Nalmefene (Injection)Nalmefene (NAL-me-feen)Helps reverse the effects of certain opioid (narcotic) medicines. The manufacturer stopped making this medicine on June 30, 2008.Brand Name(s): There may be other brand names for this medicine.When This Medicine Should Not Be Used: You should not receive this medicine if you have had an allergic reaction to nalmefene.How to Use This Medicine: Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given through a needle placed in one of your veins. A nurse or other trained health professional 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. Make sure your doctor knows if you are also using flumazenil.Warnings While Using This Medicine: Make sure your doctor knows if you are pregnant or breastfeeding, or if you have heart disease, liver disease, or kidney disease.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. Diarrhea or severe stomach pain. Dizziness, drowsiness, or confusion. Fast or uneven heartbeat. Fever, chills, or sore throat. Lightheadedness or fainting. Twitching or muscle cramps.If you notice these less serious side effects, talk with your doctor: Anxiety or depression. Dry mouth, nausea, or vomiting. Headache or joint pains. Increased sweating. Last Updated: 6/12/2013