Autonomic Nervous System Regulation

4.5 ANS Medication Classes and Nursing Considerations

Classes of medication, categorized according to neuroreceptor, are further discussed in more detail below. Figure 4.5a summarizes how ANS drugs are classified.

A flowchart depicting the classes of drugs acting on the ANS.
Figure 4.5a Classification of drugs acting on the ANS [Figure 4.5a Image Description]

Table 4.5[1] further contrasts agonist and antagonist medications for each ANS neuroreceptor.

Receptor Stimulation (Agonist) Inhibition (Antagonist)
Nicotinic
  • Nicotine is a muscle relaxant with CNS effects.
  • Nicotine patch is used for nicotine addiction by slowly reducing dose and avoiding withdrawal effects
  • Not clinically applicable
Muscarinic
  • Pilocarpine causes muscle contraction; assists with glaucoma by contracting ciliary muscle and draining fluid
  • Atropine in small doses inhibits secretions; in moderate doses increases heart rate; in large doses decreases gastrointestinal motility
Alpha-1
(found in smooth muscles)
  • Tamsulosin relaxes smooth muscle in bladder/prostate to improve urine flow and also decreases blood pressure due to vasodilation
Alpha-2
(found in brain and periphery)
  • Clonidine decreases CNS outflow to treat ADHD and also reduces blood pressure and heart rate
  • Limited clinical use
Beta-1
(found on heart and kidneys)
  • Dobutamine increases heart rate, force of heart contraction, and speed of conduction between SA to AV nodes
  • Selective B blocker: Metoprolol works on Beta-1 receptors to decrease blood pressure and heart rate
Beta-2
(found on the lungs)
  • Nonselective B blocker: Propranolol works on Beta-2 and Beta-1 receptors; decreases blood pressure but can also cause bronchoconstriction
Catecholamines stimulate multiple adrenergic receptors
  • Epinephrine and Norepinephrine: stimulate alpha- and beta-receptors on target organs, causing increased heart rate and vasoconstriction for improved blood flow to essential organs
  • Dopamine has dose-dependent effects that target arteries in the kidneys, heart, and brain
  • Not clinically applicable

Supplementary Videos:  See the supplementary videos below related to sympathetic and parasympathetic nervous system medications.

Sympathetic Nervous System Drugs

[2]

 

Parasympathetic Nervous System Drugs

[3]

Image Descriptions

Figure 4.5a Classification of drugs acting on the ANS Image Description

Drugs acting on the ANS are classified by the receptor type affected:

  • Adrenergic drugs
    • α1, α2
    • β1, β2
  • Cholinergic drugs
    • nicotinic (N1, N2)
    • muscarinic (M1, M2, M3)

Drugs acting on the ANS are classified by the effect on the receptor:

  1. agonist
  2. antagonist

[Return to Figure 4.5a]

  1. This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain ↵
  2. Forciea, B. (2018, January 12). Sympathetic nervous system drugs. [Video]. YouTube. All rights reserved.  Video used with permission.  https://youtu.be/-e_s-jTPtm4 ↵
  3. Forciea, B. (2018, February 2). Parasympathetic nervous system drugs. [Video]. YouTube. All rights reserved. Video used with permission. https://youtu.be/ZSRk_NkbBPg ↵

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Fundamentals of Nursing Pharmacology - 1st Canadian Edition Copyright © 2023 by Chippewa Valley Technical College; Amanda Egert; Kimberly Lee; and Manu Gill is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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