Narcan Isn’t Just for Humans. Here is What Every Vet Needs to Know

Dogs overdose on opioids. Here is what every vet needs their clients to know.

The opioid crisis is not staying outside. It is walking through your door on a leash.

The client who comes in with a lethargic, unresponsive dog may not tell you there are opioids in the house. They may not know their dog got into anything. They may not connect what they are seeing to what you are seeing. And by the time the pieces come together, you are already managing a crisis that could have been reversed in minutes with a medication that costs next to nothing and sits on the shelf at most pharmacies.

Opioid toxicity in dogs is not a theoretical risk. It is an underreported, underdiscussed emergency that is becoming more likely as fentanyl and carfentanyl saturate both the regulated and unregulated drug supply in North America.

Here is what the numbers look like.

The scale of the problem

In the United States, opioid overdose deaths have exceeded 500,000 since 1999, with more than 80,000 deaths recorded in 2023 alone according to the CDC. Synthetic opioids, primarily illicit fentanyl, now account for the vast majority of those deaths. Approximately 6.1 percent of Americans are currently prescribed an opioid, and the unregulated supply has made accidental exposure increasingly common for anyone — or any animal — sharing a living space with someone who uses.

In Canada, the numbers tell a similar story. From 2016 to 2024, there were more than 53,000 reported opioid toxicity deaths nationwide, with fentanyl and carfentanyl driving the surge. Roughly one in ten Canadian households includes someone prescribed an opioid.

More opioids in more homes means more opportunities for dogs to encounter them. Dogs are particularly vulnerable not because of breed or size alone but because of how they navigate the world. They sniff. They lick. They investigate powder on the floor, a dropped pill, a used patch in a trash can. Fentanyl in powder or crystal form — the most common illicit exposure formulation reported to North American veterinary poison control centers between 2019 and 2023 — is exactly the kind of thing a dog finds before anyone realizes it was accessible.

What it looks like when it is happening

Slow or absent breathing is the most critical sign of opioid overdose in dogs and the one that tells you how urgent the situation is. It may arrive alongside extreme lethargy, a blank stare, unconsciousness, unresponsiveness, pale gums, pinpoint pupils, and vomiting.

The same rule that applies in human overdose response applies here: do not wait for every sign to be present before acting. If breathing is compromised and there is any possibility of opioid exposure, treat it as opioid toxicity.

Naloxone works in dogs

Naloxone is used off-label in dogs, meaning it is not formally approved for companion animal use in either the US or Canada, but it is routinely administered in veterinary settings and increasingly by first responders working with police K9 units. A 2023 study on working dogs administered fentanyl found that naloxone was effective in reversing sedation via both intramuscular and intranasal routes.

The practical administration is straightforward. Intranasal: hold the snout closed, spray into one nostril, cover the nose with a towel immediately to reduce the chance of the dog sneezing opioid residue back into the air. Intramuscular: inject into the front portion of the upper thigh muscle. Wear gloves. Do not perform mouth-to-snout resuscitation without a breathing barrier. Wash hands and face thoroughly after contact regardless of whether you think you touched anything.

Expect to give more than one dose. Fentanyl's potency often requires multiple administrations at two to three minute intervals. And critically: naloxone clears the dog's system faster than most opioids, which means symptoms can return 30 to 90 minutes after initial improvement. The dog needs veterinary care even if they look like they have recovered.

In the US, naloxone is available over the counter at most major pharmacy chains and without a prescription in all 50 states as of 2023. NARCAN nasal spray and its generics are widely stocked. The barrier is not access. The barrier is awareness.

The conversation your clients are not having

This is not just a conversation for clients who use opioids. It is a conversation for clients who live with someone who does, clients who have elderly relatives visiting with prescriptions, clients who live in areas where illicit opioid exposure is common, and clients who simply walk their dogs in parks where contaminated surfaces are a real possibility.

The Pet Poison Helpline and the ASPCA Animal Poison Control Center both field opioid exposure calls around the clock. Remind your clients those resources exist. Remind them that calling does not require explaining how the exposure happened.

For veterinary professionals, the clinical priority is getting the history you need without making the client feel like they are being investigated. The dog on your table needs naloxone. The why can come second.

What to tell your clients before it becomes an emergency

Store all medications — human and pet — where dogs cannot access them. Learn the signs of opioid toxicity so you are not searching your phone while your dog is going down. Know where to get naloxone in your area and keep it accessible if there is any opioid in your household. Call your vet or a poison control hotline immediately if you suspect exposure, and bring the dog in even if they seem to be improving.

The opioid crisis has a veterinary chapter. It is time the profession started writing it out loud.

Sources: CDC, Health Canada, North American Veterinary Poison Control Centre, The Conversation/University of Saskatchewan