Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Zurnai

Descriptions


Nalmefene injection is used for emergency treatment of an opioid overdose or a possible overdose. Some signs and symptoms of an opioid emergency are breathing problems (which can range from slow or shallow breathing to no breathing), extreme sleepiness, or not being able to respond.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Solution

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of nalmefene injection in children younger than 12 years of age. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of nalmefene injection in the elderly. However, elderly patients are more likely to have age-related liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving this medicine.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Heart or blood vessel disease—Use with caution. May make these conditions worse.
  • Kidney disease or
  • Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper Use

This medicine should be given immediately when a suspected or known opioid overdose has occurred. This will help prevent serious breathing problems and severe sleepiness that can lead to death.

Call for emergency help right away after the first dose of this medicine. The reversal effects of nalmefene are temporary. Patients who receive this medicine should be closely monitored.

A home health caregiver or a family member will give you or your child this medicine. It may be given as a shot under your skin or into a muscle of the outer thigh, through clothing if needed. Do not inject into any other area of the body.

This medicine comes with patient information leaflet and patient instructions. Let your home health caregiver or family member read and follow the directions carefully. Ask your doctor if you have any questions.

To use the autoinjector:

  • Do not test or prime the autoinjector before use. This medicine can only be used one time.
  • Check the liquid in the autoinjector. It should be clear, colorless to light-yellow. Do not use this medicine if it is cloudy, discolored, or has particles in it. Do not use it if it is broken or the blue cap is missing.
  • Twist the blue cap counterclockwise to break the safety seal and pull straight off to remove the cap. Do not replace the cap after it has been removed. Do not touch the needle.
  • Place the needle guard against the outer thigh. Push the autoinjector firmly down against the outer thigh until you hear a "click". Hold in place for 3 seconds. The viewing window should turn completely orange (fully blocked). Remove the autoinjector.
  • Move the patient on their side (recovery position) after giving the medicine and get emergency medical help right away.
  • Watch the patient closely. You may also give additional doses to the patient every 2 to 5 minutes until the patient responds or emergency medical assistance becomes available. Give a new nalmefene injection for each dose.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For injection dosage form (autoinjector):
    • For opioid overdose:
      • Adults and children 12 years of age and older—At first, 1.5 milligrams (mg) injected under the skin or into a muscle. Another injection may be given every 2 to 5 minutes until the patient responds or until emergency medical assistance becomes available.
      • Children younger than 12 years of age—Use and dose must be determined by your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions

The effects of the opioid medicine may last longer than the effects of the nalmefene. This means the breathing problems and sleepiness could come back. Always call for emergency help after the first dose of nalmefene.

Severe opioid withdrawal symptoms may happen suddenly after receiving this medicine. These include body aches, a fever, sweating, runny nose, sneezing, goose bumps, yawning, weakness, shivering or trembling, nervousness, restlessness or irritability, diarrhea, nausea or vomiting, stomach cramps, fast heartbeat, and increased blood pressure.

Nalmefene injection may not be able to completely reverse the opioid effects (eg, respiratory depression) of buprenorphine and pentazocine. Repeated doses of nalmefene may be needed to reverse the opioid effects.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Fast, irregular, pounding, or racing heartbeat or pulse

Less common

  1. Blurred vision
  2. confusion
  3. dizziness
  4. dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  5. feeling of warmth
  6. flushing or redness or the skin, especially on the face and neck
  7. headache
  8. nervousness
  9. pounding in the ears
  10. sweating
  11. unusual tiredness or weakness

Rare

  1. Anxiety
  2. body aches or pain
  3. chest pain or discomfort
  4. cough
  5. decrease in frequency of urination
  6. decrease in urine volume
  7. difficulty in passing urine [dribbling]
  8. discouragement
  9. dryness or soreness of the throat
  10. dry mouth
  11. feeling sad or empty
  12. fever
  13. hoarseness
  14. hyperventilation
  15. irritability
  16. lack of appetite
  17. loss of interest or pleasure
  18. muscle twitching or jerking
  19. painful urination
  20. rhythmic movement of the muscles
  21. shakiness in the legs, arms, hands, or feet
  22. shaking
  23. sleepiness or unusual drowsiness
  24. slow or irregular heartbeat
  25. stuffy or runny nose
  26. tender, swollen glands in the neck
  27. trembling or shaking of the hands or feet
  28. trouble breathing
  29. trouble concentrating
  30. trouble in swallowing
  31. trouble sleeping
  32. voice changes

Incidence not known

  1. Blue lips and fingernails
  2. coughing that sometimes produces a pink frothy sputum
  3. diarrhea
  4. goosebumps
  5. loss of bladder control
  6. muscle spasm
  7. no blood pressure or pulse
  8. pale skin
  9. shiver
  10. stomach cramps
  11. stopping of the heart
  12. sudden loss of consciousness
  13. swelling in the legs and ankles
  14. yawning

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Burning sensation
  2. continuing ringing or buzzing or other unexplained noise in the ears
  3. hearing loss
  4. redness of the face, neck, arms and occasionally, upper chest

Rare

  1. Itching skin

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Portions of this document last updated: Oct. 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/nalmefene-injection-route/side-effects/drg-20572479