Opvee (nalmefene) is a brand-name nasal spray that’s prescribed for opioid overdose. As with other drugs, Opvee can cause side effects, such as headache, nausea, or dizziness.

Opvee can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Opvee in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Opvee use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Opvee’s prescribing information.

Mild side effects that have been reported with Opvee include:

  • nausea
  • headache*
  • dizziness
  • hot flashes
  • vomiting
  • anxiety
  • fatigue
  • nasal congestion
  • throat irritation
  • redness or discoloration of the skin
  • decreased appetite
  • sweating
  • nasal discomfort or pain*
  • unusual taste
  • mild allergic reaction†

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect while taking Opvee and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

† An allergic reaction is possible after using Opvee. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

Opvee may cause serious side effects. However, serious side effects from this medication aren’t common. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Opvee’s prescribing information.

If you develop serious side effects while taking Opvee, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

* An allergic reaction is possible after using Opvee. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

Learn more about some of the side effects that Opvee may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Opvee.

Headache

You may develop a headache from Opvee. Headaches were one of the most common side effects people who used Opvee experienced.

What you can do

If you develop a headache after taking Opvee, talk with your doctor. They may be able to recommend ways to manage your headache. For example, they may recommend staying hydrated or taking an over-the-counter medication, such as acetaminophen (Tylenol).

Nasal discomfort and pain

You may experience nasal discomfort or pain from Opvee. This medication is available as a nasal spray. When the device is inserted into your nose and the spray is given, it may cause some discomfort or pain.

Nasal discomfort was a common side effect reported by people who used Opvee.

What you can do

Nasal discomfort or pain from Opvee is short term. You likely won’t need to treat the symptoms. If you have pain that’s severe, your doctor may recommend taking an over-the-counter medication, such as acetaminophen (Tylenol). In most cases, the nasal discomfort or pain will resolve on its own.

Allergic reaction

As with most drugs, Opvee can cause an allergic reaction in some people. However, it’s not clear whether this side effect occurred in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Opvee. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Opvee. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Heart problems: Tell your doctor about any heart problems you have before they prescribe Opvee for you. It’s possible for Opvee to cause opioid withdrawal. In some cases, this may cause a fast heart rate or changes in your blood pressure. So your doctor may recommend more frequent monitoring of your heart.

Allergic reaction: If you’ve had an allergic reaction to Opvee or any of its ingredients, your doctor will likely not prescribe Opvee. Ask your doctor what other medications may be better options for you.

Pregnancy or breastfeeding:If you’re pregnant or breastfeeding your child, Opvee may or may not be safe for you. No studies have been done on the safety of Opvee during pregnancy. However, an opioid overdose can be life threatening to both the pregnant person and the fetus. So experts recommend treating an opioid overdose with a medication such as Opvee.

In addition, animal studies do not show harm to a developing fetus when they are exposed to Opvee during pregnancy. However, animal studies don’t always indicate what may happen in humans.

There are also no studies done on people taking Opvee while breastfeeding. It’s not known if the drug may be present in breast milk or what effects the drug may have on a breastfeeding baby. In animal studies, Opvee is present in breast milk. However, animal studies don’t always indicate what may happen in humans.

You should still talk with your doctor about the possible effects of Opvee while you’re pregnant or breastfeeding.

Alcohol consumption: If you drink alcohol, Opvee is likely safe for you. There aren’t any known interactions between alcohol and Opvee. However, talk with your doctor if you drink alcohol and are taking opioids or if you are prescribed Opvee and have questions about drinking alcohol.

If you’d like to learn more about Opvee, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Opvee: For details about other aspects of Opvee, refer to this article.
  • Dosage: For information about the dosage of Opvee, view this article.

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.