Focus on Pharmacology Essentials for Health Professionals Jahangir Moini, MD, MPH Chapter 28 Toxicology

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

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

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 heavy metal and corrosive chemical poisoning

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, seizures, cerebral edema, coma, death; 12–14 hours: tachypnea, cyanosis, tachycardia, pulmonary edema, pneumonitis Treatment: gastric lavage within 30 minutes; 10% solution of ethanol; and 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 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 depressants occur 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: 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

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

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

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: reducevenom absorption; incision and suction; ice should not be applied to bite