Autonomic Nervous System Regulation

4.11 Alpha-2 Antagonists

Clonidine is an Alpha-2 antagonist.

Mechanism of Action:  Clonidine reduces sympathetic outflow from the central nervous system and decreases peripheral resistance and renal vascular resistance.

Indications for Use: Clonidine is used to treat hypertension (HTN) and attention deficit hyperactivity disorder (ADHD).

Nursing Considerations Across the Lifespan: Alpha-2 antagonists can be used safely in pediatric and older adult populations.  For pediatrics, dose adjustments need to be made based on the child’s weight, and titrated slowly.  In older adult populations, dose adjustments are necessary when there is underlying kidney dysfunction.

Nurses need to monitor blood pressure and pulse rate frequently when giving these medications. Dosage is usually adjusted to the client’s blood pressure and can cause hypotension, bradycardia, and sedation. Rebound hypertension may occur if stopped abruptly.

Patient Teaching & Education: Clients should be taught the importance of adhering to the same dosing schedule each day.  Clients may experience orthostatic blood pressure changes and should be cautioned against the use of alcohol while taking this medication.  Additionally, clients may experience increased susceptibility to blood pressure changes when exercising and exposed to hot environments.  If the client experiences mental depression as a side effect of the medication, a different medication therapy may be needed.[1]

Clonidine Medication Card

Now let’s take a closer look at the medication grid on clonidine.[2][3] Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.

Medication Card 4.11.1: Clonidine

Class: Alpha-2 Agonist

Prototypes: Clonidine

Therapeutic Effects

  • treat hypertension, or ADHD

Administration

  • PO (immediate-release and slow-release), transdermal
  • dosage is usually adjusted to clients BP and tolerance

Indications

  • Treatment of attention-deficit/ hyperactivity disorder (monotherapy or as adjunctive therapy)
  • Hypertension (immediate-release tablet and transdermal patch)
  • Vasomotor symptoms associated with menopause

Side Effects

  • hypotension
  • bradycardia
  • sedation
  • rebound hypertension if stopped abruptly

Nursing Considerations

  • Monitor blood pressure and pulse rate frequently
  • Never stop medication abruptly

Alpha-2 Antagonists

A2 antagonists are used in research with limited clinical application.[4]


  1. uCentral from Unbound Medicine. https://www.unboundmedicine.com/ucentral
  2. This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain.
  3. UpToDate (2021). Clonidine. https://www.uptodate.com/contents/search
  4. This work is a derivative of Daily Med by U.S. National Library of Medicine in the public domain.

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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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