Of all the consequences of the nation’s opioid epidemic — which last year killed 33,091 people, or one overdose death every 15 minutes — the strangest may be how it has increased the abuse of dogs.

Addicts discovered that the painkiller tramadol, prescribed by veterinarians across the country for pets with arthritis or other debilitating ailments, is the same drug prescribed to human cancer patients to dull their pain.

And compared to the more widely abused opioid oxycodone, which can cost up to $10 for a 10-milligram pill, tramadol is dirt-cheap. It wholesales for less than $25 for a 1,000-pill bottle.

Its inexpensive price has already made it a scourge throughout the Third World — and now the problem is moving into developed countries.

In Northern Ireland on Wednesday, one coroner said more teens there now die from tramadol than from morphine or heroin.

Here in the US, opioid abusers are finding veterinarians can be easily fooled into prescribing the drug — even if it means, at times, purposely maiming or abusing their dog to pull off the ruse.

“They’ve gotten very sophisticated in how they obtain drugs and go about their activities,” said Jim Arnold, chief of policy and liaison for the diversion control division at the Drug Enforcement Administration.

Late last year, in a raid outside Portland, Ore., cops seized 100,000 tramadol pills and rescued 17 dogs living in conditions so squalid, there were dead rats in their drinking water.

The cops arrested four people who claimed to be breeding AKC-registered puppies but who they suspect were running a thinly disguised opioid distribution ring.

“My hunch is they got into tramadol through having the dogs,” said Deputy Micah Hibpshman of the Clackamas County Police Department’s narcotics task force. “But so far they haven’t been willing to talk.”

If Hibpshman’s hunch is correct, the case would likely be the largest ever to involve tramadol and dogs.

More normally, cases of tramadol and canine abuse are much more small-time — but equally disgusting.

Heather D. Pereira of Hardin County, Ky., was arrested and charged with using a disposable razor to slice open the leg of her 4-year-old retriever on two separate occasions to get her hands on tramadol.

Chad Bailey, the vet who used six to eight stitches to close Pereira’s dog’s initial wounds, told The Post he became suspicious when she returned to his clinic three days after the first visit for more pills — claiming her child accidentally flushed them down the toilet. Pereira, 23, has no kids.

When she came back soon for a third visit, Bailey had his guard up. He noticed the dog’s wounds were too clean (“not the sort of cuts you see in nature,” he said). As Pereira waited in his clinic, Bailey called the cops. She was convicted of trying to obtain controlled substances by fraud.

“What’s scary is it took me two times to pick up on what was happening,” Bailey told The Post. “It worries me about the instances we miss.”

The DEA’s Arnold appreciates the degree to which vets like Bailey rely on a pet’s owner to explain an animal’s need for medication.

“It’s an area that allows drug seekers to fly under the radar,” he said. “We know it’s happening, but I wouldn’t be surprised if there’s a lot more activity than we’re aware of.”

Veterinarians across the country are beginning to discuss this alarming trend of addicts visiting several locations before they discover an easy mark.

Vet-specific bulletin boards and chat rooms are full of chatter about “doggy doctor shopping” — as the practice of searching out gullible vets is known.

In Plainfield, Ill., a 90-minute drive west of Chicago, two vets meet and the talk gravitates to the problem of tramadol. One recounts how a client was overly skilled at the my-dog-needs-more-tramadol game, according to one chat room conversation.

First the airline lost the dog’s drugs on a trip to Canada, then an extended trip to assist her mom through chemo required an early script renewal for her traveling pet, the vet explained.

That’s when it dawned on the second vet that the same person was pulling the scam on her.

“She’s been using two different pharmacies with our scripts, and two others with my friend’s scripts,” the vet wrote.

In Portland, Ore., co-owners of a pet didn’t let the fact that their dog had been euthanized stop them from going back to their vet for more tramadol, a vet posted on the bulletin board. The co-owners had already filled two tramadol prescriptions and were “trying to fill a third (120 tablets each)” when they were caught, the vet wrote.

Tramadol, with the brand name Ultram, was developed in Germany as a pain reliever for human consumption. Research then established it worked on pets, making it one of very few medicines appropriate for both groups without a formula change.

The drug wasn’t classified by the Food and Drug Administration on its US debut in 1995, despite its history of being abused by humans in Africa, Asia, Eastern Europe and the Middle East.

But in 2010, after studies compared a tramadol high to those of heroin and oxycodone, Uncle Sam began to take notice of the drug’s downside. While not as powerful as oxycodone, tramadol, as an opioid, drives up the body’s production of dopamine. That year, the Department of Health and Human Services reviewed the drug and recommended that tramadol be considered a controlled substance.

In August 2014, the DEA designated tramadol a Schedule IV substance. It’s up to each state to adopt rules on tracking the drug’s sales — and some are stricter than others.

In New Jersey, for example, vets aren’t required to report dispensing a controlled substance. In California, however, vets must make a log note of every narcotic they supply. New York requires vets to make an online report within 24 hours of dispensing any tramadol, making its oversight system one of the country’s most stringent.

But the DEA seldom gets involved, Arnold admitted, unless it receives a complaint of abuse or gets wind of extremely large tramadol orders.

“There’s little we can do to confirm if clients have been to another veterinarian to purchase drugs,” said Ronald Stone, who runs the Veterinary Medical and Trauma Center in Groveland, Fla. “We just have to be vigilant.”

With tramadol costing up to 20 times less than oxycodone, DrugAbuse.com is warning that it “may become the new opioid of choice for abusers.”

For a couple in Ashland, Ohio, it already has.

Before they took their bulldog to the city’s Claremont Veterinary Clinic last July, the vet on duty there was tipped by nearby clinics that the pet’s co-owners might be doggy-doctor shopping.

Dr. Kristine LaFever, who later learned the dog had been shuttled to up to four pet hospitals that day, sensed the tip was true when the co-owners came into her clinic and asked for tramadol by name.

“They didn’t want to take the drugs I wanted to give the dog, which irritated me more than anything,” the vet said.

LaFever refused the pet’s owners, ages 20 and 21, sending them away empty-handed. But the couple’s rage over being denied tramadol, she said, left her feeling “sure for the first time” that she had thwarted an exercise in doggy-doctor shopping.

A week or so later, her dad, also a vet, arrived for work at the same clinic — only to find its safe pried open and its inventory of tramadol and phenobarbital stolen.

The dad, Donald Kaeser, also noticed some smatterings of blood, after the culprits cut themselves while entering the clinic through a broken window.

DNA from the blood led police to the couple — one of whom was sentenced last month to two years in prison and one who was placed under house arrest for 120 days.

The clinic, however, has yet to replace the tramadol.

“We’ve gone to not carrying it,” Kaeser said. “If we think a pet needs it, we’ll just call in a prescription.”