Chapter 15: Adrenergic Agonists & Antagonists

Adrenergic Agonists & Antagonists establishes a foundational understanding of the autonomic nervous system as the involuntary controller of visceral functions, such as cardiac rhythm and respiratory rate, differentiating it from the voluntary somatic system. The text focuses on sympathomimetics, drugs that replicate the effects of norepinephrine and epinephrine by stimulating specific receptors. Alpha-1 stimulation is linked to vascular constriction and increased blood pressure, while Alpha-2 activation serves to inhibit neurotransmitter release, promoting vasodilation. Beta-1 receptors primarily influence myocardial contractility and heart rate, whereas Beta-2 receptors govern bronchodilation and gastrointestinal relaxation. The chapter contrasts nonselective drugs like epinephrine, vital for treating anaphylactic shock due to their broad receptor impact, with selective agents like albuterol, which provides targeted relief for asthma with reduced cardiac side effects. Shifting to sympatholytics, the discussion covers adrenergic blockers used to manage hypertension, heart failure, and benign prostatic hyperplasia. It emphasizes the clinical utility of selective beta-blockers like atenolol and discusses the significance of intrinsic sympathomimetic activity in certain medications. A significant portion of the material is dedicated to the nursing process, highlighting critical safety protocols such as monitoring for tissue necrosis during intravenous administration of dopamine, recognizing the potential for rebound nasal congestion from over-the-counter sprays, and providing life-saving patient education regarding the use of emergency autoinjectors. By combining pharmacokinetic profiles with practical clinical judgment, this chapter serves as a vital guide for managing sympathetic drug therapy and ensuring patient safety.