large amount returns into intestine Benefits: Speeds elimination Reduces coma duration
• 37.
  3. Quinine Used for: Malaria Overdosecauses: Blindness Hearing loss Hypotension Arrhythmias MDAC increases clearance. 4. Digitoxin Used for: Heart failure Arrhythmias Digitoxin undergoes: Extensive enterohepatic circulation Repeated charcoal prevents reabsorption.
• 38.
  Advantages of MDAC Comparedwith a single dose of activated charcoal, MDAC: Enhances elimination of certain drugs. Reduces the drug's half-life. Lowers blood drug concentration more quickly. May reduce the need for extracorporeal treatments (such as dialysis) in selected poisonings. Can improve recovery in severe overdoses of susceptible drugs.
• 40.
  The role ofcatharsis (use of cathartics/laxatives) in gastrointestinal (GI) decontamination. Cathartics are medicines that increase bowel movements and help move intestinal contents out more quickly. In poisoning, they were once used to reduce the time a poison remains in the intestine. However, current evidence shows they have very limited benefit and are not routinely recommended.
• 41.
  What is Catharsis? Catharsisis the rapid emptying of the intestines by using laxatives (cathartics). Definition Catharsis is the process of purging the gastrointestinal tract by increasing intestinal motility and drawing water into the bowel so that intestinal contents are expelled quickly through the stool. Aim •Reduce the time poison stays in the intestine. •Decrease further absorption of poison. •Remove poison that has already reached the intestines.
• 42.
  MECHANISM OF ACTION Step1: Fluid enters the intestinal lumen (Osmotic retention) This as "fluid entering the lumen (osmotic retention)." What happens? Certain cathartics (such as sorbitol or magnesium sulfate) contain substances that cannot be easily absorbed by the intestine. Because of this: •Water moves from the blood into the intestine by osmosis. •The intestinal contents become softer and more liquid. •The bowel becomes distended (stretched). This increases the volume of intestinal contents.
• 43.
  Step 2: Stimulationof muscular walls (Motility reflex) This as "stimulated muscular walls (motility reflexes)." As the intestine stretches because of the extra water: •Stretch receptors in the intestinal wall are activated. •Smooth muscles begin rhythmic contractions (peristalsis). •The bowel contents move more rapidly toward the rectum. Step 3: Faster Transit Time The poison moves rapidly through the gastrointestinal tract. Instead of remaining in the intestine for several hours, it passes out in the stool more quickly. Therefore: Cathartic → Water enters intestine → Increased peristalsis → Faster bowel movement → Faster elimination of intestinal contents
• 44.
  Why Were CatharticsUsed in Poisoning? Earlier, doctors believed that if poison remained in the intestine for a shorter time, less of it would be absorbed. Cathartics were sometimes given: •Alone •With activated charcoal (especially sorbitol with the first charcoal dose) The idea was that the poison would be expelled before more absorption could occur.