10 Toxicology

Multimedia Directory Slide 19 Mechanism of Action of Cocaine Animation

Toxicology 10 million people are poisoned in U.S. each year. Attempted suicide Accidental legal drug overdosage Illegal drug overdosage Snake, spider bites Exposure to toxins in workplace

Cathy Melloan / PhotoEdit, Inc. Figure 10-1 In the majority of accidental childhood poisonings, poisonous materials are left in easy reach of children.

Prevention Child-resistant packaging Poison Control Centers Medication error prevention Safe storage of toxins in home

Figure 10-2 Child-resistant packaging.

Poison Detection Some poisons have specific symptoms to assist in giving an accurate diagnosis: Cyanide: unmistakable odor of bitter almonds Insecticides: GI hyperactivity, salivation, pupillary constriction Carbon monoxide: cherry-colored flush of skin and mucous membranes

Treatment of Poisoning Emetics (e.g., ipecac): trigger vomiting; contraindicated in ingestion of corrosives Absorbents (activated charcoal): bind poison molecules to charcoal and excreted; effective in cardiac glycoside and methylxanthine poisoning, heavy metal and corrosive chemical poisoning

Treatment of Poisoning Cathartic agents: shorten transit time of chemicals through GI tract; work by retaining water in bowel to stimulate peristalsis

Table 10-1 Poisons and Antidotes

Specific Poisons: Acetaminophen Acetaminophen (Tylenol): nausea and vomiting (early stages); liver injury after 2–3 days Antidote: acetylcysteine given within 8–10 hours

Specific Poisons: Alcohols Ethanol or ethyl alcohol Treatment includes: Emesis, gastric lavage Hemodialysis

Specific Poisons: Ethylene Glycol Antifreeze, windshield de-icing solutions Signs/symptoms: within 1–12 hours: nausea, vomiting, ataxia, seizures, cerebral edema, coma, death; 12–14 hours: tachypnea, cyanosis, tachycardia, pulmonary edema, pneumonitis

Specific Poisons: Ethylene Glycol Treatment: gastric lavage within 30 minutes; 10% solution of ethanol; and hemodialysis

Specific Poison: Methanol Wood alcohol; antifreeze, windshield-washer fluid, solvent in photocopier solutions Signs/symptoms: visual disturbances, bradycardia, seizures, metabolic acidosis, respiratory depression, coma; blindness, and permanent retinal damage

Specific Poison: Methanol Treatment: gastric lavage, IV administration of 10% solution of ethanol; hemodialysis

Specific Poison: Heparin and Warfarin Heparin signs/symptoms: hemorrhage, ecchymoses, melena Heparin treatment: slow IV infusion of protamine sulfate Warfarin signs/symptoms: hemorrhage Warfarin treatment: phytonadione (vitamin K); blood products with clotting factors

Specific Poisons: Amphetamines Methamphetamine most common; also pseudoephedrine, ephedrine Signs/symptoms: agitation, restlessness, acute psychosis, hypertension, tachycardia, brain damage, renal failure No specific treatment

Mechanism of Action of Cocaine Animation Click on the screenshot to view an animation showing the mechanism of action of cocaine. Back to Directory

Specific Poison: Antihistamines Signs/symptoms: CNS excitement or depression; drowsiness, stupor, coma Supportive treatment, phenobarbital or diazepam to control convulsions

Specific Poison: Benzodiazepines Signs/symptoms: CNS depression occurs within 30 minutes; coma, respiratory depression Treatment: activated charcoal, respiratory support

Specific Poison: Bleaches Signs/symptoms: corrosive action in mouth, pharynx, esophagus Treatment: dilute ingested bleach with milk or water

Specific Poison: Carbon Monoxide Signs/symptoms: cherry color in skin and mucous membranes, coma, death Treatment: pure oxygen, ventilation support, diuretics and steroids (to treat resultant cerebral edema)

