What are the symptoms of opioid toxicity?

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Last updated: February 13, 2025View editorial policy

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From the Guidelines

Opioid toxicity symptoms include central nervous system depression, respiratory depression, and can progress to cardiac arrest.

Key Symptoms

  • Central nervous system depression, characterized by sleepiness and unresponsiveness 1
  • Respiratory depression, marked by slowed and stopped breathing 1
  • Severe life-threatening instability, including severe CNS or respiratory depression, hypotension, or cardiac arrhythmia 1
  • In severe cases, opioid toxicity can cause respiratory arrest and cardiac arrest 1

Additional Considerations

  • Opioid overdose can also lead to hypertension, tachycardia, piloerection, vomiting, agitation, and drug cravings in patients with opioid dependency, particularly after naloxone administration 1
  • Pulmonary edema has been reported with naloxone administration, but it may also be caused primarily by opioid toxicity 1

From the Research

Symptoms of Opioid Toxicity

The symptoms of opioid toxicity can vary in severity and may include:

  • Respiratory depression, which can progress to apnea and death 2
  • Pulmonary edema and congestion, with frothy watery fluid often present in the airways 2
  • Airway occlusion, including positional asphyxia 3
  • Exaggerated respiratory depression and depression of consciousness 3
  • Non-cardiogenic pulmonary edema 4
  • Granulomatous change in the lungs 4
  • Immune system effects, increasing the risk of infectious complications 4
  • Cognitive failure, hallucinations, myoclonus, nausea and vomiting, and local toxicity 5
  • Abdominal cramping and unintentional defecation in cases of naloxone-precipitated opioid withdrawal 6

Severity of Opioid Toxicity

The severity of opioid toxicity can be classified into different grades, with increasing levels of toxicity associated with more severe symptoms, such as:

  • Grade 1 severity: mild symptoms, requiring minimal clinical intervention 3
  • Grade 2 severity: moderate symptoms, requiring more significant clinical intervention 3
  • Grade 3 severity: severe symptoms, requiring intensive clinical intervention 3
  • Complicated heroin overdose cases: requiring specialized care and management 3

Onset of Opioid Toxicity

The onset of opioid toxicity can occur rapidly, with a median time of 17 minutes from heroin injection to clinical intervention 3. Early intervention is critical in managing overdose cases and preventing fatal outcomes 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Opioid Toxicity.

Academic forensic pathology, 2017

Research

The effects of opioids on the lung.

Clinical reviews in allergy & immunology, 2014

Research

Opioid rotation for toxicity reduction in terminal cancer patients.

Journal of pain and symptom management, 1995

Research

Treatment of acute naloxone-precipitated opioid withdrawal with buprenorphine.

The American journal of emergency medicine, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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