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Generic name: naloxone (nasal)
Drug class: Antidotes

Medically reviewed by  A Ras MD.

What is Narcan used for?

Narcan is used to avoid side effects from some drugs. It is used to treat some overdoses. Narcan may be given to you for other reasons. Talk to your doctor.


NARCAN (naloxone hydrochloride) Nasal Spray is a pre-filled, single dose intranasal spray. Chemically, naloxone hydrochloride is the hydrochloride salt of 17-Allyl-4,5α-epoxy-3,14-dihydroxymorphinan-6-one hydrochloride with the following structure:


C19H21NO4∙ HCl

M.W. 363.84

Naloxone hydrochloride, an opioid antagonist, occurs as a white to slightly off-white powder, and is soluble in water, in dilute acids, and in strong alkali; slightly soluble in alcohol; practically insoluble in ether and in chloroform.

Each NARCAN Nasal Spray contains a 2 mg or 4 mg single dose of naloxone hydrochloride (equivalent to 1.8 mg or 3.6 mg of naloxone) in a 0.1 mL (100 microliter) aqueous solution.

Inactive ingredients include benzalkonium chloride (preservative), disodium ethylenediaminetetraacetate (stabilizer), sodium chloride, hydrochloric acid to adjust pH, and purified water. The pH range is 3.5 to 5.5.

Mechanism of Action

Naloxone hydrochloride is an opioid antagonist that antagonizes opioid effects by competing for the same receptor sites.

Naloxone hydrochloride reverses the effects of opioids, including respiratory depression, sedation, and hypotension. It can also reverse the psychotomimetic and dysphoric effects of agonist-antagonists such as pentazocine.

Before taking Narcan, tell your doctor:

  • If you are allergic to Narcan; any part of this medicine; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Narcan with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Narcan?

  • Tell all of your health care providers that you take Narcan. This includes your doctors, nurses, pharmacists, and dentists.
  • If you are addicted to pain drugs and are given Narcan, you may have signs of withdrawal. Talk with your doctor.
  • In infants younger than 4 weeks old who have been getting opioid drugs on a regular basis, sudden withdrawal may be life-threatening if not treated right away. Get medical help right away if your child has a seizure, is crying more than normal, or has increased reflexes.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.
  • If Narcan is used during pregnancy, it may cause withdrawal in the unborn baby. A doctor will need to check on the unborn baby after Narcan is used.

How is Narcan best taken?

Use Narcan as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • For the nose only.
  • Your doctor will teach you how to take Narcan.
  • Be sure you know how to use before an emergency happens. Read the package insert and instructions for use that come with Narcan. If you have any questions about how to use Narcan, talk with the doctor or pharmacist.
  • Someone else may have to give Narcan. Be sure others know where Narcan is stored and how to give it if needed.
  • After using Narcan, overdose symptoms may go away and come back. It is important to get medical help right away after using Narcan.
  • Each nasal spray has only 1 dose and cannot be reused. If another dose is needed, you will need to use new nasal spray.
  • If using more than 1 dose, switch nostrils with each dose.
  • Do not use if Narcan is out of date. Get a new one.
  • If Narcan freezes, you may let it thaw at room temperature before use. If an emergency happens and Narcan is frozen, do not wait for it to thaw. Get medical help right away.

What do I do if I miss a dose?

  • Get medical help right away.

What are the side effects of Narcan that I need to call my doctor about immediately?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

  • Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
  • Signs of high or low blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
  • Seizures.
  • Shortness of breath.
  • Chest pain or pressure.
  • Fast or abnormal heartbeat.
  • A burning, numbness, or tingling feeling that is not normal.
  • Feeling agitated.
  • Mood changes.
  • Hallucinations (seeing or hearing things that are not there).
  • Shakiness.
  • Sweating a lot.

What are some other side effects of Narcan?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

  • Muscle pain.
  • Muscle spasm.
  • Headache.
  • Dry nose.
  • Runny or stuffy nose.
  • Swelling in the nose.
  • Constipation.
  • Tooth pain.
  • Dry skin.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

If overdose is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Narcan?

  • Store in the original container at room temperature.
  • Do not freeze.
  • Protect from heat and light.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.



  • NDC 69547-212-04
    0.1 mL intranasal spray per unit
    For use in the nose only
    Rx Only
  • NARCAN®(naloxone HCl)
    NASAL SPRAY 2 mg
  • Use NARCAN® Nasal Spray for known or suspected opioid overdose in
    adults and children.
  • Important: For use in the nose only.
  • Do not remove or test the NARCAN® Nasal Spray until ready to use.
  • This box contains four (4) 2-mg doses of naloxone HCl in 0.1 mL of nasal spray.
  • Four Pack

Narcan (naloxone HCl) Nasal Spray 2 mg carton label


  • NDC 69547-353-02
    0.1 mL intranasal spray per unit
    For use in the nose only
    Rx Only
  • NARCAN®(naloxone HCl)
    NASAL SPRAY 4 mg
  • Use NARCAN® Nasal Spray for known or suspected
    opioid overdose in adults and children.
  • Important: For use in the nose only.
  • Do not remove or test the NARCAN® Nasal Spray
    until ready to use
  • This box contains two (2) 4-mg doses of naloxone
    HCl nasal spray
  • Two Pack
    Opioid Overdose Response Instructions
Narcan (naloxone HCl) Nasal Spray 4 mg carton label


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