Nursing 1721 - Pharmacology for Nursing

Topic 4A: Adrenergic Agonists

Overview

• Focus on the autonomic nervous system drug classes
• Covers five learning objectives: non-selective adrenergic agonists, Alpha One agonists, Alpha Two agonists, Beta One agonists, Beta Two agonists
• Recommended reading: Section 4.2 in the text for autonomic nervous system basics

Acronym: CAP RN

• C: Classification
  • Breakdown into therapeutic and pharmacologic classifications
• A: Actions
  • Pharmacodynamics: Where and how the drug works in the body
• P: Purposes
  • Applications or indications for drug use
• R: Reactions
  • Includes side effects, adverse effects, drug/food interactions
• N: Nursing Implications
  • Assessments, interventions, patient teaching

Adrenergic Agonists

• Terms: Adrenergic = Sympathetic, Agonist = Mimetic (e.g., sympathomimetic)
• Selective vs. Non-selective: Some drugs target specific receptor sites while others do not
• Catecholamines: Neurotransmitters like norepinephrine, epinephrine, dopamine, serotonin
  • Mao (Monoamine Oxidase): Breaks down catecholamines

Receptor Sites

• Alpha One: Vasoconstriction, pupil dilation, muscle relaxation of the bladder (urinary retention)
• Beta One: Heart - increased heart rate, contractility, renin release
• Beta Two: Lungs - bronchodilation, muscle relaxation in the uterus, increased blood sugar from liver
• Alpha Two: Works in the CNS to inhibit norepinephrine release (vasodilation, decreased BP)

Drug Classes

Non-Selective Adrenergic Agonists

• Prototype: Epinephrine
• Actions: Mimic catecholamines (norepinephrine, epinephrine, dopamine)
• Purposes: Severe allergic reactions, acute bronchospasm, cardiac resuscitation, local bleeding control
• Reactions: Hypertensive crisis, increased cardiac workload, local tissue injury, glaucoma risk
• Considerations: Monitor vital signs, IV site, patient teaching on side effects, and EpiPen use

Alpha One Agonists

• Prototype: Pseudoephedrine, also phenylephrine
• Actions: Selective stimulation of alpha one sites (vasoconstriction)
• Purposes: Relief for upper respiratory infections (decongestant)
• Reactions: Increased blood pressure, urinary retention, jitteriness, insomnia
• Considerations: Monitor blood pressure, educate on over-the-counter medications, side effects

Alpha Two Agonists

• Prototype: Clonidine
• Actions: Inhibition of norepinephrine release in CNS (vasodilation, decreased BP)
• Purposes: Hypertension, ADHD
• Reactions: Hypotension, bradycardia, sedation, rebound hypertension
• Considerations: Monitor blood pressure, education on orthostatic hypotension, alcohol avoidance, compliance with dosing schedule

Beta One Agonists

• Prototype: Dobutamine
• Actions: Increase heart rate, force of contraction, conduction speed
• Purposes: Heart failure, cardiogenic shock
• Reactions: Rapid heart rate, increased workload/oxygen demand, chest pain, dizziness
• Considerations: Monitor ECG, vital signs, urinary output, patient education on side effects

Beta Two Agonists

• Prototype: Albuterol
• Actions: Bronchodilation (primarily in lungs)
• Purposes: COPD, asthma
• Reactions: Hypersensitivity, increased heart rate/blood pressure
• Considerations: Monitor respiratory-related vitals, educate on inhaler use, use of spacer, compliance, side effects