Opvee is a brand-name nasal spray that’s prescribed for opioid overdose. Opvee contains the active drug nalmefene.

Opvee is FDA approved as an emergency treatment for opioid overdose in adults and children ages 12 years and older.

Drug details

You’ll find key information about Opvee below.

  • Drug class: opioid antagonists, also called opioid blockers
  • Drug form: nasal spray
  • Generic available? No
  • Prescription required? Yes
  • Controlled substance? No
  • Year of FDA approval: The FDA approved Opvee in 2023.

Note: Opvee is approved, but it’s not available yet. The drug’s manufacturer expects Opvee to be available in late 2023. For more information, talk with your doctor or pharmacist.

Opvee will only be available as a brand-name medication. It’s not available as a generic drug.

A generic drug is an exact copy of the active drug in a brand-name medication. Generics usually cost less than brand-name drugs.

Here are answers to some frequently asked questions about Opvee.

Is Opvee similar to Narcan?

Yes. Opvee and Narcan are both opioid antagonists* used to treat opioid overdose in an emergency. Both medications come as nasal sprays, but they contain different active ingredients. Opvee contains nalmefene. Narcan contains naloxone.

The key difference between these drugs lies in how long they work: A dose of Opvee nasal spray keeps working in the body longer than a dose of Narcan. This is because Opvee’s half-life† is 11.4 hours and Narcan’s half-life is 1–2 hours. Opvee’s long half-life is particularly useful when someone experiences an overdose of opioids with long-lasting effects, such as fentanyl (Fentora, Actiq).

Another difference is that in March 2023, the Food and Drug Administration (FDA) approved Narcan nasal spray as an over-the-counter drug. This means you’ll be able to purchase Narcan without a prescription. Opvee requires a prescription.

Talk with your doctor or pharmacist if you’d like more information about how Opvee and Narcan compare.

* An antagonist blocks the effects of the drug in your body. Opioid antagonists block the effects of opioids, so they are also known as opioid blockers.
† A drug’s half-life is the amount of time it takes for the body to clear half of one dose of the drug.

How does Opvee work? And how long does the drug take to start working?

With an opioid overdose, someone takes more opioid than their body can process. Opvee treatment stops the life threatening effects of an overdose. These effects may include respiratory depression (slow or no breathing) and central nervous system (CNS) depression. Symptoms of CNS depression include excessive drowsiness and loss of consciousness.

Opvee works by blocking opioid receptors (binding sites) in the body. By blocking these receptors, opioid drugs cannot bind to them. This reverses the effects of opioids, including overdose symptoms.

Opvee starts working to restore breathing within 2–5 minutes. The drug’s full effects may take up to 15 minutes.

Immediately after administering Opvee nasal spray to someone, call 911 or your local emergency number. Stay with the person while you’re waiting for help to arrive. If the person isn’t breathing as usual or become responsive within 2–5 minutes, you can administer another dose of Opvee. (For more information about how to give Opvee, see the “Opvee dosage” section below.)

Is Opvee safe for older adults?

Opvee should be safe for older adults (people ages 65 years and older).

Clinical trials of Opvee didn’t include adults ages 65 years and older. However, previous reports of the drug’s use in older adults didn’t show any differences in safety or effectiveness compared to adults less than 65 years.

Older adults are generally more sensitive to the effects of drugs including Opvee. This is due to changes in the body that occur with age. But keep in mind that an opioid overdose can be life threatening. So the benefits of treating an opioid overdose outweigh any risks of Opvee in older adults. (Opvee is an emergency treatment for opioid overdose.)

If you have questions about this, talk with your doctor or pharmacist for more information. To learn about side effects of Opvee, see the “Opvee side effects” section below.

The following information describes the recommended dosage of Opvee.

Drug forms and strengths

Opvee is a nasal spray. It comes as a liquid solution that contains 2.7 milligrams (mg) of nalmefene (the active drug in Opvee).

Opvee comes in a two-pack — a box that contains two separate nasal spray devices. Each device contains one spray (a single dose).

If someone experiences an opioid overdose, they won’t be able to self-administer Opvee. It’s meant to be administered by someone else.

Dosage and administration for opioid overdose

The dosage of Opvee for a known or suspected opioid overdose is one spray (2.7 mg) into one nostril.

To administer Opvee, gently tilt the person’s head back while supporting their neck. Then insert the plunger of the nasal spray device into the person’s nose. Press the plunger firmly until it stops.

Immediately after administering Opvee nasal spray, call 911. Stay with the person while you’re waiting for medical help to arrive. If the person’s breathing doesn’t improve within 2–5 minutes, you can give another dose of Opvee in the other nostril. You’ll need to open a new Opvee nasal spray device for each dose. (Each device contains only one dose.)

If needed, you can continue to give doses of Opvee every 2–5 minutes until the ambulance arrives.

For detailed directions on giving Opvee, see the “Instructions for use” section of the drug’s prescribing information.

Children’s dosage

Opvee is given as an emergency treatment for opioid overdose in adults and children ages 12 years and older. The dosage of Opvee for children and adults is the same. See “Dosage and administration for opioid overdose” just above for details.

Opvee overdose

Opvee is given as an emergency treatment for a known or suspected opioid overdose. You won’t harm someone by giving them Opvee, even if you’re not sure whether they overdosed on opioids. Also, you cannot harm someone by giving them any amount of Opvee.

