Key takeaway
Someone may be overdosing, and the spray you have might be nalmefene rather than naloxone. FDA approved Opvee, a prescription nasal spray, on May 22, 2023, for people age 12 and older. If they will not wake or are not breathing, call 911, use the product you have, and stay.
Last updated: Mon Oct 05 2026 00:00:00 GMT+0000 (Coordinated Universal Time)
Someone will not wake, and the spray in the bag might not be the naloxone you have heard called Narcan. Using the wrong name is a small problem. Waiting to sort the names while they are not breathing is the dangerous one.
If they will not wake or are not breathing, call 911, use the reversal product you have, and stay. For a mental health crisis, call or text 988.
Read the box, then stay
On May 22, 2023, the FDA approved Opvee, a prescription nalmefene nasal spray, for known or suspected opioid overdose in adults and in children age 12 and older. The spray delivers 2.7 milligrams into the nose. It is for health care and community settings. It is not for sale over the counter, and it is not a substitute for emergency care.
NIDA groups naloxone products as Narcan, Kloxxado, Zimhi, and ReVive, and it names Opvee as the nalmefene spray. Two naloxone nasal sprays are available without a prescription. If the box says nalmefene or Opvee, it is this medicine. If it says naloxone, match it to signs and naloxone. Given quickly, nalmefene can reverse slowed breathing, sedation, and low blood pressure from an opioid. Follow the instructions on the product you were given, and follow the dispatcher if those instructions differ.
SAMHSA tells bystanders to start CPR if breathing has stopped or is very weak and someone trained can do it, and to give naloxone or nalmefene if it is available. Many opioids outlast a reversal dose, so the person can become sleepy again. Stay. The FDA announcement does not print a minute count for how long Opvee lasts, so do not borrow one from a naloxone label.
What else might be in the bag
Nalmefene does not reverse xylazine. Give the opioid reversal medicine anyway, because xylazine in the illegal supply is usually mixed with fentanyl or another opioid. The sedative can keep working after the opioid effect is reversed. Read xylazine and fentanyl when that sedative may be in the bag. More than one drug changes what you see. Nalmefene will not restart breathing that stopped from alcohol or a benzodiazepine alone. Those emergencies still need the ambulance. A small amount of fentanyl can stop breathing, which fentanyl treatment explains, and that supply problem is not a reason to skip the spray.
In someone who is dependent on opioids, the medicine can precipitate withdrawal. That reaction is miserable. It is still not the emergency you are in when breathing has stopped. Do not delay the spray to avoid it.
After they are breathing
Nalmefene does not treat opioid use disorder. Methadone, buprenorphine, and naltrexone are the medicines for the disorder. A spray in a bag does not replace one of those prescriptions, and a prescription does not mean you skip carrying a reversal product. After the ambulance, ask about opioid care.
FindTreatment.gov lists licensed programs. Good Samaritan laws vary by state. The legal fear can wait until they are breathing. Call or text (800) 653-9376 if you want help finding treatment after the emergency, or if you are trying to tell a reversal spray from a medicine for opioid use disorder.
Additional Resources
Sources cited on this page:
- FDA: FDA approves prescription nasal spray to reverse opioid overdose (May 22, 2023)
- NIDA: Overdose reversal medications
- NIDA: Xylazine
- NIDA: Fentanyl
- SAMHSA: Opioid overdose prevention and reversal
- SAMHSA FindTreatment.gov
- 988 Suicide & Crisis Lifeline
Common Questions
Is nalmefene the same thing as Narcan?
No. NIDA lists them as different overdose-reversal medicines. Naloxone products include Narcan, Kloxxado, Zimhi, and ReVive. Nalmefene's nasal spray is Opvee. Two naloxone nasal sprays are available without a prescription. Opvee is a prescription product. Read the signs-and-naloxone guide when the box says naloxone.
Who is Opvee approved for?
FDA says it is for the emergency treatment of known or suspected opioid overdose in adults and in children age 12 and older, when breathing or the central nervous system is depressed. The spray delivers 2.7 milligrams into the nose. It is meant for health care and community settings. It is not a substitute for emergency medical care. Follow the instructions on the product you were given.
Can it cause withdrawal?
Yes, in someone who is opioid-dependent. FDA lists body aches, diarrhea, a fast heart rate, fever, a runny nose, sneezing, goosebumps, sweating, yawning, nausea or vomiting, nervousness, restlessness or irritability, shivering or trembling, stomach cramps, weakness, and higher blood pressure. That misery is not a reason to withhold the medicine when someone is not breathing.
Does nalmefene reverse xylazine or treat addiction?
It does not reverse xylazine. Give it anyway if an opioid may be mixed in, which is common, and call 911 because the sedative can continue after the opioid effect is reversed. Nalmefene is also not methadone, buprenorphine, or naltrexone. Those medicines treat opioid use disorder. A reversal spray treats the emergency in front of you.
How common were fatal overdoses when Opvee was approved?
FDA's May 22, 2023 announcement said more than 103,000 fatal overdoses were reported in the 12 months ending November 2022, driven primarily by synthetic opioids such as illegally made fentanyl. That figure belongs to that announcement. It is not a local count for this month. NIDA says currently approved reversal medicines, including nalmefene, are approved for overdoses caused by opioids like fentanyl.