Important Safety Information - Naloxone Hydrochloride Auto-Injector

Written by HeyDoctor Medical Team

Important safety information and consumer warnings you should know about naloxone hydrochloride auto-injector.


The risk information provided here is not comprehensive. To learn more, talk about any new medicine with your healthcare provider and pharmacist. The full FDA-approved product labeling can be found at or 1-800-555-DRUG. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.

EVZIO (EVV-zee-oh) (naloxone hydrochloride injection) Auto-Injector

Intramuscular or Subcutaneous Use

You and your caregivers should read this Patient Information leaflet before an opioid emergency happens. This information does not take the place of talking with your healthcare provider about your medical condition or your treatment.

What is the most important information I should know about EVZIO?

EVZIO is used to temporarily reverse the effects of opioid medicines. The medicine in EVZIO has no effect on people who are not taking opioid medicines. Always carry EVZIO with you in case of an opioid emergency.

  • Use EVZIO right away if you or your caregiver think signs or symptoms of an opioid emergency are present, even if you are not sure, because an opioid emergency can cause severe injury or death. Signs and symptoms of an opioid emergency may include:
    • unusual sleepiness and you are not able to awaken the person with a loud voice or rubbing firmly on the middle of their chest (sternum).
    • breathing problems including slow or shallow breathing in someone difficult to awaken or they look like they are not breathing.
    • the black circle in the center of the colored part of the eye (pupil) is very small, sometimes called “pinpoint pupils” in someone difficult to awaken.
  • Family members, caregivers, or other people who may have to use EVZIO in an opioid emergency should know where EVZIO is stored and how to give EVZIO before an opioid emergency happens.
  • Get emergency medical help right away after using the first dose of EVZIO. Rescue breathing or CPR (cardiopulmonary resuscitation) may be given while waiting for emergency medical help.
  • The signs and symptoms of an opioid emergency can return within several minutes after EVZIO is given. If this happens, give additional injections using a new EVZIO auto-injector every 2 to 3 minutes and continue to closely watch the person until emergency help is received.

What is EVZIO?

  • EVZIO is a prescription medicine used in adults and children for the treatment of an opioid emergency such as an overdose or a possible opioid overdose with signs of breathing problems and severe sleepiness or not being able to respond.
  • EVZIO is to be given right away and does not take the place of emergency medical care. Get emergency medical help right away after the first dose of EVZIO, even if the person wakes up.
  • EVZIO is safe and effective in children for known or suspected opioid overdose.

Who should not use EVZIO?

Do not use EVZIO if you are allergic to naloxone hydrochloride or any of the ingredients in EVZIO. See the end of this leaflet for a complete list of ingredients in EVZIO.

What should I tell my healthcare provider before using EVZIO?

Before using EVZIO, tell your healthcare provider about all your medical conditions, including if you:

  • have heart problems
  • are pregnant or plan to become pregnant. Use of EVZIO may cause withdrawal symptoms in your unborn baby. Your unborn baby should be examined by a healthcare provider right away after you use EVZIO.

Tell your healthcare provider about the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How should I use EVZIO?

Read the “Instructions for Use” at the end of this Patient Information leaflet for detailed information about the right way to use EVZIO.

  • You should use EVZIO exactly as prescribed by your healthcare provider.
  • Each EVZIO auto-injector contains only 1 dose of medicine.
  • EVZIO should be injected into the muscle or skin of the outer thigh. It can be injected through clothing if needed.
  • Caregivers should pinch the thigh muscle while injecting EVZIO into a child under the age of one.
  • A Trainer for EVZIO with a separate “Trainer Instructions for Use” leaflet is included with EVZIO. For additional training information and video instructions go to or call 1-855-773-8946.
    • Practice with the Trainer for EVZIO before an opioid emergency happens to make sure you are able to safely use the real EVZIO in an emergency.
    • The Trainer for EVZIO does not contain a needle or medicine. It can be reused to practice your injection. o The red safety guard can be removed and replaced on the Trainer for EVZIO.

What are the possible side effects of EVZIO?

EVZIO may cause serious side effects, including:

  • Sudden opioid withdrawal symptoms. In someone who has been using opioids regularly, opioid withdrawal symptoms can happen suddenly after receiving EVZIO and may include:
    • body aches
    • fever
    • sweating
    • runny nose
    • sneezing
    • goosebumps
    • yawning
    • weakness
    • shivering or trembling
    • nervousness
    • restlessness or irritability
    • diarrhea
    • nausea or vomiting
    • stomach cramping
    • increased blood pressure o increased heart rate

Common side effects of EVZIO include dizziness and injection site redness.

In infants under 4 weeks old who have been receiving opioids regularly, sudden opioid withdrawal may be life-threatening if not treated the right way. Signs and symptoms include: seizures, crying more than usual and increased reflexes. These are not all of the possible side effects of EVZIO. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

How should I store EVZIO?

  • Store EVZIO at room temperature between 59oF to 77oF (15oC to 25oC).
  • Keep EVZIO in its outer case until ready to use.
  • Occasionally check EVZIO through the viewing window of the auto-injector. The solution should be clear. If the EVZIO solution is discolored, cloudy, or contains solid particles, replace it with a new EVZIO. • Your EVZIO has an expiration date. Replace it before the expiration date.
  • Keep EVZIO and all medicines out of the reach of children.

General information about the safe and effective use of EVZIO.

Medicines are sometimes prescribed for purposes other than those listed in a Patient Information leaflet. Do not use EVZIO for a condition for which it was not prescribed. You can ask your pharmacist or healthcare provider for information about EVZIO that is written for health professionals.

What are the ingredients in EVZIO?

Active ingredient: naloxone hydrochloride Inactive ingredients:

  • sodium chloride
  • hydrochloric acid (to adjust pH)
  • water

EVZIO is not made with natural rubber latex.

The views expressed in this article intend to highlight alternative studies and induce conversation. They are the views of the author and do not necessarily represent the views of HeyDoctor, and are for informational purposes only, even if and to the extent that this article features the advice of physicians and medical practitioners. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice.

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