If you or someone you know takes an opioid medication, your doctor may suggest that you have Narcan available. (Opioids are medications used for pain.)

Narcan is used in people of all ages if opioid overdose happens or has possibly happened. Narcan is usually given by a caregiver or loved one if they think opioid overdose has occurred.

After Narcan has been given, 911 or your local emergency number should be called right away. Administering Narcan is not a substitute for emergency medical care for opioid overdose.

Narcan basics

Narcan contains the active drug naloxone. (The active drug is what makes a medication work.) Narcan is classified as an opioid antagonist.

This medication comes as a nasal spray. Each container of Narcan holds one dose of medication that’s given as a spray into one nostril.

Narcan is a brand-name drug. There’s also a generic form of Narcan available. You can purchase Narcan without a prescription. And it’s available at many pharmacies.

Read on to learn about how Narcan is given, its uses, side effects, and more.

Below is information about Narcan’s recommended dosage. But be sure to follow dosage guidance from your doctor or healthcare professional.

If you’re experiencing opioid overdose, typically you’ll need someone else to treat you with Narcan. Make sure that a caregiver or someone you know understands how to give Narcan doses.

Form and strength

Narcan comes as a nasal spray in a strength of 4 milligrams (mg). It comes in a box containing two nasal spray devices. Each nasal spray device contains one 4-mg dose.

Note: Narcan nasal spray used to come in a 2-mg strength as well. This strength has been discontinued and is no longer available.

Recommended dosage

The recommended first dose of Narcan, for people of all ages, is one 4-mg spray into one nostril. (The pediatric dosage of Narcan is the same as the drug’s adult dosage.) Whether to give more doses depends on whether the person affected is responsive and starts breathing normally or not. If not, another dose should be given 2 to 3 minutes after the first dose.

Narcan doses should be given every 2 to 3 minutes until the person affected is responsive and starts breathing normally or emergency personnel arrive. Each dose should be alternated between the right and left nostrils.

Do not reuse the Narcan nasal spray device after giving one dose. Use a new nasal spray device for each dose.

911 (or your local emergency number) should be called right away after giving a dose of Narcan.

There’s no initial dose or maximum dose of Narcan. You can’t give too much Narcan to someone. For more information about Narcan’s dosage, see this detailed article.

Questions Narcan’s dosing

Below, we answer some common questions related to Narcan’s dosages.

  • Will I need to use Narcan long term? No, Narcan is meant to be used only in emergency situations for opioid overdose. It’s not meant to be taken regularly over a long period of time. If you’re taking an opioid medication, you may want to ask your doctor about having Narcan available in case an overdose occurs.
  • Should I take Narcan with food? Narcan can be given on a full or empty stomach.
  • How long does Narcan take to work? Narcan begins working right away. Someone receiving it may become responsive or start breathing normally 2 to 3 minutes after the first dose is given to them. But keep in mind that repeated doses of Narcan are sometimes needed.

Narcan is usually given by a caregiver or loved one if someone is affected by opioid overdose.

Your doctor or pharmacist will explain how Narcan should be given. They’ll also explain how much to give and how often. Be sure to follow their instructions.

How and when to give Narcan

Narcan comes as a nasal spray. Each Narcan device holds one dose of medication that’s given as a spray into one nostril.

Narcan is given when opioid overdose happens or has possibly happened. For a list of possible symptoms of opioid overdose, see the “What is Narcan used for?” section below.

Keep in mind that each container of Narcan holds a single dose of the medication. If more than one dose is needed, a new container of Narcan must be used for each dose. And the doses should be alternated between the right and left nostrils.

It’s important that 911 or your local emergency number be called as soon as the first dose of Narcan is given. This is necessary, even if the affected person becomes responsive and starts breathing normally after getting Narcan.

For step-by-step guidelines on how to administer Narcan, view the drug’s instructions for use.

Taking Narcan with other drugs

Narcan isn’t given with other medications when it’s administered by caregivers or loved ones. But, when emergency personnel arrive and begin to care for the affected person, they may give other medications with Narcan.

These other medications may include drugs to help with the person’s breathing.

Additionally, if someone’s opioid overdose was due to misuse of opioids, their doctor may recommend other medications be used after treatment with Narcan. (With misuse, a drug is taken in a way that it’s not prescribed or intended to be taken.) In this case, these other medications could help prevent future opioid misuse.

Questions for your doctor

You may have questions about Narcan and your treatment plan. It’s important to discuss all your concerns with your doctor.

Here are a few tips that might help guide your discussion:

  • Before your appointment, write down questions like:
    • How will Narcan affect my body, mood, or lifestyle?
  • Bring someone with you to your appointment if doing so will help you feel more comfortable.
  • If you don’t understand something related to your condition or treatment, ask your doctor to explain it to you.

Remember, your doctor and other healthcare professionals are available to help you. And they want you to get the best care possible. So don’t be afraid to ask questions or offer feedback on your treatment.

Find answers to some commonly asked questions about Narcan.

Can Narcan be given by intramuscular injection or IV?