Specific Poison: Corrosives Ingestion almost always with suicidal intent Signs/symptoms: irritation; severe pain; bleeding; severe burns in mouth, esophagus, stomach; profound shock Treatment: immediate dilution with water or milk; emesis or gastric lavage contraindicated

Specific Poison: Cyanide Medical emergency Signs/symptoms: odor of bitter almonds Treatment: nitrite to produce methemoglobin; supportive measures such as 100% oxygen

Specific Poison: Digoxin Signs/symptoms: anorexia, nausea, vomiting, lethargy, abdominal cramping, diarrhea, vertigo, fatigue, muscle weakness, blurred vision, seizures, diplopia, electrolyte imbalance, bradycardia Treatment: ipecac, activated charcoal, lavage

Electrolyte Imbalances Magnesium: treatment is IV of 10 mL of a 10% solution of calcium gluconate Potassium: treatment is calcium administration, sodium bicarbonate or glucose/insulin Iron: treatment is whole bowel irrigation, deferoxamine

Specific Poison: Isoniazid (INH) Signs/symptoms: fever, peripheral neuritis, jaundice, skin rash, hepatic injury Treatment: pyridoxine, gastric lavage, activated charcoal, sodium bicarbonate, hemodialysis

Specific Poison: Lead Signs/symptoms: metallic taste, abdominal pain, vomiting, CNS depression, respiratory failure Treatment: chelating agents, IV EDTA and dimercaprol, gastric lavage

Specific Poison: Lithium Signs/symptoms: tremor, diarrhea, polydipsia, anorexia, polyuria, vomiting, blurred vision, hypothyroidism, hyperglycemia, weight gain Treatment: gastric lavage within 1 hour, activated charcoal, whole bowel irrigation, sodium polystyrene sulfonate, volume resuscitation

Specific Poison: Mercury Signs/symptoms: burning sensation in throat, metallic taste, discoloration and edema of mouth, vomiting, bloody diarrhea, shock Treatment: gastric lavage, activated charcoal, IM dimercaprol

Specific Poison: Opioids Signs/symptoms: euphoria, drowsiness, constricted pupils, hypotension, bradycardia, hypothermia, coma, respiratory arrest Treatment: gastric lavage or emesis, activated charcoal, naloxone

Specific Poison: Organophosphates Signs/symptoms (30 minutes–2 hours): nausea, vomiting, urinary and fecal incontinence, abdominal cramps, increased bronchial secretions, wheezing, coughing, salivation, sweating, blurred vision

Specific Poison: Organophosphates Treatment: remove clothing, wash skin with soap and water; activated charcoal; supportive measures: treatment of seizures, ventilatory assistance, oxygen

Specific Poison: Petroleum Distillates Signs/symptoms: pulmonary edema, pneumonitis, resembles alcohol intoxication, nausea, headache, burning sensation in chest Treatment: emesis (if alert), oxygen therapy

Specific Poison: Salicylates Signs/symptoms: vertigo, hearing impairment, nausea, vomiting, diarrhea, sweating, drowsiness, fever, headache, convulsions, hallucinations, cardiovascular collapse, coma Treatment: emesis, gastric lavage, activated charcoal, osmotic cathartic, artificial ventilation

Specific Poison: Theophylline Signs/symptoms: hypokalemia, hyperglycemia, hypercalcemia, hypophosphatemia, acidosis; nausea, vomiting, abdominal pain, tachycardia; seizures, hypotension, dysrhythmias Treatment: endotracheal intubation and gastric lavage, activated charcoal, benzodiazepines and phenobarbital to treat seizures; hemoperfusion or hemodialysis

Bites and Stings Scorpion: treatment is antivenom, calcium gluconate, and phenobarbital Spiders: antivenom, IV calcium gluconate, antibiotics, tetanus immunization, oxygen, antihistamines, adrenalin, muscle relaxants Snake bites: reduce venom absorption; incision and suction; ice should not be applied to bite