Pharmacology Study Notes: Acetaminophen, Activated Charcoal, Albuterol, Aspirin, Dextrose, and Epinephrine

Acetaminophen (Tylenol)

• Class: Non-narcotic analgesic, antipyretic
• Action: Inhibits the enzyme cyclooxygenase. Increases pain threshold in the CNS.
• Indication: Pain, fever
• Contraindications: Hypersensitivity. Patients with liver disease, severe hepatic impairment
• Precautions: Patients with history of hepatic complications
• Side Effects: Dizziness, lethargy, GI distress, diarrhea, hepatic failure, renal failure, diaphoresis (minimal in therapeutic doses)
• Interactions: Chronic alcohol use can increase the liver toxicity of acetaminophen
• Dose & Route:
  • Adult: $325\text{--}650\,\text{mg}$ PO every $4\text{--}6\,\text{hours}$ MAX $1\,\text{g/dose}$
  • Adult ($>50\,\text{kg}$): $1\,\text{g}$ every $6\,\text{hours}$ IV
  • Adult ($<50\,\text{kg}$): $15\,\text{mg/kg}$ every $6\,\text{hours}$ IV
  • Pediatric: $10\text{--}15\,\text{mg/kg}$ PO every $4\text{--}6\,\text{hours}$
  • Pediatric ($2\text{--}12\,\text{yo}$): Same as adult IV
• Onset & Duration:
  • Onset: $15\text{--}30\,\text{minutes}$
  • Duration: $3\text{--}4\,\text{hours}$

Activated Charcoal (Actidose)

• Class: Absorbent
• Action: Binds with ingested toxins in the GI tract to prevent absorption
• Indications: Oral ingestion of toxins; most commonly pills of ingested toxins
• Contraindications: AMS or risk of aspiration, ingestion of corrosives, caustics or petroleum distillates
• Precautions: Not specified
• Side Effects: Black tarry stool, constipation, moderate to severe nausea and vomiting
• Interactions: Will inactivate other oral medications
• Dose & Route:
  • Form: Premixed slurry bottle
  • Adult & Pediatric: $1\,\text{g/kg}$ PO
• Onset & Duration:
  • Onset: Varies
  • Duration: Until digested in the GI tract

Albuterol (Proventil, Ventolin)

• Class: Sympathomimetic Bronchodilator
• Action: Selective B2 agonist that stimulates adrenergic beta 2 receptors of the SNS, causing smooth muscle relaxation in the bronchial tree (bronchodilation) and decreased airway resistance
• Indication: Bronchospasm in COPD/Asthma. Crush injury/hyperkalemia
• Contraindication: Hypersensitivity. Symptomatic tachydysrhythmias, pulmonary edema (if used as primary treatment). Synergistic with other sympathomimetics
• Precautions: Heart disease. ECG that shows cardiac ischemia, severe HTN, tachydysrhythmias
• Side Effects: Tachycardia, palpitations, wheezing, hypertension, anxiety, nervousness, tremors, nausea, vomiting, heartburn, arrhythmias, chest pain, headache, coughing
• Interactions: Tricyclic antidepressants may potentiate vasculature effects. Beta blockers are antagonistic. May potentiate hyperkalemia caused by diuretics
• Dose & Route:
  • Adult (Bronchospasm): $2.5\text{--}5.0\,\text{mg}$ nebulized
  • Adult (Crush injury/Hyperkalemia): $10\text{--}20\,\text{mg}$ nebulized
  • Pediatric: $2.5\,\text{mg}$ nebulized
• Onset & Duration:
  • Onset: $5\text{--}15\,\text{min}$
  • Peak: $30\,\text{min}$
  • Duration: $3\text{--}4\,\text{hours}$

Aspirin (Bayer)

• Class: Platelet inhibitor (anti platelet aggregate), NSAID
• Action: Inhibits platelet aggregation causing prostoglandin inhibition (thromboxane A2)
• Indication: New onset chest pain suggestive of acute MI. Signs and symptoms suggestive of recent CVA
• Contraindication: Hypersensitivity. Acute asthma, GI bleeding ulcers. Administered to children or adolescents with suspected viral illness (Reyes Syndrome)
• Precautions: Hypersensitivity to other NSAIDs, fragile asthmatics, hepatic/renal impairment
• Side Effects: Heartburn, GI bleeding, prolonged bleeding, nausea, vomiting, bronchoconstriction in allergic patients
• Interactions: Patients allergic to NSAIDs. Seasonal allergies, liver disease, alcohol abuse, kidney disease, or coagulopathies
• Dose & Route:
  • Adult: $160\text{--}325\,\text{mg}$ PO
• Onset & Duration:
  • Onset: $15\text{--}20\,\text{minutes}$
  • Duration: $24\,\text{hours}$

Dextrose (D50, D25, D10)

