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 - Mohawk College 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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