Autonomic Nervous System Regulation
4.16 Alpha and Beta Receptor Agonists (Catecholamines)
Catecholamines
Epinephrine and norepinephrine (NE) are adrenergics that stimulate the beta and alpha receptors on the target cell. Dopamine has dose-dependent effects on targeted arteries in the kidneys, heart, and brain.
Epinephrine (Alpha and Beta Receptor Agonist): Epinephrine acts on both alpha- and beta-adrenergic receptors and is used in several routes including intravenously (IV), subcutaneously, intramuscularly, and via inhalation. Epinephrine decreases vasodilation and increases vascular permeability through its alpha-adrenergic receptor action, which can lead to loss of intravascular fluid volume and hypotension. Through its action on beta-adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation and helps alleviate bronchospasm, wheezing, and dyspnea that may occur during anaphylaxis.
Indications for Use: Epinephrine is used for severe allergic reactions (anaphylaxis), acute bronchospasm during asthma attacks, cardiac resuscitation, hypotension in severe shock, or for local injection to control superficial bleeding.
Nursing Considerations Across the Lifespan: Epinephrine is contraindicated for use in fingers, toes, ears, nose, or genitalia when used with local anaesthetic due to the vasoconstrictive action. Contraindicated in clients with narrow-angle glaucoma. Administer with caution to the elderly and those with pre-existing cardiovascular disease. When administering IV, monitor vitals (blood pressure, heart rate and respiratory rate) and cardiovascular and respiratory systems closely; if blood pressure increases sharply, give rapid-acting vasodilators. Monitor IV site for extravasation. Discard IV solution if discoloured.
Epinephrine can be used across the lifespan. It can also be given to pregnant women in the case of anaphylaxis.
Patient Teaching & Education with EpiPen: Epinephrine formulated in a pen for injection is known as EpiPen. EpiPen is used for severe allergic reactions after exposure to an allergen like a bee sting. Check expiration date, store at room temperature, and protect from light. Effects fade after 15-20 minutes, so seek medical care immediately.[1]
Norepinephrine is another catecholamine, and is used as a peripheral vasoconstrictor (due to alpha-adrenergic action) and as an inotropic stimulator of the heart and dilator of coronary arteries (due to beta-adrenergic action) in clients with critically low blood pressure.
Epinephrine and Norepinephrine Medication Card
Now let’s take a closer look at the medication card for epinephrine and norepinephrine.[2][3] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.
Medication Card 4.16.1: Epinephrine and Norepinephrine
Class: Catecholamine
Prototypes: Epinephrine and Norepinephrine
Therapeutic Effects
- treatment of anaphylaxis
- cardiac resuscitation
Administration
- IV, IM, SC
- Discard IV solution if discolored
- Contraindicated for use in fingers, toes, ears, nose, or genitalia when used with local anesthetic
Indications
- Reversal of severe allergic reaction, bronchodilation, increased blood pressure, cardiac resuscitation, or control of superficial bleeding
Side Effects
- hypertension
- tachycardia
Nursing Considerations
- Monitor vitals (blood pressure, heart rate, respiratory rate), cardiovascular and respiratory systems closely when administering IV
- If administering IV, monitor IV site for extravasation
Dopamine is another type of catecholamine specifically used to improve perfusion of organs, improve cardiac output, and increase blood pressure.
Mechanism of Action: In low doses, dopamine mainly stimulates dopamine receptors and dilates the renal vasculature. Moderate doses of dopamine stimulate beta receptors for a positive inotropic effect. Higher doses also stimulate alpha receptors, constricting blood vessels and increasing blood pressure.
Indications for Use: Dopamine is used to treat shock, improve perfusion to vital organs, increase cardiac output, and correct hypotension.
Nursing Considerations Across the Lifespan: During infusion, frequently monitor blood pressure, cardiac output, urine output, and colour and temperature of limbs. If urine flow decreases without hypotension, notify prescriber because dosage may need to be reduced. Concurrent alpha or beta-blockers can antagonize dopamine. Adverse effects include hypotension, tachycardia, palpitations, and decreased blood flow to the extremities.
Dopamine is safe to adminster to pediatric and older adults.
Patient Teaching & Education: Clients should contact their health care provider immediately if experiencing unusual sweating, dizziness, heart palpitations, or chest pain.
Dopamine Medication Card
Now let’s take a closer look at the medication card for dopamine.[4][5] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.
Medication Card 4.16.2: Dopamine
Class: Catecholamine
Prototypes: Dopamine
Therapeutic Effects
- increase CO and BP
Administration
- IV
- Must be administered via IV pump
Indications
- Hypotension or shock: Treatment of severe hypotension or shock (eg, septic shock and other vasodilatory shock states, cardiogenic shock, decompensated heart failure, post–cardiac arrest) that persists during and after adequate fluid volume replacement.
- Increased blood flow to kidneys causing increased urine output
- Increased cardiac output and elevated blood pressure
Side Effects
- Hypotension
- Tachycardia
- Palpitations
- Dyspnea
- Decreased blood flow to extremities
- If urine flow decreases without hypotension, notify prescriber because dosage may need to be reduced
Nursing Considerations
- During infusion, frequently monitor ECG, blood pressure, cardiac output, pulse rate, urine output, and color and temperature of limbs
- Check urine output often
- uCentral from Unbound Medicine. https://www.unboundmedicine.com/ucentral ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- UpToDate (2021). Epinephrine. https://www.uptodate.com/contents/search ↵
- This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain. ↵
- UpToDate (2021). Dopamine. https://www.uptodate.com/contents/search ↵
Include norepinephrine, epinephrine and dopamine. Stimulate the adrenergic receptors.