By Ranny Green
Some come in glassy-eyed, stumbling and with dilated pupils. Others have been vomiting, have an accelerated heart rate, are hyperactive, been urinating inappropriately or are nearly comatose.
Those are the scenarios state veterinarians are seeing more often since Washington voters passed Initiative 502 in November 2012 that defined and legalized small amount of marijuana-related products for adults 21 and over.
Marijuana toxicity can occur post inhalation but most cases stem from suspected or known ingestion of cookies, brownies, caramels, gummies or toast coated with marijuana butter.
“Dogs have no stop button when it comes to consuming these things,” says Dr. Donna Mensching, veterinary medical director of VET PETS (Veterinary Poison Emergency Treatment Services) in Seattle, a branch of the Washington Poison Center.
“Marijuana has a wide margin of safety,” adds the veterinary toxicologist, “with death being rare but most patients need medical treatment to recover from poisoning.”
Adding to the complexity of the cannabis craze for veterinarians is the honesty of the owner. Is he or she willing to admit that there is marijuana in the home and that the patient ate something laced with it?
To break through that psychological veneer, Mensching will occasionally ask gently and directly if there is a third party in the home who might be smoking marijuana or has brought in a substance that the dog could have woofed down. “At that point, the owner will usually say ‘yes,’ “she says.
Commercially available urine drug screening tests marked for people are unreliable in detecting marijuana in canine urine, says Mensching, often producing false negative readings.
Dr. Shep Thorp, of The Animal Emergency Clinic in Tacoma, says, “The incidence of marijuana toxicity has increased over the last seven years. Since the legalization of marijuana, we may see a case every other day, or even daily.”
Most patients are decontaminated, he says, with the induction of emesis (vomiting), administration of oral-activated charcoal or intravenous fluids for diuresis (increased discharge of urine). Monitoring parameters, explains Mensching, include heart rate, rhythm, blood pressure, temperature, oxygenation and central nervous system status. Supportive care is often advised for`12-24 hours. The prognosis for complete recovery, adds Thorp, is favorable to good.
Dr. Patricia Talcott, a Washington State University College of Veterinary Medicine veterinary toxicologist, says signs of marijuana toxicity typically begin 30 minutes to an hour following ingestion. Owner recognition and response are key here, either rushing the pet to a veterinarian or contacting the VET PETS Poison Hotline. “Like any other emergency, the quicker the treatment, usually the better the outcome.”
The marijuana discussion in the veterinary corridor isn’t limited to toxicity, however. The use of marijuana-based products for treatment of sick pets is a hot-button topic for many practitioners.
Dr. Lisa Parshley, an Olympia veterinary oncologist, says in a cover article in the May-June issue of the Washington State Veterinary Medical Association’s Washington Veterinarian magazine: “We need to understand that there is a plethora of marijuana information and misinformation available to anyone with a web connection, a radio and television.
“We as veterinarians need to arm ourselves with reasonable, informed and thoughtful answers to questions like: ‘Can I use marijuana to help my cat eat?’ or ‘Will marijuana work against my dog’s pain?’ “
She notes that as of 2012 more than 20 of cannabis-derived phytocannabinoids were the focus of biomedical research and therapy development. The studies include evaluation of these compounds – native and synthetic – as anti-inflammatory agents, appetite stimulants, muscle-spasm therapy in multiple sclerosis and possibly as an anticancer therapy.
Phytocannabinoids are plant (cannabis’s) equivalent to a natural molecule found in animals. These molecules are found in most animals and are used by the nervous and immune systems. “We think the phytocannabinoids are impacting humans and animals by mimicking these molecules,” adds Parshley. “The system targeted by the phytocannabinoid will determine the effect on the body, both good and bad.”
From the studies, three approved therapies (for humans) were developed, she explains, for use in intractable nausea and vomiting and chronic pain.
But she cautions, “As encouraging as these new physiologic and therapeutic discoveries appear we still have many obstacles to overcome prior to prescribing safe, effective and predictable cannabis-derived therapies.”
Without this information all the possible effective yet safe therapies remain a dream, she emphasizes. “Until we are able to fill in the holes of our knowledge we will be limited to the regulatory approved products and use of whole plant or partial plant therapies.”
Safe dosing standards are the biggest unknown here. The potential for unpredictable side effects, serious illness or even patient death looms ahead for any veterinarian prescribing pot pills. Plus, it’s illegal. Should one attempt to do so and it backfires, there is always the threat of litigation and loss of license.
“We have to keep in mind that pets aren’t people,” says Talcott. “How they metabolize medications is different from us. A veterinarian would really be playing with fire should he or she treat an animal with a marijuana medication.”
Marijuana has been classified as a Schedule I controlled substance since 1970. Schedule I is the most restrictive of the federal Controlled Substances Act categories and is reserved for drugs with no currently accepted medical uses and a high potential for abuse. 
The regulatory threshold for clinical research on Schedule I drugs is so high that it poses a major deterrent for health-care and veterinary-care organizations, although some are urging the federal government to reschedule marijuana and allow more research on the viability for new cannabinoid-based medications.
There is an incredible opportunity at this point for the Washington State Veterinary Medical Association and local veterinary associations to reach out to the public with educational seminars, explaining the dangers of marijuana toxicity and pets within the household and detailing regulations surrounding Schedule I substances in veterinary care.
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For now, if you own a pet, keep this contact information near your phone at all times:
Veterinary Poison Emergency Treatment Services
(800-572-5842 or www.vetpets.org.).
Visit the web site to get a glimpse of the wide range of offerings it provides and familiarize yourself about how to deal with pet poisoning.
