Toxic to dogs · Medications

Is Methylphenidate toxic to dogs?

High severity No safe amount — No amount is considered safe.

Yes, Methylphenidate is highly toxic to dogs. Exposure can cause serious illness and needs prompt veterinary attention. No amount is considered safe.

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Is methylphenidate toxic to dogs and cats?

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What to do right now

  1. Call your vet or an animal poison line now, even if your dog seems fine. Signs can start within minutes. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435.
  2. Don't make your dog vomit at home unless a vet or poison-line expert tells you to. Vets don't make a dog vomit once it is agitated or trembling, and often not after standard tablets, because signs start so quickly.
  3. Keep the bottle or package. Note the product name and strength, whether it is extended-release (long-acting), how many pills or patches may be missing, when it happened and your dog's weight.
  4. Keep your dog in a quiet, dim room and handle it as little as possible while you get help. Poisoned dogs can become aggressive.
  5. If your dog swallowed a patch, tell the vet: signs can last until the patch has completely left the body.

Go to an emergency vet if

  • Your dog swallowed any methylphenidate and you can't reach your vet or a poison line. Go to the nearest emergency clinic.
  • Your dog is restless, pacing, circling, can't settle, or is agitated or aggressive.
  • Your dog trembles, walks unsteadily or has a seizure.
  • Your dog pants hard, feels very hot or has a racing heart.
  • Your dog has dilated pupils, drools, vomits or has diarrhea.

Symptoms to watch for

  • agitation
  • dilated pupils
  • tremors
  • seizures
  • elevated heart rate
  • high blood pressure
  • drooling
  • vomiting
  • diarrhea
  • panting

How much is dangerous

Small amounts can make a dog ill, and the dose doesn't reliably predict how sick a dog gets. In an ASPCA Animal Poison Control Center study of 128 dogs, the lowest dose that caused signs was 0.39 mg per kg of body weight, and 11 of 14 dogs that swallowed less than 1 mg/kg had signs. The Merck Veterinary Manual reports a high body temperature and a fast heart rate from 0.3 mg/kg, and a Pet Poison Helpline toxicologist gives 0.5 mg/kg as the toxic dose for dogs and cats. Deaths are uncommon: 3 of the 128 dogs in the ASPCA study died, all after eating extended-release pills, at doses of 10.2, 15.4 and 31.1 mg/kg. A death has also been reported in one dog at 3.1 mg/kg, though the details of that case weren't reported. Your vet works out the dose from the tablet strength, how many tablets are missing and your dog's weight.

When signs appear

Signs can start fast. The ASPCA says they can appear within 15 minutes or be delayed by several hours, depending on the product. A Pet Poison Helpline toxicologist says signs from standard (immediate-release) tablets can start within 20 to 30 minutes and last 12 to 24 hours, while extended-release forms and patches may delay signs by 4 to 6 hours and cause effects for a day or two. In the ASPCA study, most signs in dogs that ate standard tablets developed within 3 hours, and dogs that ate extended-release pills showed their first signs anywhere from within minutes to slightly more than 24 hours later. A dog that chews an extended-release pill may absorb more of the drug at once. The ASPCA says that once signs start, they can last 24 to 72 hours. Don't wait for signs before you call your vet.

Why it's dangerous

Methylphenidate acts as a central nervous system stimulant, leading to over-stimulation of the nervous and cardiovascular systems.

Toxic compound: Methylphenidate

How vets treat it

There is no antidote. If your dog has no signs yet and swallowed extended-release pills, the vet may make it vomit, then give activated charcoal. Vomiting is generally not recommended after standard tablets, because signs start so quickly, and it is unlikely to help more than 1 hour after standard tablets or 2 hours after extended-release pills. A sedative such as acepromazine calms agitation, tremors and pacing. Diazepam isn't a first choice, because it can make the excitement worse. Seizures are treated with medicines such as levetiracetam (Keppra) or phenobarbital, and cyproheptadine is given for signs of serotonin syndrome, such as vocalizing and stiff muscles. Your dog gets a drip (IV fluids), and the vet monitors its heart rate and rhythm, blood pressure and temperature, and cools it with fans or cooling vests if it overheats. A swallowed patch may be removed with an endoscope. Monitoring lasts at least 12 hours after standard tablets and at least 24 hours after extended-release pills, or until signs have resolved, and the ASPCA advises keeping the pet in the clinic for at least 6 to 8 hours after signs have gone.

