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Sept. 10, 2018 -- A surge in dangerous side effects and overdoses has put the spotlight on cannabinoid drugs that go by names like K2, Spice, Mr. Happy, Scooby Snax, and Kronic. Between March and June of this year, these drugs were linked to more than 160 cases of severe bleeding and four deaths in central Illinois. In August, more than 100 people overdosed in a New Haven, CT, park within a 2-day period.

WebMD asked two synthetic drug experts how K2 and Spice affect the body, and what risks they can pose.

What are K2 and Spice?

Cannabinoids are chemical compounds found in marijuana plants. K2 and Spice are names used to describe a group of drugs known as synthetic (lab-made) cannabinoids. They're made from dried plant materials that have been sprayed with mind-altering chemicals.

These synthetic drugs were originally designed by scientists to use in research. Once the production methods were published in scientific journals, enterprising drug manufacturers used the directions to make illicit drugs they could sell.

In 2008, the first reports of these drugs appeared in the United States. Between 2010 and 2011, calls to poison control centers due to synthetic cannabinoid use jumped by 240 percent.

How do people use them?

The most common way people use these drugs is to roll the dried plants into "joints" or put them into pipes and smoke them like traditional marijuana. They're also sold in liquid form and inhaled in e-cigarettes or other devices. Sometimes people add them to herbal tea or food.

Are K2 and Spice the same as marijuana?

Drugs like K2 and Spice are sometimes called "synthetic marijuana" or "fake weed," but experts say these are misleading terms. Marijuana is a plant that's grown for both medical and recreational use. Synthetic cannabinoids are plant material that's been sprayed with an active drug.

The drugs in products like K2 and Spice aren't chemically related to THC, the active ingredient in marijuana. Both types of drugs bind to the same cannabinoid receptors in the brain, but K2 or Spice drugs bind to these receptors much more strongly and produce more intense effects. Synthetic cannabinoids can be up to 100 times more potent than THC.

What's in K2/Spice products?

That's hard to know for sure, because they can contain many different active ingredients. "Hundreds of synthetic cannabinoids have been identified. What's in these products is anyone's guess," says Michael Baumann, PhD, chief of the Designer Drug Research Unit of the National Institute on Drug Abuse Intramural Research Program.

Each product can contain one chemical or a cocktail of different chemicals. He compares taking these drugs to "playing Russian roulette." "You don't know what you're getting when you buy it," he says.

Complicating the issue is the lack of consistency in production. The same drug can be totally different depending on when you buy it.

"Despite the fact that the packages look pretty slick, these drugs are being illicitly manufactured and sold. There's no quality control going on with them," says William Fantegrossi, PhD, associate professor of pharmacology and toxicology in the College of Medicine at the University of Arkansas for Medical Sciences.

Because the active chemical is sprayed over the plant material, "Even within the same package, you can wind up with different amounts of the drug. There's no way to control the dose you're getting," says Fantegrossi, who has extensively studied synthetic cannabinoids.

What effects do these drugs have on people who use them?

These drugs produce effects similar to marijuana, including:

  • Relaxation
  • Euphoria -- intense happiness
  • A heightened awareness of people and things around you

Because synthetic cannabinoids are more potent, the high is more intense than with marijuana.

Are they safe?

No, but many people mistakenly think they are. "Marijuana is becoming legal in more and more states. This is giving the impression that marijuana is safe, and that these drugs are safe," Baumann says. "That's absolutely a false impression."

Synthetic cannabinoids can cause dangerous side effects like:

Between 2011 and 2017, U.S. poison control centers received more than 31,000 calls related to synthetic cannabinoid effects.

K2/Spice products can also be laced with toxic substances. The drugs that caused severe bleeding in Illinois were tainted with brodifacoum, a chemical found in rat poison. People who were affected had symptoms like blood in their urine, severe bloody noses, coughing up blood, and internal bleeding.

People have overdosed on synthetic cannabinoid drugs, but it's hard to know how much of the drug it takes to overdose. "We don't know what a safe dose should be," Fantegrossi says.

