Cannabis treatment for sick dogs lags behind US, but Colorado expert urges caution – ABC News

Paddy is a 15-year-old golden retriever, much loved but slow on his legs.

He is on medication for arthritis and has to have blood tests every six months to check for kidney damage — a common side effect.

„It can also cause vomiting, but he’s OK, as long as he gets fed a lot,” his owner Della Stevens said.

„We give him one tablet at night and he deals with it alright. Without it, he’d really struggle to get up and down.”

It is still an oddity in Australia but in many US states, medicinal cannabis medications including tetrahydrocannabinol (THC) — the psychoactive component in cannabis — are being used as a treatment for pets with conditions such as arthritis and epilepsy. 

It is a big and growing business. 

According to US market research firm Brightfield Group, consumers spent $US426 million ($A551m) last year on pet products containing medicinal cannabis of some kind. 

That number is expected to jump to $US629 million ($A814m) by the end of this year and $US1.1 billion ($A1.4b) by 2025. 

Studies show early positive signs

Stephanie McGrath from Colorado State University is a veterinary neurologist who has conducted clinical trials using medicinal cannabis to treat seizures in dogs.

One study looked at the effect on 16 dogs who were being treated with standard anti-convulsive therapy.

Nine received cannabinoids (CBD) – compounds found in cannabis — and THC while seven were given placebos.

„It was very promising,” Dr McGrath said.

„We showed a significant decrease in seizure activity between the treatment group and the placebo group.”

The study also found that the dogs that absorbed CBD at a greater rate also had the greatest reduction in seizures.

„In the US there’s an FDA-approved medicine for children with epilepsy and it was exciting to show that it may have a very similar effect in dogs as well.”

The CBD treatment also came without the liver disease and pancreatitis that can accompany anti-convulsive therapies.

A previous study looking at the effectiveness of medicinal cannabis on osteoarthritis in dogs was less convincing, but Dr McGrath is lining up another project to look at that nexus again later this year.  

Australia lagging behind

An Australian medicinal cannabis company that sources some of its raw materials from Tasmania, Auscann, recently completed a clinical trial in the US that looked at 46 dogs with osteoarthritis.

The randomised, double-blind, placebo-controlled trial tested the effects of tetrahydrocannabinol (THC) — the psychoactive compound in cannabis — and CBD on the mood, pain and lameness of the dogs over eight weeks.

The company told the Australian Securities Exchange: „A total reduction in veterinary lameness scoring was observed in all dogs treated with CPAT-01, showing improvement over time, which was numerically better for treated dogs compared with placebo.”

Some hemp-based products, which include very low levels of THC and do not affect an animal’s mental state, are available in Australia. 

But the Australian Pesticides and Veterinary Medicines Authority has not approved a single medicinal cannabis product for veterinary use in Australia and, in a statement, said that before any were authorised they would have to meet the statutory criteria, including safety and efficacy.

What happens if a pet overdoses on cannabis?

Not much, as it turns out, unless they eat a lot of other dangerous stuff as well.

Cannabis is legal in Colorado for recreational purposes as well as medical treatment.

Professor of Emergency and Critical Care Medicine Tim Hackett, also from Colorado State University, has treated hundreds of animals brought in with marijuana toxicity after eating their owner’s stash.

He said after Colorado legalised cannabis use, the number of dogs admitted to the ED went from a handful a year to almost one a day.

„This is a dog problem; cats don’t eat this stuff,” Dr Hackett said.  

„A human will know to stop after one gummy bear, but a dog will eat as much as they can, and then they come in with a range of systems from mildly impaired to unconscious and barely able to breathe.

„For the most part, they recover pretty well.

Eating too much oil, which is often used as a carrier for medicinal cannabis, can also cause pancreatitis and death.

More data needed

Although medicines containing marijuana are available for pets over the counter in many US states there is still very little research to prove their therapeutic benefits.

„We still don’t understand things like, how much do you dose the dog to get a similar level as you get in a person?” Dr Hackett said.

„They have very different metabolic rates and they handle things differently. A single paracetamol in a cat can be fatal.

„We’re really in unknown territory because the pharmacokinetics (how the body deals with medication) still haven’t been done.”

As for Ms Stevens, she’s open-minded about cannabis treatments.

„If it didn’t have the side effects, like the damage to the kidneys, I’d give it a go,” she said.