Outlook

The ASPCA says ADHD medicine poisoning in pets is treatable. In the ASPCA study, outcomes were known for 34 dogs: 16 never developed signs, 15 had signs and recovered fully, and 3 died or were put to sleep, all after extended-release pills. Organ damage is rare but has been seen, especially in pets whose treatment was delayed and that had significant signs. Dogs with signs usually need to stay in hospital until they have recovered and the drug has left their body.

Where pets are exposed

  • Methylphenidate is a stimulant medicine prescribed to people for ADHD (attention deficit hyperactivity disorder) and narcolepsy. Brand names include Ritalin, Concerta, Methylin, Metadate, Quillivant XR and QuilliChew ER.
  • It comes as standard tablets, chewable tablets, tablets that melt in the mouth, liquids, and long-acting (extended-release) tablets and capsules. Long-acting pills usually hold more of the drug, because they are designed to work for 8 to 12 hours in people.
  • Skin patches. Methylphenidate also comes as a patch. Dogs do swallow patches, including used ones found in the trash, and most of the drug is still active after a patch is thrown away.
  • A dropped pill or a pill bottle. Pets can swallow a dropped pill or chew up a whole container.
  • Children's medicine. Children in many households take ADHD drugs, and flavored chewables and liquids can appeal to pets. The flavoring may contain xylitol.
  • Other ADHD stimulants, such as Adderall, Focalin and Vyvanse, belong to the same family of drugs and cause similar signs in dogs and cats.

Prevention

  • Never give your pet methylphenidate or any other ADHD medicine unless your vet prescribes it. The Merck Veterinary Manual says these drugs currently have no therapeutic use in pets.
  • Store ADHD medicines, including children's chewables and liquids, in a closed place out of pets' reach, and keep count of the pills.
  • Pick up a dropped pill straight away, before a pet can swallow it.
  • Get rid of used patches and unneeded pills where pets can't reach them. MedlinePlus recommends a medicine take-back program.
  • Keep people's and pets' medicines apart. In one published case, a cat was poisoned by a methylphenidate tablet it was given by mistake.
  • Take extra care when school starts. The ASPCA usually sees a spike in calls about pets and ADHD medicines when students go back to school.

Good to know

Methylphenidate is very similar to amphetamines; poisoning can result in severe clinical signs across multiple body systems.

Common questions

My dog ate a Ritalin or Concerta pill. What should I do?

Call your vet or a pet poison line now, even if your dog seems fine. Signs can start within minutes, or hours later with an extended-release pill. Don't make your dog vomit unless a vet tells you to, and keep the package so the vet can check the strength and whether the pill was extended-release. In an ASPCA study, most dogs with a known outcome did well.

How much methylphenidate is toxic to a dog?

Very little. In an ASPCA study of 128 dogs, signs appeared at doses as low as 0.39 mg per kg of body weight, and a Pet Poison Helpline toxicologist gives 0.5 mg/kg as the toxic dose. How sick a dog gets isn't closely linked to how much it ate, so the study's authors recommend monitoring and supportive care whatever the dose. Call your vet with the tablet strength and your dog's weight.

How long do methylphenidate symptoms last in dogs?

It depends on the product. A Pet Poison Helpline toxicologist says signs from standard tablets may last 12 to 24 hours, and extended-release forms and patches can cause effects for a day or two. The ASPCA says signs from ADHD medicines can last 24 to 72 hours once they start. Vets are advised to monitor a dog for at least 12 hours after standard tablets and at least 24 hours after extended-release pills, or until signs resolve.

Is methylphenidate dangerous for cats?

Yes. A single 5 mg tablet given to a cat by mistake caused tremors, agitation, a racing heart and high blood pressure. Cats may not look hyperactive: the ASPCA says a poisoned cat may sit unusually still and stare while its heart rate and temperature rise. Treat any amount your cat swallows as an emergency and call your vet straight away.

Can I give my dog Ritalin to calm it down?

No. Never give your dog methylphenidate on your own. The Merck Veterinary Manual says ADHD drugs currently have no therapeutic use in pets, though methylphenidate was once used to treat narcolepsy in dogs. In dogs, even small amounts can cause severe signs such as hyperactivity, a racing heart and a high temperature. If your dog's behavior worries you, ask your vet.

My dog chewed a methylphenidate patch. Is that dangerous?

Yes, even if the patch was used. Most of the drug is still active after a patch is thrown away, and a dog that swallows one can have significant signs until the patch has completely passed. Signs may be delayed by 4 to 6 hours. Call your vet now: the vet may remove the patch with an endoscope, and dogs that swallow patches usually need a longer stay in hospital.

Sources

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

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