Focus on Focus on PHARMACOLOGY PHARMACOLOGY ESSENTIALS FOR HEALTH PROFESSIONALS CHAPTER Toxicology 10
Focus onFocus on
PHARMACOLOGYPHARMACOLOGYESSENTIALS FOR HEALTH PROFESSIONALS
CHAPTER
Toxicology
10
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
ToxicologyToxicology
• 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Figure 10-1 In the majority of accidental childhood poisonings, poisonous materials are left in easy reach of children.
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Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
PreventionPrevention
• Child-resistant packaging• Poison Control Centers• Medication error prevention• Safe storage of toxins in home
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Figure 10-2 Child-resistant packaging.
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Poison DetectionPoison 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Treatment of PoisoningTreatment 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Treatment of PoisoningTreatment of Poisoning
• Cathartic agents: shorten transit time of chemicals through GI tract; work by retaining water in bowel to stimulate peristalsis
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Table 10-1 Poisons and Antidotes
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poisons: AcetaminophenSpecific Poisons: Acetaminophen
• Acetaminophen (Tylenol): nausea and vomiting (early stages); liver injury after 2–3 days
• Antidote: acetylcysteine given within 8–10 hours
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poisons: AlcoholsSpecific Poisons: Alcohols
• Ethanol or ethyl alcohol• Treatment includes:
– Emesis, gastric lavage– Hemodialysis
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poisons: Ethylene GlycolSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poisons: Ethylene GlycolSpecific Poisons: Ethylene Glycol
• Treatment: gastric lavage within 30 minutes; 10% solution of ethanol; and hemodialysis
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: MethanolSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: MethanolSpecific Poison: Methanol
• Treatment: gastric lavage, IV administration of 10% solution of ethanol; hemodialysis
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Specific Poison:Specific Poison:Heparin and WarfarinHeparin 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poisons: AmphetaminesSpecific Poisons: Amphetamines
• Methamphetamine most common; also pseudoephedrine, ephedrine
• Signs/symptoms: agitation, restlessness, acute psychosis, hypertension, tachycardia, brain damage, renal failure
• No specific treatment
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Mechanism of Action Mechanism of Action of Cocaine Animationof Cocaine Animation
Click on the screenshot to view an animation showing the mechanism of action of cocaine.
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Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: AntihistaminesSpecific Poison: Antihistamines
• Signs/symptoms: CNS excitement or depression; drowsiness, stupor, coma
• Supportive treatment, phenobarbital or diazepam to control convulsions
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: BenzodiazepinesSpecific Poison: Benzodiazepines
• Signs/symptoms: CNS depression occurs within 30 minutes; coma, respiratory depression
• Treatment: activated charcoal, respiratory support
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: BleachesSpecific Poison: Bleaches
• Signs/symptoms: corrosive action in mouth, pharynx, esophagus
• Treatment: dilute ingested bleach with milk or water
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Specific Poison: Carbon MonoxideSpecific 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)
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Specific Poison: CorrosivesSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: CyanideSpecific Poison: Cyanide
• Medical emergency• Signs/symptoms: odor of bitter almonds• Treatment: nitrite to produce
methemoglobin; supportive measures such as 100% oxygen
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: DigoxinSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Electrolyte ImbalancesElectrolyte 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: Isoniazid (INH)Specific Poison: Isoniazid (INH)
• Signs/symptoms: fever, peripheral neuritis, jaundice, skin rash, hepatic injury
• Treatment: pyridoxine, gastric lavage, activated charcoal, sodium bicarbonate, hemodialysis
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Specific Poison: LeadSpecific Poison: Lead
• Signs/symptoms: metallic taste, abdominal pain, vomiting, CNS depression, respiratory failure
• Treatment: chelating agents, IV EDTA and dimercaprol, gastric lavage
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: LithiumSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: MercurySpecific 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
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Specific Poison: OpioidsSpecific Poison: Opioids
• Signs/symptoms: euphoria, drowsiness, constricted pupils, hypotension, bradycardia, hypothermia, coma, respiratory arrest
• Treatment: gastric lavage or emesis, activated charcoal, naloxone
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: Specific Poison: OrganophosphatesOrganophosphates
• Signs/symptoms (30 minutes–2 hours): nausea, vomiting, urinary and fecal incontinence, abdominal cramps, increased bronchial secretions, wheezing, coughing, salivation, sweating, blurred vision
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: Specific Poison: OrganophosphatesOrganophosphates
• Treatment: remove clothing, wash skin with soap and water; activated charcoal; supportive measures: treatment of seizures, ventilatory assistance, oxygen
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: Specific Poison: Petroleum DistillatesPetroleum Distillates
• Signs/symptoms: pulmonary edema, pneumonitis, resembles alcohol intoxication, nausea, headache, burning sensation in chest
• Treatment: emesis (if alert), oxygen therapy
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: SalicylatesSpecific 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
Focus on Pharmacology: Essentials for Health Professionals, Second EditionJahangir Moini
Specific Poison: TheophyllineSpecific 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
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Bites and StingsBites 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