No, Narcan isn’t given by intramuscular injection (an injection into your muscle) or intravenous (IV) injection (an injection into your vein). Instead, it’s only given as a spray into your nostrils.

If you’re unable to receive a sprayed medication in your nostrils, talk with your doctor. They may be able to recommend treatment options for opioid overdose other than Narcan.

Is Narcan used to treat cocaine or alcohol overdose?

No, it’s not. Narcan only works to help reverse opioid overdose. It doesn’t help reverse overdose that’s due to alcohol or cocaine.

If you or someone you know has an alcohol or cocaine overdose, call 911 or your local emergency number right away. But don’t give Narcan unless the person may also have an opioid overdose.

How does Narcan compare with naltrexone?

Narcan is used for emergency treatment of opioid overdose. Naltrexone, on the other hand, is used for longer-term management of opioid use disorder (OUD), formerly called opioid abuse.

With OUD, opioids are misused. (Misuse happens when a drug is taken in a way that it’s not prescribed or intended to be taken.) Naltrexone is often used together with counseling and behavior therapies for OUD.

To learn more about how Narcan and naltrexone are alike and different, view this article. And talk with your doctor if you have more questions about these two medications.

Narcan is used for emergency treatment of opioid overdose.

It’s an opioid antagonist, which means it works by blocking certain receptors (attachment sites) in your body that opioids bind to.

By blocking these receptors, Narcan helps to reverse symptoms of opioid overdose. For a list of possible symptoms of opioid overdose, see the “What is Narcan used for?” section below.

Once opioid receptors are blocked by Narcan, symptoms of opioid overdose can quickly go away.

But keep in mind, it’s always important to call 911 or your local emergency number anytime Narcan is given. This is necessary even if the person affected becomes responsive and starts breathing normally after getting Narcan.

How fast does Narcan work?

Narcan begins working as soon as it’s been given. In fact, someone may become responsive 2 to 3 minutes after their first dose is given. But sometimes, repeated doses of Narcan are needed.

It’s important that Narcan continue to be given once every 2 to 3 minutes until the person affected becomes responsive and breathes normally or until medical help arrives. Also, do not reuse a Narcan nasal spray device after giving one dose. Use a new nasal spray device for each dose.

How long does Narcan stay in your system?

Narcan can stay in your system for several hours.

The half-life of Narcan is about 2 hours. (Half-life is the time it takes for half of a dose of a medication to be cleared from your body.) It can take 10 hours or so for Narcan to be completely cleared from your body.

Even though Narcan stays in your body for a while, it’s always important to call 911 or your local emergency number after Narcan has been given. This is because other medications or treatments may need to be given with Narcan to fully treat opioid overdose.

If you or someone you know takes an opioid medication, your doctor may suggest that you have Narcan available. (Opioids are medications used for pain.)

Narcan is used in people of all ages if opioid overdose happens or has possibly happened. Narcan is usually given by a caregiver or loved one if they think opioid overdose has occurred.

Narcan treats opioid overdose by blocking certain receptors (attachment sites) in your body that opioids bind to. Blocking these receptors helps to reverse symptoms of opioid overdose. Once the receptors are blocked, the symptoms may quickly improve.

Symptoms of opioid overdose may include:

Your doctor may recommend that you have Narcan available if you take a drug that has an opioid in it. Many pain medications contain opioids, including:

Narcan is approved for use in both children and adults. The use of naloxone (the active drug in Narcan) has been studied in children of all ages, including newborns. But for newborns, certain medications for opioid overdose may be safer than Narcan. If a newborn needs treatment for opioid overdose, their doctor will recommend the best medication for them.

Like most drugs, Narcan may cause mild or serious side effects. The lists below describe some of the more common side effects that Narcan may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you may be taking

Your doctor or pharmacist can tell you more about the potential side effects of Narcan. They can also suggest ways to help reduce side effects. And for more information, you can see this in-depth article.

Mild side effects

Here’s a short list of some of the mild side effects that Narcan can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read Narcan’s prescribing information.

Mild side effects of Narcan that have been reported include:

  • constipation
  • toothache
  • muscle spasms
  • pain in your bones
  • headache
  • dry, stuffy nose, or pain and swelling in your nose

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Narcan can occur, but they aren’t common. If you have serious side effects from Narcan, call your doctor right away. However, if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Narcan that have been reported, and are discussed below in the “Side effect focus” section, include:

* Allergic reaction wasn’t reported in clinical studies of Narcan, but it may still happen.

Side effect focus

Learn more about some of the side effects Narcan may cause.

Opioid withdrawal symptoms

It’s possible to have symptoms of opioid withdrawal after you receive Narcan. (Withdrawal symptoms are side effects that can occur when you stop taking a drug that your body has become dependent on.) Keep in mind that Narcan, which is used for opioid overdose, blocks the effects of opioids in your body.