Researchers still don't know what long-term effects these drugs might have. Prolonged marijuana use can affect a young person's developing brain and lead to problems with memory, thinking, and learning. "The expectation is that a drug that's more powerful than THC has to have at least the effects of THC," Fantegrossi says.

How many people use them?

Up to 4% of people have used synthetic cannabinoid drugs. Users tend to be male, and in their late teens to early 20s. Many of them also use other drugs.

Are these drugs addictive?

Much of what scientists know about synthetic cannabinoids they've learned from studying THC in marijuana.

Long-term users of these drugs do develop tolerance and dependence, Baumann says. Tolerance means that your body no longer responds to the drug in the same way, and you need to take more and more of it to have the same effects. Dependence means that you need to keep taking the drug to avoid withdrawal symptoms like headaches, anxiety, and irritability.  Learn more: Myths about addiction recovery.

Are they legal?

When these drugs first appeared, they were sold over the counter in places like convenience stores, truck stops, and novelty shops. At the time, the ingredients they contained weren't illegal.

By 2010, several states had passed laws banning the sale of synthetic cannabinoids. In 2012, President Obama signed the Synthetic Drug Abuse Prevention Act, which classified many of the active ingredients in these products as Schedule I drugs -- the same category as heroin and ecstasy.

Yet prosecuting sellers of these drugs has been like hitting a moving target, because they've found clever ways to bypass the laws. "Drug dealers got smart and started to figure out that you could make a very small change to the chemical structure," Fantegrossi says. "When you do that, it's not the same as the drug on the books."

He says that by the time drug enforcement officials figure out what chemical is in a drug and get regulations passed, "the people who are manufacturing it have already stopped making it and started making another drug."

Drug enforcement has tried to keep up. The federal government and many states have passed laws banning broader categories of ingredients, instead of trying to focus on specific chemicals.

K2/Spice products have also added labels that their products are "not for human consumption." Now, some states have made it a crime to try to get around the law with this claim. But it's been hard for law enforcement to go after everyone who sells these products -- especially when many of them are street dealers or online sellers.

As more states legalize marijuana, the distinction between the real thing and synthetic cannabinoids becomes increasingly important. "I hate it when people call these things 'synthetic marijuana' or 'fake marijuana,' " Fantegrossi says. "People say, 'Real marijuana is pretty safe, so the fake stuff can't possibly be bad for you. This does a disservice to what these drugs really are. They will always be much more powerful than the most potent marijuana anyone has ever smoked."

WebMD Health News


American Association of Poison Control Centers: "Synthetic Cannabinoid Data: July 31, 2018."

Michael Baumann, PhD, chief, Designer Drug Research Unit, National Institute on Drug Abuse Intramural Research Program.

Brain Research Bulletin: "International trends in spice use: Prevalence, motivation for use, relationship to other substances, and perception of use and safety for synthetic cannabinoids."

CDC: "About synthetic cannabinoids."

Clinical Pharmacology & Therapeutics: "Cannabinoid abuse and addiction: Clinical and preclinical findings."

Current Psychiatry Reports: "Adverse effects of synthetic cannabinoids: Management of acute toxicity and withdrawal."

Drug and Alcohol Dependence: "Synthetic cannabinoids: Epidemiology, pharmacodynamics, and clinical implications."

Drug Policy Alliance: "Synthetic Cannabinoid Fact Sheet."

William Fantegrossi, PhD, associate professor, pharmacology and toxicology, College of Medicine, University of Arkansas for Medical Sciences.

Illinois Department of Public Health: "Fourth Death Related to Synthetic Cannabinoids," "More Synthetic Cannabinoids Cases."

National Institute on Drug Abuse: "What are Synthetic Cannabinoids?" "What is Marijuana?"

NPR: "Connecticut Health Officials Respond to Synthetic Marijuana Overdoses."

The American Journal of the Medical Sciences: "Synthetic Cannabinoids."

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