Cats attracted to ADHD drug, a feline poison

But it's far from the only human medicine that imperils companion animals in the United States.

SALT LAKE CITY Since 2004, drugs designed for use by people have been the leading source of poisonings among companion animals, according to the national Animal Poison Control Center in Urbana, Ill. And among cats, Adderall – a combination of mixed amphetamine salts used to treat attention deficit hyperactivity disorder – has quickly risen to become one of the most common and dangerous of these pharmaceutical threats.

Or so reported Aiyasami Salem Sreenivasan of the poison control center and his colleagues, this week, here at the Society of Toxicology annual meeting.

In the United States, Adderall is currently “the most widely prescribed medicine for ADHD in children, with almost 23 percent market share,” Salem Sreenivasan notes. This probably explains, he says, why the incidence of accidental consumption by pets has also been steadily rising.

But what really sets this drug apart as a veterinary risk is that unlike most human meds, Adderall apparently appeals to the finicky feline palate, explains Sharon Gwaltney-Brant, a board certified veterinary toxicologist who encountered the problem while working at the poison control center. She and Salem Sreenivasan described 152 cases of feline intoxication with the drug that had been called into the center between January 2002 and June 2009. Almost 80 percent of these involved Adderall XR, the drug’s extended release formulation.

That number may not sound that high, but Gwaltney-Brant points out that this is the tip of the proverbial iceberg because “we are won’t hear about all of the cases.”

Once part of the University of Illinois, the center’s round-the-clock poison hotline is now run by the American Society for the Prevention of Cruelty to Animals. It learns about intoxications when vets call into the crisis center to inquire about any risks posed by ingestion of a particular substance – and, when it’s a poison, how to treat it.

Most poisonings cases that the ASPCA’s center learns about involve dogs, Gwaltney-Brant says, because they’re fairly indiscriminate about what they’ll eat. Not cats. Out of curiosity, they might sample a pill or capsule – but seldom finish it, she says. As soon as they bite in and discover its bland or even objectionable flavor, they tend to walk away.

Except when it comes to Adderall XR. Cats not only bite in but readily finish every bit. This suggests, she says, that there’s something about it that cats find unusually enticing.

And that’s bad, because a single 20 milligram capsule could kill the average size cat.

Why would doctors provide amphetamines – uppers, in the vernacular – to help settle down hyperactive kids? It does sound a bit counterintuitive, Gwaltney-Brant acknowledges. But at low doses, at least in animals, these central-nervous-system stimulants can actually have a calming effect, she notes. Unfortunately, the amounts prescribed to people – even youngsters – do not constitute low doses for a 7- to 15-pound puss.

Owners may initially discover a cat’s intoxication by its distressed vocalizing. Then they may pick up on its anxiety, agitation, pacing, disorientation – even tremors. Cats can quickly become overheated and unusually disturbed by any type of sensory stimulation – sound, light, even physical touch. Vets will typically notice the poisoned pet’s excessively rapid heart rate and elevated blood pressure.

With quick, aggressive treatment, many cats recover, Salem Sreenivasan says. If an owner calls in the problem before symptoms develop (usually that means within 30 minutes), he or she will be instructed to induce vomiting to bring up the drug. “And then take the cat to the vet,” he says, because with the extended release formulation, controlled-release beads in each capsule could elicit a second wave of intoxication within several hours. In some cases, a vet will administer activated carbon to sop up and hold the drug until it’s excreted. And this treatment may need to be repeated if significant symptoms develop within the next 8 hours, he notes.

If a cat comes in with symptoms of amphetamine poisoning, the docs will have to begin a more aggressive treatment, starting with sedatives (to control agitation and possible seizures), a cooling bath, and possibly medication to block one of the three neurotransmitters (serotonin) whose activity is enhanced by Adderall.

Currently, Salem Sreenivasan points out, the poison control center has data on how only 19 of the 152 cases fared. Three cats were treated before they developed any symptoms. Fifteen more symptomatic cats were treated and recovered. One died.

Why report this at SOT? “There’s almost no information about amphetamines in cats out there in the [scientific] literature,” Gwaltney-Brant says. Reporting the data in this venue also highlights the role of the poison control center, she says. “We have 30 years worth of [toxicology] data available,” but no time to write most of it up. Presenting a glimpse of what the center has learned about this drug could advertise what other information might be mined by toxicologists interested in companion-animal poisonings.

Does Adderall’s manufacturer, Shire US Inc., of Wayne, Penn., know about the drug’s risk to cats? “I’m sure the company has no clue,” Gwaltney-Brant said.

To check, I phoned Shire today and spoke with Matt Cabrey, its director of corporate communications. He confirmed that indeed, the company was unaware of Adderall’s palatability to cats. So there are naturally no plans to add any warning to the drug’s label, he says.

Maybe pediatricians should become another target audience for these tox data. They prescribe the drug. And they interact directly with the people who bring it into their homes. Then again, doctors should probably mention something periodically to their patients about just generally safeguarding all drugs from pets.

Right now, Adderall is probably one of the top three human drugs that the poison control center gets calls about for cats, Gwaltney-Brant says. But add in the crisis queries for dogs – about 80 percent of those overall – and the picture changes. For them, she says, “Ibuprofen is the number one call we get, because that’s what dogs get into most.”

It can cause kidney failure and ulcers in the digestive tract. “And unlike Adderall, where cats will develop symptoms within hours, ibuprofen’s damage can take two to three days before it becomes clinically apparent,” she notes. “So if we wait for symptoms, some pretty bad stuff may already have occurred.”

So how much would it take to kill a dog or cat? “For anything under 10 pounds, perhaps as little as a single 200 milligram pill,” she says. Of course, she adds, unlike cats, dogs seldom stop at a single pill. If they get access to a bottle with a 100 or more, she says, dogs will eat them all.

Naproxen, another pain reliever, is even more toxic to dogs and cats, she says. “So just one tablet in a smallish dog could be potentially life threatening.”

Anyone can get help diagnosing a potential poisoning threat from the Animal Poison Control Center at (888) 426-4435. Most consultations – and it provides an average of 140,000 each year – will come with a $65 fee.

Janet Raloff

Janet Raloff is the editor of Science News for Students, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer.

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