Symptoms of opioid withdrawal may include:

In infants under 4 weeks old, sudden opioid withdrawal may be life threatening if not treated correctly. Signs and symptoms of opioid withdrawal in babies can include:

  • seizures
  • crying more than usual
  • increased reflexes

What might help

If you have opioid withdrawal symptoms after getting Narcan, tell your doctor. They can recommend ways to manage your symptoms.

If your child is younger than 4 weeks old and they have signs of opioid withdrawal, or they’ve received a dose of Narcan, call your doctor right away or go to the nearest emergency room.

Some at-home remedies that may help with opioid withdrawal symptoms in adults include:

  • increasing your fluid intake to stay hydrated
  • taking hot baths to help alleviate body aches
  • walking or doing other exercises to help with restlessness and irritability
  • doing an activity you enjoy or watching a favorite movie to help distract you from the symptom
Allergic reaction

Some people may have an allergic reaction to Narcan. While allergic reaction wasn’t reported in clinical studies of Narcan, it can still happen.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (warmth, swelling, or discoloration in your skin)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Narcan. But if you think you’re having a medical emergency, call 911 or your local emergency number.

What might help

If you receive Narcan, be sure to stay with a caregiver or loved one until emergency medical staff arrives. Also, 911 or your local emergency number should be called anytime Narcan is given.

Your caregiver or loved one can help watch for any symptoms of an allergic reaction until medical help arrives.

The cost of drugs can vary depending on many factors. These factors include what your insurance plan covers and which pharmacy you use.

Narcan is available as the generic drug naloxone. Generics usually cost less than brand-name drugs. Talk with your doctor if you’d like to know about taking generic naloxone nasal spray.

If you have questions about how to pay for Narcan, talk with your doctor or pharmacist. You can also visit Medicine Assistance Tool to see if they have support options available.

For more information about Narcan’s cost, see this article.

Talk with your doctor about whether you need to have Narcan available. Your doctor will talk with you about certain considerations for using this drug, such as possible interactions and warnings.

These and other considerations are described below.

Interactions

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

There aren’t any known interactions with Narcan and any drugs or supplements. But it’s possible that Narcan could interact with some drugs or supplements.

Before getting Narcan from your pharmacy, be sure to tell your doctor or pharmacist about all medications you take (including prescription and over-the-counter types). Also describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with Narcan.

Warnings

Narcan may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Narcan. Factors to consider include those in the list below.

  • Heart problems. Narcan may cause heart problems, including heart attack. This risk is more common in people who already have heart problems. If you have any heart problems, talk with your doctor to see if Narcan is safe for you.
  • Allergic reaction. If you’ve had an allergic reaction to Narcan, naloxone (the active drug in Narcan) or any of its ingredients, you shouldn’t take Narcan. In fact, the drug is contraindicated (should not be used) in people who’ve had an allergic reaction to it. Ask your doctor what other medications are better options for you.

Use with alcohol

There aren’t any known interactions between Narcan and alcohol.

But, keep in mind that Narcan doesn’t help reverse alcohol overdose. Instead, Narcan only works to help reverse opioid overdose. If you have an alcohol overdose, call 911 or your local emergency number right away.

And be sure to talk with your doctor about any questions you have related to drinking alcohol and using Narcan.

Pregnancy and breastfeeding

It’s not known if Narcan is safe to take while you’re pregnant or breastfeeding.

If it’s used during pregnancy, Narcan may pass to the fetus and cause opioid withdrawal symptoms after the baby is born. (Withdrawal symptoms are side effects that can occur when you stop taking a drug that your body has become dependent on.) If you’ve been given Narcan while pregnant, be sure to discuss this with your doctor so they can monitor the health of the fetus.

If you’re pregnant or breastfeeding, ask your doctor if Narcan is safe for you to take.

It’s important to take medications, including Narcan, exactly how your doctor prescribes them. Using more medication than what’s prescribed can lead to serious side effects.

But keep in mind, there’s no maximum recommended dose for Narcan, which is used for opioid overdose. Instead, Narcan may be given multiple times as needed, every 2 to 3 minutes. The drug should continue to be administered until the person affected becomes responsive and starts breathing normally or medical help arrives.

If you or someone you know takes a medication that contains an opioid, your doctor may suggest that you have Narcan available. (Opioids are medications used for pain.)

Narcan is used for emergency treatment of opioid overdose. For more information about medications that contain opioids, check out this article. And to learn about causes, risk factors, and symptoms of opioid overdose, view this article.

If you have questions about using Narcan while taking an opioid drug, talk with your doctor or pharmacist.

You may want to ask your doctor questions like these:

  • How can side effects of Narcan be reduced?
  • What are possible symptoms of opioid overdose?
  • Are there treatment options besides Narcan that can be used for opioid overdose?

For more information about how to use Narcan and where to get Narcan, visit the drug manufacturer’s site. And to learn more about Narcan, you can also see these articles:

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Q:

Are there any risk factors for opioid overdose?

Anonymous

A:

Yes, there are a variety of risk factors associated with opioid overdose, which Narcan is used to treat.

These risk factors can include:

If you have more questions about risk factors for opioid overdose, talk with your doctor or pharmacist.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.