Epinephrine

Epinephrine (Adrenalin)

Class: Sympathomimetic Agent
Actions:
  • α-adrenergic stimulation produces vasoconstriction (which can also reduce bleeding) and mydriasis.
  • β1-adrenergic stimulation produces positive inotropic and chronotropic effects.  Also enhances conductivity and irritability of myocardium.
  • β2-adrenergic stimulation produces bronchial relaxation and dilation reversing bronchospasms.
Indications:
  • Anaphylactic shock
  • Acute asthma attack
  • 1st or 2nd degree heart blocks
  • Cardiac arrest
  • Wide-angled Glaucoma
  • Topically to control bleeding (e.g., nasal hemostasis)
Pharmacokinetics:
  • Onset: 3-5 minutes (quick)
  • Peak: 20 minutes
  • Half-Life: 2 minutes (short acting)
  • Metabolism:  MAO & COMT in the adrenergic synapses
Adverse Effects:
  • Cardiac: hypertension, tachycardia, palpitations, angina, tachydysrhythmias
  • Neurological: restlessness, nervousness, anxiety, tremors, headache
  • Respiratory: pulmonary edema
  • Skin: necrosis from vasoconstriction

 

Signs of Toxicity:
  • Hypertensive crisis
  • Chest pain
  • Pulmonary edema
  • Lethal dysrhythmias
Contraindications:
  • Tachydysrhythmias (heart rate > 100/minute)
  • Narrow-angle glaucoma
  • Hemorrhagic, traumatic, or cardiogenic shock
  • Cerebral arteriosclerosis
  • Coronary insufficiency
  • 2nd stage of labor
  • Local anesthesia of fingers, toes, ears, nose, or genitalia
Dosages & Routes:
  • Intravenous: 1 mg (1:10,000) IVP for cardiac arrest or heart block or anaphylactic shock  (can also be given intraosseous or endotracheal)
  • IV Drip:  1 mg (1:1,000) in 500 ml NS or D5W beginning with 1 mcg/min infusion titrated to effect (2-10 mcg/min range)
  • Subcutaneous (SC):  adult 0.1 – 0.5 mg (1:1,000); child 0.01 mg/kg (1:1,000) for bronchospasms
  • Ophthalmic: 1-2 drops 0.25-2% solution
  • Inhalation: Aerosol 1 inhalation q 4 hr for bronchospasms
  • SC for local anesthetic: 0.001% (1:100,000) combined with local anesthetic
Nursing Implications:
  • 1:10,000 equals 1 mg/10 ml (for IV pushes or neonatal umbilicus line)
  • 1:1,000 equals 1  mg/1 ml (for SC or IM injections)
  • EpiPen® is an IM injectable with .3 mg dose for adults or a smaller .15 mg dose for children (33-66 pounds).  Instruct patients with hypersensitivity risks on how to administer the EpiPen®.  Patient should seek immediate help after using EpiPen® due to short life of  medication.
  • Epinephrine may exacerbate chest pain, hypertension, and tachydysrhythmias.
  • Contact lenses should be removed prior to instilling eye drops.
  • Patients should be monitored for heart rate, cardiac rhythm, and blood pressure frequently if an IV drip is to be infused.
  • Never interrupt an intravenous infusion of medication to administer an IVPB or other medication.
  • Extravasation of epinephrine may cause tissue necrosis to skin.  Therefore, monitor IV site every hour.  Have phentolamine (Regitine®) close to the bedside of the patient.
  • MAO inhibitors will counteract the effects of epinephrine.
  • β-adrenergic blocking agents will block the actions of epinephrine on the heart.

 

References:

American Heart Association. (2006). Handbook of Emergency Cardiac Care (p. 51). Salem, MA: AHA.

Dirks, J.L. (2010) Cardiovascular therapeutic management.  In L.D. Urden, K.M. Stacy, & M.E. Lough's (Eds.) Critical care nursing: Diagnosis and management (6th ed., pp. 546-547).  St. Louis: Mosby Elsevier.

Lehne, R.A. (2010). Pharmacology for nursing care (7th ed., pp. 149-161).  St. Louis: Saunders Elsevier.

Wilson, B.A., Shannon, M.T., Shields, K.M., & Stang, C.L. (2007).  Prentice Hall Nurse's Drug Guide 2007 (pp. 600-604).  Upper Saddle River, NJ: Pearson Prentice Hall.

 

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