Naloxone (Narcan, Evzio)
Generic name: Naloxone (na LOKS one)
- Nasal spray: 2 mg/0.1 mL, 4 mg/0.1 mL
- Injection: 0.4 mg/1 mL, 1 mg/1 mL
All FDA black box warnings are at the end of this fact sheet. Please review before taking this medication.
What Is Naloxone And What Does It Treat?
Naloxone is a medication designed to rapidly reverse opioid overdose. Naloxone is an opioid antagonist, meaning it binds to the opioid receptors to reverse/block the effects of other opioids such as heroin or certain pain medications (e.g., oxycodone, morphine, hydrocodone). After administering naloxone, you should still immediately seek emergency healthcare.
Naloxone has no effect in people who have not taken opioids.
Narcan® is a nasal spray form of naloxone. A generic formulation is available. Naloxone is also available as an auto-injectable device with electronic voice instruction system named Evzio®.
Anyone can carry naloxone on hand in case of emergencies.
Who Should Have Naloxone On Hand?
Some populations that may particularly benefit include:
All 50 states of the USA allow for naloxone use via prescription from a physician. Most states allow for behind-the-counter (without a prescription) naloxone purchase. Please check with your local pharmacy for pertinent legal information.
- Anyone who is taking opioids or is at risk of an overdose
- Family, friends, or acquaintances of someone who may be at risk of an opioid overdose
- Healthcare professionals
- First responders, including police, firefighters, and EMTs
Naloxone is a drug used in an emergency to reverse an opioid overdose. Naloxone is not a replacement for emergency medical care for an overdose. Even if the patient wakes up or improves, you should still seek emergency medical assistance.
What Is The Most Important Information I Should Know About Naloxone?
If the patient is opioid-dependent, use of naloxone may cause opioid withdrawal. Signs of opioid withdrawal include body aches, diarrhea, fast heart rate, high blood pressure, fever, and irritability.
There is limited data on naloxone use in pregnant women to inform about drug-associated risk. It is important to discuss the risks and benefits of continued treatment with your doctor and caregivers.
Are There Specific Concerns About Naloxone And Pregnancy?
Naloxone crosses the placenta and may precipitate withdrawal in the fetus, in addition to the opioid-dependent mother. The fetus should be evaluated for signs of distress after naloxone is used.
Naloxone did not appear to cause birth defects during animal studies.
There is no information regarding the presence of naloxone in human milk or its effects on breastfed infants or on milk production. Naloxone does not affect prolactin or oxytocin hormone levels.
What Should I Discuss With My Healthcare Provider Before Taking Naloxone?
- If you have allergies to any medications
- Any other psychiatric or medical problems you have, including a history of heart problems
- All other medications you are currently taking (including over the counter products, herbal and nutritional supplements)
- Other non-medication treatments you are receiving, such as talk therapy or counseling. Your provider can explain how these different treatments work with the medication.
- If you are pregnant, plan to become pregnant, or are breast-feeding
- If you use illegal drugs or narcotics
How Do I Identify An Opioid Overdose?
Signs and symptoms of an opioid overdose may include:
- Loss of consciousness or unusual sleepiness
- Not responding to a loud voice
- Breathing problems such as slow, shallow, or cessation of breathing
- The black circle in the center of the eye (pupil) becomes very small (pinpoint pupils)
Certain people are at an increased risk for an opioid overdose:
- People with opioid use disorder
- People who may have a reduced opioid tolerance (following detoxification, release from incarceration, cessation of treatment)
- People who use prescription opioids, in particular those taking higher doses
- People who use opioids in combination with other sedating substances (such as alcohol or benzodiazepines)
- Household members of people in possession of opioids (including prescription opioids)
Depending on the state you live in, friends, family members, and others in the community may give naloxone to someone who has overdosed.
How Should I Administer Naloxone?
Evzio® is a prefilled auto-injection device. Each device contains a single dose of naloxone and cannot be reused. Once activated, the device provides verbal instruction to the user and it should be injected into the outer thigh. Evzio® may be administered through clothing (i.e., pants or jeans) if necessary. If symptoms return, additional doses may be administered every 2 to 3 minutes until emergency services arrive or the patient responds positively.
Narcan® is a prefilled nasal spray. It is also available in generic formulation. Each device contains a single dose of naloxone and cannot be reused. The patient should be placed flat on their back, with the head tilted back supporting the neck, when administering the spray. The first dose is given as one spray into one nostril. If there is no recovery in 2-3 minutes, the dose is repeated in the other nostril. The spray may be repeated every 2 to 3 minutes in alternating nostrils until emergency services arrive or the patient responds positively.
Naloxone does not take the place of emergency medical care. Emergency medical services should be contacted and CPR may be performed on the patient.
Since naloxone is an opioid blocker designed to rapidly reverse opioid overdose, it can cause withdrawal symptoms if used in patients who are dependent on opioids. It should be used in an emergency situation if a patient is unresponsive and opioid overdose is suspected. Naloxone has no effect in people who have not taken opioids.
What Should I Avoid While Taking Naloxone?
In patients who has been using opioids regularly, opioid withdrawal symptoms can occur after receiving naloxone and may include: body aches, fever, sweating, running nose, sneezing, goose bumps, yawning, weakness, shivering or trembling, nervousness, restlessness or irritability, diarrhea, nausea, vomiting, stomach cramping, increased blood pressure, and increased heart rate.
What Are Possible Side Effects Of Naloxone?
Common side effects of Evzio® include dizziness and injection site redness.
Naloxone may interact with certain cough/cold medications and anti-diarrheal medications. Your pharmacist or doctor will help you to determine if other medications you take can interfere with the effects of naloxone.
What Other Medications May Interact With Naloxone?
Depending on the opioids overdosed, naloxone should show a response in 2 to 3 minutes. Otherwise, the medication can be readministered until medical services arrive or the patient responds positively.
How Long Does It Take For Naloxone To Work?
Naloxone nasal spray and the auto-injectable device should be stored at room temperature, and not frozen. It should be kept in the box until ready to use.
How Should Naloxone Be Stored?
There are no FDA black box warnings for naloxone.
Summary Of Black Box Warnings
©2019 The College of Psychiatric and Neurologic Pharmacists (CPNP). CPNP makes this document available under the Creative Commons Attribution-No Derivatives 4.0 International License. Last Updated: January 2016.
This information is being provided as a community outreach effort of the College of Psychiatric and Neurologic Pharmacists. This information is for educational and informational purposes only and is not medical advice. This information contains a summary of important points and is not an exhaustive review of information about the medication. Always seek the advice of a physician or other qualified medical professional with any questions you may have regarding medications or medical conditions. Never delay seeking professional medical advice or disregard medical professional advice as a result of any information provided herein. The College of Psychiatric and Neurologic Pharmacists disclaims any and all liability alleged as a result of the information provided herein.