California DVM wants clinical trial on medical use of marijuana in pets

Chatsworth, Calif. — A California relief veterinarian is polling pet owners about the use of medical marijuana in animals with the goal of using the survey's results to leverage a clinical study about the drug's efficacy in relieving pet pain.

Dr. Douglas Kramer, who runs an alternative veterinary medicine website called VetGuru.com, was prompted to blog about medical marijuana use in pets after learning about the possible development of a "pot patch" for pain control in dogs, cats and horses by a Seattle company.

Medical Marijuana Delivery Systems (MMDS) of Seattle announced in early 2011 that it would market its patch, Tetracan, for transcutaneous delivery of medical marijuana to humans and animals.

But Kramer says he has concerns about the safety of a transdermal medical marijuana patch developed without veterinary involvement because there is no way of telling how effective it is, and accidental ingestion of the patch could be dangerous to pets.

"From a veterinary standpoint, the recently reported 'pot patch' is an obvious safety hazard and the perfect example of what happens when professionals fail to address a clear, unmet need in their field," Kramer says.

To apply the device, fur would have be shaved and the patch affixed to the skin with an adhesive. Ingestion of the patch by that pet, another pet in the household or a child could result in adverse events, he says, using pain-relief patches already prescribed by veterinarians as an example.

"I've heard of at least two toddlers and several pets that have indeed managed to remove and ingest (fentanyl) patches, receiving the entire three-day time-released dose all at once. Although therapeutic at very tiny micro-doses, fentanyl is considered a toxic substance."

But, even in high doses, current research does not support fatal outcomes in medical marijuana use, Kramer suggests. He says he has never treated a case of marijuana toxicity in a situation where the owner has administered the drug therapeutically. Usually, toxicity cases involve the animal getting into an owner's "stash" and consuming it, resulting in vomiting, diarrhea, ataxia, loss of coordination and tremors, Kramer says, adding he has never seen a fatal case.

And pet owners are interested in more alternatives for pain relief and some already are medicating pets with marijuana on their own, he says.

"As a practicing veterinarian in the state of California, I have personally encountered dozens of clients who are already experimenting with the effects of medical marijuana on their pets. Many have reported that the medical marijuana did indeed result in medicinal benefits similar to those seen in human patients."

Although he does not recommend or prescribe marijuana for medicinal purposes in pets, Kramer says he has interviewed at least two-dozen owners who say they have used medical marijuana to treat their pet's pain—usually because they are suffering from cancer. They report positive results like reduced anxiety and increased appetite," Kramer says.

Historically, prior to its prohibition, Kramer says cannabis was used in a variety of veterinary medications, including colic remedies for horses.

Kramer says while he doesn't promote or recommend medical marijuana use, clients who are using it therapeutically on their pets are coming to him more and more, asking for his guidance on dosage, administration and monitoring of their home "treatments."

"People are using it, and if we as vets don't step in and fill that need, they're going to fill the void because we're not addressing the issue," Kramer says. "My ultimate goal is to have a pain medication somewhere between aspirin or non-steroidal anti-inflammatory drugs (NSAID) without knocking your dog out."

Lisa Moses, VMD, Dipl. ACVIM, serves on the board of directors for the International Veterinary Academy of Pain Management (IVAPM) and told DVM Newsmagazine earlier this year that medical marijuana use could be beneficial to pets if it was delivered in a well-developed product.

"The problem with a lot of stuff is that we know there's a lot of things that should work, but because of manufacturing sloppiness or poor regulation on a supplement, we don't know if our patients are getting what we think they're getting," she said. "There are definitely reasons to believe the active ingredient in marijuana affects certain pain mechanisms in the nervous system. It's something I would definitely be interested in trying if it was available to me."

Practitioners may worry about diversion, but Kramer says he is much more concerned about the diversion of other, more potent veterinary drugs.

"I don't believe that diversion will be a significant issue with medicinal marijuana for pets. In states like California, for example, it is extremely easy for an individual to obtain a medicinal marijuana 'patient card' for themselves from their own doctor. It would be far more expensive and time-consuming for that same individual to go through the trouble of attempting to obtain the marijuana through the manipulation of their veterinarian," he says. "I'm sure there would be some diversion but that's unavoidable and it would pale in comparison to the diversion of some of the other commonly prescribed veterinary drugs."

But clinical trials are a must, he says. Trials have never been conducted directly on animals, but only indirectly for human trials. Testing on dogs for human clinical trials revealed that dogs have the same cannabinoid receptors as humans, Kramer says. But direct research on how the drug affects animals is the next step, he adds.

"The only way I'd feel comfortable recommending it is with clear data. I'm tired of euthanizing animals and watching them suffer and feeling helpless," Kramer says.

So far, he has collected about 50 surveys from owners who are using medical marijuana on their pets, but wants to get 250 to 500 in all before moving forward.

"I want to get the information, know if it works, know if it helps," he adds.