Nalmefene (By injection)

Nalmefene Hydrochloride (NAL-me-feen hye-droe-KLOR-ide)

Treats opioid overdose in an emergency situation. Must be given as soon as possible.

Brand Name(s):

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. You should not receive it if you had an allergic reaction to nalmefene.

How to Use This Medicine:

Injectable

• This medicine is given through a needle placed into one of your veins. It can also be given as a shot under your skin or into a muscle.
• A nurse or other health provider will give you this medicine.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, or heart or blood vessel disease.
• This medicine should be given right away after a suspected or known overdose of an opioid (narcotic) medicine. This will help prevent serious breathing problems that can lead to death.
• The effects of the opioid medicine may last longer than the effects of the nalmefene. This means the breathing problems could come back. Always call for emergency help after the first dose of nalmefene.
• This medicine could cause withdrawal symptoms from the opioid medicine.
• This medicine may cause heart or blood vessel problems (including pulmonary edema, tachycardia, ventricular fibrillation, high or low blood pressure).
• Nalmefene injection may not be able to completely reverse the opioid effects (including respiratory depression) of buprenorphine.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Blue lips and fingernails, chest pain, increased sweating, trouble breathing, swelling in the legs and ankles
• Blurred vision, headache, fast, pounding, or uneven heartbeat
• Lightheadedness, dizziness, fainting

If you notice these less serious side effects, talk with your doctor:

• Fever, chills
• Nausea, vomiting

If you notice other side effects that you think are caused by this medicine, tell your doctor

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

Last Updated: 4/23/2024