WEDNESDAY, Feb. 24, 2016 (HealthDay News) -- Some tourists who have visited Colorado to sample the state's legal marijuana haven't been able to handle their high, prompting a steep increase in pot-related trips to the emergency room, new research indicates.
The number of out-of-state visitors suffering marijuana-related medical problems who landed in the emergency room of the University of Colorado Hospital doubled between 2013 and 2014.
That's according to a research letter published Feb. 25 in the New England Journal of Medicine.
Retail sales of marijuana first began in 2014, the researchers noted.
During that same 2013-14 period, pot-related ER visits by state residents stayed steady. This suggests that local residents have become better educated when it comes to using marijuana, said study co-author Dr. Andrew Monte, an assistant professor of emergency medicine at the University of Colorado School of Medicine in Aurora.
"People in Colorado are becoming more experienced with use of these products," Monte said. "Sometimes visitors to the state, it's more difficult to get the educational information in their hands. They may be less experienced with the particular products in the state. They haven't been exposed to the deluge of public health messaging."
Colorado was one of the first states to legalize recreational use of marijuana, with voters first approving the measure in November 2012.
For the new report, Monte and his colleagues reviewed billing codes for the emergency department at the University of Colorado Hospital in Aurora. The ER sees about 100,000 patients per year, the study said.
Tourist visits to the ER possibly related to marijuana jumped from 85 per 10,000 in 2013 to 168 per 10,000 in 2014, the researchers found.
At the same time, visits by state residents did not change much -- 106 per 10,000 in 2013, compared with 112 per 10,000 in 2014, the research showed.
These numbers mirror statistics gathered by the Colorado Hospital Association, which saw pot-related ER visits by tourists rise statewide from 78 per 10,000 visits in 2012 to 163 per 10,000 visits in 2014, the researchers noted.
Tourists most often land in the ER because pot has exacerbated existing medical conditions, Monte said.
Primarily these are psychiatric problems like schizophrenia, anxiety or depression, but people also have come in because pot smoke has triggered their asthma or sped up their heart rate, he said.
Overindulging in edible pot also can also cause severe vomiting. "We see a fair number of those," Monte said.
And finally, there are some people who are simply too intoxicated and just don't feel well, he said.
Medical marijuana has been legal in Colorado since 2000. In fact, most state residents still buy their pot on a medical basis to avoid the high recreational taxes, said Dr. Doug Hill, a Colorado-based emergency medicine specialist and spokesman for the American College of Emergency Physicians.
The decade of legal medical marijuana has given state residents the savvy to know how to use pot safely, Hill and Monte said.
Tourists are more apt to make mistakes such as consuming too much edible marijuana because they don't feel the effects immediately.
For example, pot-laced candy bars are supposed to be broken into ten pieces, with each piece containing a full 10-milligram serving of THC, the chemical in pot that gets you high, Hill said.
But pot that's eaten instead of smoked can take up to an hour to kick in, and even then the high tends to be more mellow, Hill said. Tourists eat one piece, become impatient when they don't feel anything immediately, and then down more of the product, he said.
"They eat the whole candy bar, and then they get blasted by the effect," Hill said.
Paul Armentano, deputy director of NORML, which promotes marijuana legalization, said state laws forbidding the use of marijuana in public places also may play a role in the problem, prompting tourists to choose pot edibles that are trickier to use.
"It is likely that these experiences can be mitigated or avoided by better product labeling, limiting such products to single-serving sizes, and by the establishment of licensed, zoned facilities that permit the adult use of cannabis on premises during specific hours," Armentano said.
Armentano agreed that consumer education is key.
"The imposition of sensible regulations on the cannabis industry, coupled with better public safety information and greater consumer responsibility and accountability, are the best strategies to address cannabis-specific health concerns due to the inadvertent ingestion or over-ingestion of edible products," he said.
The problem with out-of-state visitors misusing recreational pot is so well-known, Hill said, that tourism boards have taken out billboards that say, "Don't let a candy bar ruin your vacation. With edibles, start low and go slow."
The Colorado Legislature also has pumped more money into public education, and is putting pressure on dispensaries to better walk tourists through how to safely use marijuana products, Hill and Monte said.
States toying with legalization "should learn from Colorado's mistakes, in that some of these types of point-of-sale education should be put in preemptively," Monte said.
Visit the Colorado's website for more on safe marijuana use.