That said, if you’re concerned about an overdose of Opvee, call your doctor. You can also call America’s Poison Centers at 800-222-1222 or use its online tool.

Opvee can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Opvee. These lists do not include all possible side effects.

For more information about the possible side effects of Opvee, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be concerning or bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to notify the FDA about a side effect you’ve had with Opvee, you can do so through MedWatch.

Mild side effects

Below is a partial list of mild side effects of Opvee. To learn about other mild side effects, talk with your doctor or pharmacist, or view Opvee’s prescribing information.

Mild side effects of Opvee can include:

Most of these side effects may go away within a few days to a couple of weeks. However, if they become more severe or don’t go away, talk with your doctor or pharmacist.

* For more information about allergic reaction and Opvee, see “Allergic reaction” below.

Serious side effects

Serious side effects from Opvee aren’t common, but they can occur.

Always call 911 or your local emergency number after administering an Opvee dose. Call for help even after the person wakes up or their breathing improves.

Serious side effects and their symptoms can include:

* With dependence, your body needs the drug to feel like you usually do. Opvee works by reversing the effects of opioids caused by an overdose. This reduces your body’s exposure to the opioid, which may result in opioid withdrawal. To learn more, see “How does Opvee work? And how long does the drug take to start working?” in the “Common questions about Opvee” section above.
† For details about allergic reaction and Opvee, see “Allergic reaction” below.

ALLERGIC REACTION

As with most drugs, some people can have an allergic reaction after taking Opvee. This side effect wasn’t reported in clinical trials of this drug but can still occur.

Symptoms of a mild allergic reaction can include:

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
  • swelling of your tongue, mouth, or throat
  • trouble breathing

Call your doctor right away if you have an allergic reaction to Opvee, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency

As with all medications, the cost of Opvee can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

To learn more about saving money on prescriptions, check out this article.

Generic version: Opvee is not available as a generic version. A generic drug is an exact copy of the active drug in a brand-name medication. Generics tend to cost less than brand-name drugs.

The Food and Drug Administration (FDA) approves prescription drugs such as Opvee to treat certain conditions. Opvee may also be used off-label for other conditions. Off-label drug use is when an FDA-approved drug is prescribed for a purpose other than what it’s approved for.

Opvee for opioid overdose

Opvee is FDA approved for the emergency treatment of a known or suspected opioid overdose in adults and children ages 12 years and older.

Opioids are a group of drugs. Examples of opioids include heroin and prescription pain medications such as fentanyl (Fentora, Actiq) and oxycodone (Roxicodone, Oxycontin, others).

An overdose occurs when someone takes more opioids than their body can process. This results in life threatening effects, including respiratory depression (slow or no breathing) and central nervous system (CNS) depression. Symptoms of CNS depression include excessive drowsiness and loss of consciousness.

To learn how Opvee works, see “How does Opvee work? And how long does the drug take to start working?” in the “Common questions about Opvee” section above.

Note: Opvee is not a substitute for emergency medical care. Always call 911 or your local emergency number immediately after administering Opvee to someone. For details, see “Dosage and administration for opioid overdose” in the “Opvee dosage” section above.

Opvee and children

Opvee is FDA approved for the emergency treatment of opioid overdose in children ages 12 years and older. It isn’t known if the drug is safe or effective in children younger than 12 years old.

Opvee is not known to interact with other medications, herbs, supplements, foods, or alcohol. The manufacturer did not list any interactions in the drug’s prescribing information.

However, this doesn’t mean that interactions won’t be recognized in the future. For example, new drugs could be approved that interact with Opvee.

When you receive an Opvee prescription, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you take. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Other drugs are available that can treat an opioid overdose. If you’re interested in finding an alternative to Opvee, talk with your doctor. They can tell you about other medications that may be an option for you.

The following drugs are similar to Opvee:

  • naloxone nasal spray (Narcan, Kloxxado, Rextovy)
  • naloxone injection (Zimhi)

Note: Opvee was approved by the FDA but it’s not available yet. The drug’s manufacturer expects Opvee to be available in late 2023. For more information, talk with your doctor or pharmacist.

If you can become pregnant, consider the following information about pregnancy and breastfeeding.

Opvee and pregnancy

It’s not known whether Opvee is safe for use during pregnancy.

However, an opioid overdose can be fatal to the pregnant person and their fetus. So the benefits of treating an opioid overdose outweigh any potential risks of Opvee use during pregnancy. (Opvee is an emergency treatment for opioid overdose.) To learn about the risks of opioid use during pregnancy, see this article.

If you think someone may be having an opioid overdose, administer Opvee as soon as possible. You cannot harm someone by giving them Opvee. For details, see “Dosage and administration for opioid overdose” in the “Opvee dosage” section above.

If you have questions about Opvee treatment during pregnancy, talk with your doctor for more information.

Opvee and breastfeeding

It’s not known whether Opvee should be given to someone who is breastfeeding a child.

But keep in mind an opioid overdose can be life threatening. So the benefits of treating an opioid overdose outweigh any potential risks in this situation. If you think someone may be experiencing an opioid overdose, administer Opvee as soon as possible. You cannot harm someone by giving them Opvee.

If you’d like more information about this, talk with your doctor or pharmacist.

Before taking Opvee, discuss your health history with your doctor. They may not prescribe Opvee if you’ve previously had an allergic reaction to any of its ingredients.

Note: For more information about the potential negative effects of Opvee, see the “Opvee side effects” section above.

Disclaimer: Medical News Today 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.