4.4 ANS Medication Classes
Classes of medication, categorized according to neuroreceptor, are further discussed in more detail in the following sections. Table 4.4[1] contrasts agonist and antagonist medications for each ANS neuroreceptor.
Table 4.4 Comparison of Prototype Medications That Stimulate Versus Inhibit PNS and SNS Receptors
Receptor |
Stimulation (Agonist) |
Inhibition (Antagonist) |
|---|---|---|
| Nicotine | Nicotine is a muscle relaxant with CNS effects. A 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 | Pseudoephedrine and Phenylephrine cause vasoconstriction, decreased swelling of mucus membranes, and decreased secretions | Tamsulosin relaxes smooth muscle in bladder/prostate to improve urine flow and also decreases blood pressure due to vasodilation |
| Alpha-2 | Clonidine decreases CNS outflow to treat ADHD and also reduces blood pressure and heart rate | Limited clinical use |
| Beta-1 | 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 | Albuterol used for bronchodilation | 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 |
See the supplementary YouTube videos in the boxes below related to sympathetic and parasympathetic nervous system medications.
- This work is a derivative of DailyMed by U.S. National Library of Medicine in the Public Domain. ↵
- Forciea, B. (2018, January 12). Sympathetic nervous system drugs [Video]. YouTube. All rights reserved. Video used with permission. https://youtu.be/-e_s-jTPtm4 ↵
- Forciea, B. (2018, February 2). Parasympathetic nervous system drugs [Video]. YouTube. All rights reserved. Video used with permission. https://youtu.be/ZSRk_NkbBPg ↵