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Naloxone

Supportive Care

Brand names:

 Kloxxado®, Narcan®, Rextovy®, Zimhi®, Narcan OTC®, RiVive OTC®

Often used for:

Treating an opioid overdose

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What is naloxone?

Naloxone is a medicine used to treat or reverse the effects of taking too much opioid medication or an opioid overdose. It can also be used to decrease certain side effects of opioids. Common opioid medicines include hydrocodone, morphine, hydromorphone, oxycodone, fentanyl, and methadone. Naloxone works by blocking opioid effects on the body.

Naloxone can cause withdrawal symptoms in people who have taken opioids for a long time or who have a physical dependence on the medicine.

Naloxone is safe and won’t harm someone if they haven’t taken opioids. If you give naloxone, always call 911 and seek medical help right away.

Brain

May be given as a liquid spray into the nose

 
Brain

May be given as a shot under the skin (subcutaneous injection)

 
Brain

May be given as a shot into a muscle (intramuscular injection) 

 
Brain

May be given into a vein by IV

 
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Possible side effects

In general, naloxone has very few side effects and will not harm someone if they have not taken opioids. Possible side effects include:

  • Dry, runny, or stuffy nose (if given by nose)
  • Irritation of the nose (if given by nose)
  • Pain or irritation at the injection site (if given by injection)
  • Headache
  • Muscle pain
  • Feeling tired or weak
  • Dizziness
  • Change in taste
  • Dry skin
  • Flushed skin or hot flashes
  • Withdrawal symptoms which may include fast heart rate, sweating, shaking, chills, nausea, vomiting, anxiety, irritability

Call your care team right away if your child has symptoms of an allergic reaction. These may include: rash, hives, itching, runny nose, fever, chills, headache, muscle ache, shortness of breath, coughing, tightness in the throat, swelling of the face or neck, dizziness, low blood pressure, or pain in the chest, side, or back.  

Not all patients who take naloxone will have these side effects and there might be others not listed. Some side effects can be severe. Please report any symptoms or side effects to your health care provider or pharmacist. 

Find more information on side effects.

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Tips for patients and families

Be sure to discuss all questions and instructions with your health care provider or pharmacist.

  • Give naloxone if you suspect an opioid overdose. Naloxone has no effect if someone has not taken opioids.
  • Naloxone comes in several forms. Be sure you know how to give the medicine and are prepared to use it in an emergency.
  • Know how to recognize the signs of opioid overdose, such as slow or irregular breathing, slow or irregular heartbeat, pale or clammy skin, blue lips or fingernails, small pupils, drowsiness, and not responding to sound or touch.
  • After getting naloxone, people may show signs of withdrawal (see side effects above). Let health care providers know about any symptoms after giving the medicine.
  • The effects of naloxone are temporary. Overdose symptoms can come back after naloxone wears off which may require additional doses. Always seek medical care after giving the medicine.

Naloxone at home

  • Always follow the instructions provided by the pharmacist.
  • After giving this medicine, seek emergency medical assistance right away.
  • Nose spray: Place the patient on their back. Support the neck and gently tilt back the head with your hand. Insert the tip of the spray nozzle into the nose and press the plunger to give the medicine.
  • Prefilled syringes: Insert the needle into the outer thigh. The medicine can be given through clothes.
  • Auto-injectors: Hold the device next to the outer thigh. Press down on the plunger. The medicine can be given through clothes. Throw away pre-filled medications devices after each use. Do not reuse.
  • Store at room temperature and protect from heat and light.
  • Do not use the medicine past the expiration date.

Learn more about naloxone nasal spray

Learn more about naloxone injection

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Always check the medication label. Many medicines look the same. Do not take any new medicine, including over-the counter medicines or supplements, without checking with your doctor or pharmacist. Talk to your doctor or pharmacist about what to do in the case of a missed dose, allergic reaction, or medical emergency. 

This information is not intended to be a complete guide and is not a substitute for talking with your provider. Medicine names, appearance, formulas, or availability may vary by clinic location. Always follow the instructions given by your care team.

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Reviewed: May 2025