Naloxone: what it treats, how to use it, side effects
Last updated September 3, 2026.
Naloxone nasal spray is the opioid-overdose rescue: it blocks opioid effects and can restart breathing within minutes. You may know it as Narcan. It is available over the counter - no prescription needed - and it is designed for bystanders: family, friends, and strangers, not medics.
What does it treat?
Known or suspected opioid overdose, in adults and children, alongside emergency medical treatment. The overdose picture: excessive sleepiness, no response to a loud voice or a firm rub on the chest, shallow or stopped breathing, small pupils.
How do you use it?
The sequence: spray one dose into one nostril - no priming, no aiming skill needed - call 911 immediately after the first dose, turn the person on their side (recovery position), and stay with them. If they do not wake, respond, or breathe normally - or they improve and then relapse - give another dose with a new spray in the other nostril every 2 to 3 minutes until help arrives. Each device is single-use. Learn the steps before you need them: your pharmacist will show you, and anyone who spends time around someone at risk should know where the spray is and how to use it. Keep it available at all times and replace it when it expires.
Side effects to know
- Expected - withdrawal, not harm: in someone opioid-dependent, naloxone triggers sudden withdrawal: body aches, diarrhea, racing or irregular heartbeat, fever, runny nose, sneezing, sweating, yawning, nausea, vomiting, nervousness, restlessness, irritability, shivering, trembling, stomach cramps, weakness, goosebumps. Miserable, and worth it - breathing beats comfort.
- Serious - get emergency treatment: seizures and loss of consciousness. In babies treated with naloxone: crying more than usual and stronger-than-normal reflexes.
Who should not use it?
There is essentially no wrong patient in an overdose: it does nothing to a person without opioids aboard, so when in doubt, spray. It is not a substitute for 911 - it buys minutes, and the overdose can return when the dose wears off, which is why the second spray and the ambulance both matter.
When is it an emergency?
The overdose itself is the emergency: spray first, 911 immediately, stay until help arrives. For guidance on storage, replacement, or training, your pharmacist is the fastest resource. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
How do I know if it is an opioid overdose?
The picture: someone who cannot be woken by shouting or a firm rub on the middle of the chest, breathing that is shallow, slow, or stopped, and pupils shrunk to pinpoints - often with blue or gray lips and fingertips. When the picture fits, spray first and call 911 immediately. If you are wrong and it was not opioids, naloxone does no harm - the asymmetric risk is why "when in doubt, spray" is the rule.
Do I really need to call 911 if the naloxone works?
Yes - always. Naloxone wears off in 30 to 90 minutes, and many opioids outlast it: the person can slip back into overdose after looking recovered. The medication buys time for the ambulance; it does not replace it. So the sequence is fixed: first spray, then 911 immediately, then stay and watch until help arrives, redosing every 2 to 3 minutes with a new spray if they fade.
Where do I get naloxone, and do I need a prescription?
No prescription needed - it is sold over the counter at pharmacies, and community programs often provide it free. Keep it where a bystander would think to look, tell your household where it lives, and track the expiry date. If someone in your life takes opioids - prescribed or otherwise - having it nearby is the standard of care, not a judgment about them.
Will I get in trouble for helping someone overdosing?
Most places have Good Samaritan laws protecting people who call for help during an overdose - and naloxone itself is legal to carry and use. The calculus is simple: a reversible death versus a legal worry that is usually covered. Spray, call 911, stay. The details vary by state, but the direction of the law is protection for helpers.
Why does the person sometimes wake up angry or sick?
Precipitated withdrawal: naloxone evicts opioids from their receptors all at once - in a dependent person that means instant, full-force withdrawal: aches, vomiting, sweating, racing heart, misery, and sometimes aggression. It is not an allergic reaction and not a reason to withhold the next dose. Explain what is happening, keep them safe, and let the medics take over - breathing was the goal, and it was met.
Does naloxone expire, and how should I store it?
Yes - each device has an expiry date, and an expired spray may underdose a rescue. Store at room temperature, out of extreme heat and cold - the glove box in August is a bad home. Check the date when you check your smoke alarms, and replace expired devices. The pharmacy will take the old one.