Epinephrine Flashcards
What is Epinephrine’s Mechanism of Action?
Epinephrine is a catecholamine, meaning it is a neurotransmitter that plays a large role in the regulation of the central nervous system. Will act as a strong alpha agonist, a strong beta-1 agonist, and moderate beta-2 agonist.
Alpha agonization will lead to systemic vasocontriction with increased peripheral vascular resistance, meaning the distal areas of the body will have a more difficult time supplying blood as they are constricted.
Beta 1 stimulation results in an increase in heart rate as well as myocardial contractility, output, and oxygen demand. Beta 2 stimulation results in bronchial smooth muscle relaxation as well as relaxation of smooth muscle in uterine, stomach, and intestines.
What is Epinephrine’s Class?
Alpha/beta adrenergic agonist, sympathomimetic
When is Epinephrine Indicated, and When is it Contraindicated?
Indicated: Cardiac arrest, bradycardia, shock, anaphylaxis, severe refractory wheezing (IM), croup/ bronchiolitis (nebulized)
Contraindicated: Coronary insufficiency, cardiac dilation.
Relatively Contraindicated: Uncontrolled hypertension, hypothermia, pulmonary edema, myocardial ischemia, hypovolemic shock.
What are the Potential Side Effects and Drug Interactions with Epi?
Side Effects: Nervousness, restlessness, headahce, tremor, dysrhythmias, chest pain, increased oxygen demand, hypertension, palpitations, nausea and vomiting.
Interactions: Will potentiate (increase effect) of sympathiomimetics, will be deactivated by alkaline solutions. MAOIs and antidepressants may potentiate effects, beta blockers may blunt effects.
Epinephrine Dosage for Anaphylaxis?
Adult and Pediatric
Adult: Give 0.3 mg IM in the anterolateral thigh. May give 1 mg/mL from a vial or autoinjector. May repeat every 5-15 minutes.
If patient has respiratory distress with wheezing, consider giving nebulized albuterol and/or 5 mL of 1mg/mL epi nebulized. If stridor present, consider same dose as above.
If signs of cardiovascular collapse apparent despite repeat IM doses, consider IV infusion at 0.5 mcg/kg/min with at least 60 mL/kg isotonic fluid bolus.
Pediatric: If weight less than 25 kg: Give 0.15 mg via IM to anterolateral thigh, if weight more than 25 kg, give 0.3 mg. May repeat doses. If respiratory distress with wheezing noted, consider nebulized albuterol and/or 5 mL of 1 mg/mL epi nebulized. Stridor consider 5 mL of 1 mg/mL epi nebulized.
If cardiovascular collapse assessed, consider 0.5 mcg/kg/min IV infusion with at least 60 mL/kg isotonic fluid bolus.
Epinephrine Dosage for an Adult with Severe Bronchoconstriction with Impending Respiratory Failure?
Give 0.01 mg/kg of 1 mg/mL IM; max dose 0.3 mg.
Should only give as adjunct therapy when there are no signs of clinical improvement!
Dosage for Profound Bradycardia with Signs of Hemodynamic Instability?
Adult: 0.02-0.2 mcg/kg/min tirated to mean arterial pressure greater than 65. Or IV/IO push doses of 10-20 mcg boluses (1-2mL) every 2 minutes.
Peds: IV/IO push dose 0.01 mg/kg (0.1 mL/kg) every 3-5 minutes
Dosage for Cardiac Arrest
1mg (0.1 mg/mL) IV/IO every 3-5 minutes during resucitation efforts. Follow each dose with a 20 mL flush, elevate arm 10-20 seconds after dosing
Peds: Give 0.01 mg/kg (0.1 mg/mL) IV/IO every 3-5 minutes during arrest. Max single dose: 1mg
Duration of Action
Onset: Less than 2 min IV, 3-10 minutes IM. Peak: Less than 5 min IV, 20 minutes IM. Duration: 5-10 minutes IV, 20-30 min IM.
