A marijuana plant flourishes under grow lights at a warehouse in Denver on Tuesday, Oct. 26, 2010. (Ed Andrieski, AP)
In the 1998 cult-classic movie "Half Baked," characters played by comic Dave Chappelle and his friends get a Rottweiler so high on pot that the dog flies out the window after getting the munchies.

In real life, it's not so funny.

Marijuana is toxic to dogs, and Colorado veterinarians say the number of pets, usually canines, being treated after consuming pot is on the rise.

They're not sure whether pets are getting into marijuana more frequently, or if pet owners are just less fearful about seeking treatment now that adults in Colorado may legally possess small amounts of pot and thousands carry medical-marijuana cards.

Mesa Veterinary Clinic in Pueblo estimated that, so far this year, marijuana-related cases are up about 30 percent from past years. Animal Emergency Care Centers in Colorado Springs said it is seeing an increase in pot-related incidents, with 10 to 20 a month.

A study conducted by Wheat Ridge Animal Hospital and the Colorado State University Veterinary Teaching Hospital found that marijuana toxicity cases quadrupled between 2005 and 2010. Researchers say the increase correlated with the increase in number of registered medical-marijuana users during the same period.

"We're at the point where we ask owners very specifically and multiple times if we think the dog has gotten into marijuana," said Natalie Adams, a vet at the Community Pet Hospital of Thornton.
Community Pet treats four to six animals a month for marijuana toxicity, up from one case every couple of months, she said.

Adams said cases in which an owner has given a pet weed to get them high just for fun are rare.
Instead, pets are victims of poor storage of pot. 

"Put it away, out of reach," Adams said. "Once they got into it once, they will be repeat offenders."
Dogs become agitated after they consume the drug. It affects their coordination and mood, said Jennifer Bolser, a vet with The Humane Society of Boulder Valley. It also may cause incontinence and a slower heart rate. If the pet consumes a large amount of pot, the psychoactive chemical, THC, can cause a dog to suffer seizures, go into a coma or die.

"As long as the dog is treated and decontamination occurs, with mild exposures the dog will not have any long-term effects," Bolser said.

Treatment can range from hundreds of dollars to thousands, if the pet requires hospitalization.
None of the veterinarians who treated pets sick with pot toxicity called police. Even if they had, there are no laws governing animal exposure to marijuana.

"This is sort of uncharted territory," said Meghan Hughes, spokeswoman for the Denver Environmental Health Department. "We just recommend that vets or members of the public contact Animal Control if an animal is in harm's way."

Animal doctors at Mesa Veterinary Clinic have had patients ask for medical-marijuana cards for their pets.
"We see dogs 14 to 15 years old pretty crippled up. If people think it helps their own pain, they think it's an option for their pet," said Mesa Clinic vet Tiffany Barr.

But Barr said there is no research suggesting dogs benefit from marijuana use.
Adrian Garcia: 303-954-1729, agarcia@denverpost.com, twitter/ adriandgarcia