Opioid Antagonists


4.7 out of 5 (50 Reviews)



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Expiration Date

28 Feb 2026

Last Reviewed

1 Mar 2023

Estimated Time To Finish

60 Minutes

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Activity Description

Opioid receptor antagonists block one or more of the opioid receptors in the central or peripheral nervous system. Opioid receptors are specific transmembrane neurotransmitter receptors that couple G-proteins, which upon stimulation by endogenous or exogenous opioids, leading to the intracellular process of signal transduction. The two most commonly used centrally acting opioid receptor antagonists are naloxone and naltrexone. Naloxone comes in intravenous, intramuscular, and intranasal formulations and is FDA-approved for the use in an opioid overdose and the reversal of respiratory depression associated with opioid use. Naltrexone is available in both oral and long-acting injectable formulations and is FDA-approved to treat opioid and/or alcohol maintenance treatment. The most commonly used peripheral opioid receptor antagonist is methylnaltrexone, which is a potent competitive antagonist acting at the digestive tract and is also FDA-approved for the treatment of opioid-induced constipation. This activity outlines the indications, mechanism of action, methods of administration, important adverse effects, contraindications, monitoring, and toxicity of opioid antagonists, so providers can direct patient therapy to optimal outcomes to combat opioid overdose, misuse, or adverse effects.

Target Audience

This activity has been designed to meet the educational needs of physicians.

Learning Objectives

At the conclusion of this activity, the learner will be better able to:

  • Identify the mechanism of action of various opioid antagonist medications.
  • Summarize the different indications for the various opioid antagonist agents.
  • Review the adverse event profile of opioid antagonists.
  • Outline the importance of collaboration and communication among interprofessional team members to improve outcomes and treatment efficacy for patients who might benefit from therapy with opioid antagonists, especially in light of the ongoing opioid crisis.


StatPearls requires everyone who influences the content of an educational activity to disclose relevant financial relationships with ineligible companies that have occurred within the past 24 months. All relevant conflict(s) of interest have been mitigated. Hover over contributor names for financial disclosures. None of the planners of this educational activity have any relevant financial relationships to disclose.

COMMERCIAL SUPPORT: This activity has received NO commercial support.

Continuing Education Accreditation Information

This activity has been planned and implemented in accordance with the accreditation requirements and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint providership of the Quillen College of Medicine, East Tennessee State University, and StatPearls, LLC. The Quillen College of Medicine, East Tennessee State University is accredited by the ACCME to provide continuing medical education for physicians.

Quillen College of Medicine, East Tennessee State University designates this activity for a maximum of 1.00 AMA PRA Category 1 CreditsTM. Physicians should only claim credit commensurate with the extent of their participation in the activity.

This activity is reported to the following Maintenance of Certification (MOC) boards:
American Board of Internal Medicine
  • Critical Care Medicine
  • Internal Medicine
American Board of Pathology
  • Chemical Pathology
American Board of Pediatrics
  • Medical Toxicology

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  1. Register for the activity and create a StatPearls login.     
  2. Review the target audience, learning objectives, and disclosure information.
  3. Study the educational content in the activity.
  4. Choose the best answer to each activity test question. To receive credit, you must pass the test questions with a minimum score of 100%.
  5. Complete the post-activity assessment.
  6. Obtain a certificate.

For information on the applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.


Faculty may discuss investigational products or off-label uses of products regulated by the US Food and Drug Administration. Readers should verify all information before employing any therapies described in this educational activity.

The information provided for this activity is for continuing education purposes only and is not meant to substitute for the independent medical/clinical judgment of a healthcare provider relative to diagnostic and treatment options of a specific patient’s medical condition. The information presented does not necessarily reflect the views of StatPearls or any commercial supporters of educational activities on statpearls.com. StatPearls specifically disclaims responsibility for any adverse consequences resulting directly or indirectly from information in the course, for undetected error, or through a participant's misunderstanding of the content.

Cancellation Policy: Cancellations must be received in writing and a money-back guarantee is provided if not completely satisfied.

  • StatPearlsand and Quillen College of Medicine, East Tennessee State University reserve the right to cancel any course due to unforeseen circumstances. StatPearls andQuillen College of Medicine, East Tennessee State University will not be responsible for other expenses incurred by the participant in the unlikely event that the program is canceled.

Medium or Media Used:

  • Computer Requirements: Internet Access
  • E-mail Address

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