• Class: Carbohydrate, hypertonic solution
• Action: Increases serum glucose levels. Short-term osmotic diuresis
• Indication: Hypoglycemia
• Contraindications: None in the presence of Hypoglycemia
• Precautions: Acute stroke, intracranial hemorrhage, brain injury. Cause severe tissue necrosis with IV infiltration
• Side Effects: Warmth, pain, burning, thrombophlebitis, rhabdomyolysis. Hyperglycemia (short lived)
• Interactions: None in the emergency setting
• Dose & Route:
  • D50: Prefilled syringe of $25\,\text{g} / 50\,\text{ml}$
  • D25: $12.5\,\text{g} / 50\,\text{ml}$ or $25\,\text{g} / 100\,\text{ml}$
  • D10: $25\,\text{g} / 500\,\text{ml}$
  • Adult: $25\,\text{g}$ slow IV; repeated as necessary
  • Pediatric: $0.5\,\text{g/kg/dose}$ slow IV; repeated as necessary
• Onset & Duration:
  • Onset: $30\text{--}60\,\text{seconds}$
  • Peak: Variable
  • Duration: Depends on severity of Hypoglycemia

Epinephrine 1:1,000 (Adrenaline)

• Class: Sympathomimetic
• Action: Bronchial dilation. Direct acting alpha & beta agonist
  • Alpha: Vasoconstriction
  • Beta 1: Positive Inotropic Effect (strength of contraction) INTENSITY; Chronotropic Effect (heart rate) CLOCK; Dromptropic Effect (electrical impulse) CONDUCTION
  • Beta 2: Bronchial smooth muscle relaxation & dilation of skeletal vasculature
• Indication: Acute anaphylaxis (allergic reaction with airway involvement)
• Contraindication: No contraindications in emergency situation
• Precautions: Patients with underlying cardiac conditions. Increases myocardial oxygen demand, may increase myocardial ischemia
• Side Effects: Hypertension, tachycardia, arrhythmias, pulmonary edema, anxiety, restlessness, psychomotor agitation, nausea, headache, angina
• Interactions: Potentiates other sympathomimetic/antidepressants. Deactivated by alkaline solutions (sodium bicarbonate). Monoamine oxidase inhibitors (MAOIs) may potentiate effects. Beta blockers may blunt effects
• Dose & Route:
  • Form: Prefilled autoinjectors, $1\,\text{mg/ml}$ vials or ampules
  • Adult: $0.3\text{--}0.5\,\text{mg}$ IM/SC PRN every $15\,\text{min}$
  • Pediatric: $0.01\,\text{mg/kg}$ up to $0.3\,\text{mg}$ IM
• Onset & Duration:
  • Onset: Immediate
  • Duration: $3\text{--}5\,\text{min}$

Epinephrine 1:10,000 (Adrenaline)

• Class: Sympathomimetic
• Action: Bronchial dilation. Direct acting alpha & beta agonist
  • Alpha: Vasoconstriction
  • Beta 1: Positive Inotropic Effect (strength of contraction) INTENSITY; Chronotropic Effect (heart rate) CLOCK; Dromptropic Effect (electrical impulse) CONDUCTION
  • Beta 2: Bronchial smooth muscle relaxation & dilation of skeletal vasculature
• Indications: Cardiac arrest; pulseless VTACH, VFIB, PEA, Asystole. Symptomatic bradycardia
• Contraindications:
  • Cardiac Arrest: None in the emergency setting
  • Symptomatic Bradycardia: Tachyarrhythmias, pulmonary edema, hypertension, myocardial ischemia, Hypovolemic shock, hypothermia
• Precautions: Increases myocardial oxygen demand; may potentially increase myocardial ischemia, patients with underlying cardiovascular disease
• Side Effects: Symptomatic Bradycardia: HTN. Tachycardia, arrhythmias, pulmonary edema, anxiety restlessness
• Interactions: Potentiates other sympathomimetic. Deactivated by sodium bicarbonate
• Dose & Route:
  • Adult Cardiac Arrest: $1\,\text{mg}$ $1:10,000$ IV every $3\text{--}5\,\text{min}$
  • Adult Symptomatic Bradycardia: $2\text{--}10\,\text{mcg/min}$ or $0.1\text{--}0.5\,\text{mcg/kg/min}$ (mix $1\,\text{mg}$ for every $100\,\text{ml}$)
  • Pediatric Cardiac Arrest: $0.01\,\text{mg/kg}$ IV every $3\text{--}5\,\text{min}$
  • Pediatric Symptomatic Bradycardia: $0.01\,\text{mg/kg}$ IV every $3\text{--}5\,\text{min}$
• Onset & Duration:
  • Onset: Immediate
  • Duration: $3\text{--}5\,\text{min}$
• Push Dose Mix (Epi 1:10,000 Procedure):
  • Discard $1\,\text{ml}$ of NS in $10\,\text{ml}$ Syringe = $9\,\text{ml}$ NS in syringe
  • Draw up $1\,\text{ml}$ of Epi $1:10,000$ = $0.1\,\text{mg} / 100\,\text{mcg}$
  • Syringe now contains $10\,\text{ml}$ of Epi at $10\,\text{mcg/ml}$ ($1:100,000$)
  • Dose: $0.5\text{--}2\,\text{ml}$ ($5\text{--}20\,\text{mcg}$) every $1\text{--}5\,\text{min}$