Adrenergic Agonist

Adrenergic agonists function by stimulating the sympathetic nervous system.
These agents mimic the action of the neurotransmitters norepinephrine and epinephrine.
They act directly on specific adrenergic receptor sites throughout the body, including:
- The heart.
- The bronchi.
- The gastrointestinal (GI) tract.
- The urinary bladder.
- The ciliary muscles of the eye.

Alpha 1 ( $\alpha_1$ ) Receptors:
- Increases cardiac contractility.
- Causes vasoconstriction.
- Dilates the pupils.
- Relaxes the bladder.
- Contracts the prostate.
Beta 1 ( $\beta_1$ ) Receptors:
- Increases cardiac contractility and heart rate.
- Increases renin secretion which results in increased blood pressure.
- Memory aid: Beta 1 affects "1 heart."
Beta 2 ( $\beta_2$ ) Receptors:
- Dilates the bronchioles.
- Promotes relaxation of the gastrointestinal tract and the uterus.
- Increases blood flow in skeletal muscles.
- Activates liver glycogenolysis, which subsequently increases blood sugar levels.
- Memory aid: Beta 2 affects "2 lungs."

Epinephrine is a nonselective sympathomimetic adrenergic agonist.
It stimulates alpha 1 ( $\alpha_1$ ), beta 1 ( $\beta_1$ ), and beta 2 ( $\beta_2$ ) receptors.
Mechanism of action involves activating the sympathetic nervous system:
- Stimulation of Alpha 1 increases blood pressure.
- Stimulation of Beta 1 increases the heart rate.
- Stimulation of Beta 2 promotes bronchodilation.

Contraindications:
- Tachycardia.
- Glaucoma.
- Labor.
Cautions for use in patients with:
- Hypertension.
- Prostatic hypertrophy.
- Diabetes mellitus.

MAOIs (Monoamine Oxidase Inhibitors) and tricyclic antidepressants: These can intensify and prolong the effects of epinephrine.
Beta blockers: These drugs block the intended effects of epinephrine.
Digoxin: Use with epinephrine can increase the risk of developing cardiac dysrhythmias.
Laboratory changes: Epinephrine consumption increases blood sugar levels.

Continuously monitor blood pressure, heart rate, and urine output.
Monitor the IV site for signs of infiltration.
When administering an IV push, give the medication slowly at a rate of $1\text{ mg/minute}$ unless the patient is in cardiac arrest.
Ensure the patient is on a cardiac monitor when receiving the medication intravenously.
Monitor for side effects and adverse reactions; specifically report hypertension, irregular heart rate, or tachycardia.
Continuously monitor blood glucose levels in patients with diabetes.

Instruct patients to report side effects and adverse reactions, such as the sensation of palpitations.
Advise patients to avoid drugs that increase blood pressure, including over-the-counter cold medications and diet pills.
Advise against using adrenergic agonists when breastfeeding.
Instruct patients to take medication exactly as prescribed.
Provide instruction on the proper use of inhaled drugs or drops, requiring a return demonstration from the patient.

The healthcare provider must be informed if the Epipen is used more than twice in one week.
The patient must have the Epipen with them at all times.
Do not refrigerate the Epipen; it should be stored in a cool, dark place.
The Epipen should be used at the very first sign of an allergic reaction.
Inspect the contents for particles before use; do not use the device if the liquid appears pink or brown.
The injection should be administered subcutaneously in the outer thigh and held in place for $5-10\text{ seconds}$ .
After administration, the injection site should be massaged for $10\text{ seconds}$ .
Adverse reactions following use must be reported.

Question: A client is administered epinephrine. The nurse should monitor the client for which development?
- A. Heart rate of $100$
- B. Pupil constriction
- C. Bronchial constriction
- D. BP $176/92$
Answer: D: Hypertension ( $176/92$ ).