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Generic Name: naloxone (nah LOX one)
Brand Names: Evzio, Narcan

What is naloxone?

Naloxone blocks or reverses the effects of opioid medication, including extreme drowsiness, slowed breathing, or loss of consciousness. An opioid is sometimes called a narcotic.

Naloxone is used to treat a narcotic overdose in an emergency situation. This medicine should not be used in place of emergency medical care for an overdose.

Naloxone is also used to help diagnose whether a person has used an overdose of an opioid.

Important information

In an emergency situation it may not be possible before you are treated to tell your caregivers about your health conditions or if you are pregnant or breast feeding. Make sure any doctor caring for you afterward knows that you have received naloxone.

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Drinking alcohol can increase certain side effects of naloxone.

Naloxone may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

If you are using any narcotic pain medication, the pain-relieving effects of the narcotic will be reversed while you are also receiving naloxone.

Before receiving naloxone

You should not receive this medicine if you are allergic to naloxone.

To make sure naloxone is safe for you, tell your doctor if you have:

  • heart disease.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant.

It is not known whether naloxone passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

In an emergency situation it may not be possible to tell your caregivers if you are pregnant or breast feeding. Make sure any doctor caring for your pregnancy or your baby knows you have received naloxone.

How is naloxone given?

Naloxone is injected into a muscle, under the skin, or into a vein through an IV. The injection may be given by a healthcare provider, emergency medical provider, or a family member or caregiver who is trained to properly give a naloxone injection.

If you are a caregiver or family member giving a naloxone injection, read all instructions when you first get this medicine. If provided, use the "trainer" device to practice giving an injection so you will know how to do it in an emergency. Ask your doctor or pharmacist if you have any questions.

Be sure you know how to recognize the signs of an opioid overdose in the person you are caring for. Overdose symptoms may include:

  • slowed breathing, or no breathing;

  • very small or pinpoint pupils in the eyes;

  • slow heartbeats; or

  • extreme drowsiness, especially if you are unable to wake the person from sleep.

Even if you are not sure an opioid overdose has occurred, if the person is not breathing or is unresponsive, give the naloxone injection right away and then seek emergency medical care.

Do not assume that an overdose episode has ended if symptoms improve. You must get emergency help after giving a naloxone injection.

Naloxone injected into a muscle is given in the outer thigh. In an emergency, you may give an injection through the person's clothing.

After injecting naloxone, stay with the person and watch for continued signs of overdose. You may need to give another injection every 2 to 3 minutes until emergency help arrives. Follow all medication instructions carefully.

Each Evzio auto-injector is for one use only. Throw away after one use, even if there is still some medicine left in it after injecting a dose.

Store naloxone at room temperature away from moisture and heat. Keep the auto-injector in its outer case until you are ready to use it. Do not use the medicine if it has changed colors or has particles in it. Call your pharmacist for new medication.

What happens if I miss a dose?

Because you will receive naloxone in an emergency situation, you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while using naloxone?

Avoid leaving a person alone after giving him or her a naloxone injection. An overdose can impair a person's thinking or reactions.

Naloxone side effects

Get emergency medical help if you have signs of an allergic reaction to naloxone: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Because naloxone reverses opioid effects, this medicine may cause sudden withdrawal symptoms such as:

  • nausea, vomiting, diarrhea, stomach pain;

  • fever, sweating, body aches, weakness;

  • tremors or shivering, fast heart rate, pounding heartbeats, increased blood pressure;

  • feeling nervous, restless, or irritable;

  • goosebumps, shivering;

  • runny nose, yawning; or

  • (in babies younger than 4 weeks old) seizures, crying, stiffness, overactive reflexes.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Naloxone dosing information

Usual Adult Dose for Opioid Overdose:

0.4 to 2 mg/dose IV/IM/subcutaneously. May repeat every 2 to 3 minutes as needed. Therapy may need to be reassessed if no response is seen after a cumulative dose of 10 mg.

Continuous infusion: 0.005 mg/kg loading dose followed by an infusion of 0.0025 mg/kg/hr.

Usual Pediatric Dose for Opioid Overdose:

Infants, Children, and Adolescents:
Opioid intoxication (full reversal):
IV (preferred) or Intraosseous (IO): Note: May be administered IM, Subcutaneous, or endotracheal tube (ET), but onset of action may be delayed, especially if patient has poor perfusion; ET preferred if IV or IO route not available; doses may need to be repeated.

Infants and Children less than or equal to 5 years or less than or equal to 20 kg: 0.1 mg/kg/dose; repeat every 2 to 3 minutes if needed; may need to repeat doses every 20 to 60 minutes.

Children greater than 5 years or greater than 20 kg and Adolescents: 2 mg/dose; if no response, repeat every 2 to 3 minutes; may need to repeat doses every 20 to 60 minutes.

ET: Optimal endotracheal dose unknown; current expert recommendations are 2 to 3 times the IV dose.

Manufacturer recommendations: IV (preferred), IM, Subcutaneous:
Initial: 0.01 mg/kg/dose; if no response, a subsequent dose of 0.1 mg/kg may be given
Note: If using IM or Subcutaneous route, dose should be given in divided doses.

Continuous IV infusion:
Children: If continuous infusion is required, calculate the initial dosage/hour based on the effective intermittent dose used and duration of adequate response seen; titrate dose; a range of 2.5 to 160 mcg/kg/hour has been reported; taper continuous infusion gradually to avoid relapse.

Respiratory depression [therapeutic opioid use (e.g., postanesthesia)]:
PALS Guidelines, 2010: IV: 0.001 to 0.005 mg/kg/dose; titrate to effect
Manufacturer recommendations: Initial: 0.005 to 0.01 mg/kg; repeat every 2 to 3 minutes as needed based on response.

Opioid-induced pruritus:
Children and Adolescents: Limited data available

What other drugs will affect naloxone?

Other drugs may interact with naloxone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Where can I get more information?

  • Your pharmacist can provide more information about naloxone.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use naloxone only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2015 Cerner Multum, Inc. Version: 3.04. Revision Date: 2015-08-15, 2:17:37 AM.