focus on 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


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

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PreventionPrevention

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


Figure 10-2 Child-resistant packaging.


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


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


Treatment of PoisoningTreatment 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: AcetaminophenSpecific Poisons: Acetaminophen

• Acetaminophen (Tylenol): nausea and vomiting (early stages); liver injury after 2–3 days

• Antidote: acetylcysteine given within 8–10 hours


Specific Poisons: AlcoholsSpecific Poisons: Alcohols

• Ethanol or ethyl alcohol• Treatment includes:

– Emesis, gastric lavage– Hemodialysis


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


Specific Poisons: Ethylene GlycolSpecific Poisons: Ethylene Glycol

• Treatment: gastric lavage within 30 minutes; 10% solution of ethanol; and hemodialysis


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


Specific Poison: MethanolSpecific Poison: Methanol

• Treatment: gastric lavage, IV administration of 10% solution of ethanol; hemodialysis


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


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


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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Specific Poison: AntihistaminesSpecific Poison: Antihistamines

• Signs/symptoms: CNS excitement or depression; drowsiness, stupor, coma

• Supportive treatment, phenobarbital or diazepam to control convulsions


Specific Poison: BenzodiazepinesSpecific Poison: Benzodiazepines

• Signs/symptoms: CNS depression occurs within 30 minutes; coma, respiratory depression

• Treatment: activated charcoal, respiratory support


Specific Poison: BleachesSpecific Poison: Bleaches

• Signs/symptoms: corrosive action in mouth, pharynx, esophagus

• Treatment: dilute ingested bleach with milk or water


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)


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


Specific Poison: CyanideSpecific Poison: Cyanide

• Medical emergency• Signs/symptoms: odor of bitter almonds• Treatment: nitrite to produce

methemoglobin; supportive measures such as 100% oxygen


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


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


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


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


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


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


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


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


Specific Poison: Specific Poison: OrganophosphatesOrganophosphates

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


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


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


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


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

focus on pharmacology essentials for health professionals chapter toxicology 10

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