The recent distribution of K2, a catch-all street name for synthetic cannabinoids, has caused one of New Haven’s worst health crises in years.

More than 100 victims overdosed on K2 over the course of a week earlier this month. Dealers targeted regular drug users and distributed most of this synthetic cannabinoid in small plastic bags on the morning of Aug. 14 at the New Haven Green. After using the drugs, the victims exhibited various symptoms, such as not being able to breathe on their own. Others arrived at the hospital fully sobered.

This is not the first time the Elm City has seen a string of K2 overdoses. The synthetic drug caused five people to overdose in January and another nine in February. So what exactly is the drug that has caused so many problems in New Haven?

“It is important to understand that there are at least 50, if not much more, chemical variants of synthetic cannabinoids and they differ in chemical formulas,” said Asim Tarabar, a toxicologist who has worked on some K2 overdose cases.

Tarabar said the victims from the Green specifically overdosed on the synthetic cannabinoids fubinaca and pinaca. He added that other, newer synthetic cannabinoids — whose chemical structures and markers have not yet been identified, making detection difficult — may also have been present in the samples.

Although marijuana and synthetic cannabinoids act on the same receptors in the brain to cause feelings of euphoria, these drugs are two distinct substances. Importantly, synthetic cannabinoids can cause physiological complications typically not seen after marijuana use, such as nausea, vomiting, psychosis and even heart attacks, strokes or renal failure.

Marijuana grows as a plant, and its buds naturally contain more than 500 chemicals. The two most notable cannabinoids found in marijuana are delta-9-tetrahydrocannabinol and cannabidiol, abbreviated as THC and CBD, respectively.

THC is the main psychoactive constituent of marijuana, but the chemical does not cause a particularly dramatic response in the brain compared to that generated by synthetic cannabinoids. CBD is thought to play a protective role in marijuana users by counteracting some of THC’s adverse physiological effects, said Deepak D’Souza, a psychiatry professor at the School of Medicine.

But K2, also known as spice, does not contain THC or CBD but rather synthetic cannabinoids, man-made compounds that produce a response in the brain 10 to 200 times stronger than the effect generated by THC. Synthetic cannabinoids are mixed with potentially harmful chemicals and dissolved with alcohol, then sprayed onto a plant-like substance like potpourri or lawn clippings to create smokable K2.

According to Tarabar, it is difficult to predict how patients will respond to synthetic cannabinoids. Some samples sold on the street have been found to contain multiple versions of synthetic cannabinoids, which, depending on the dosage, can interact with one another and cause unique responses in patients.

“I’m not sure that we will be able to tell every time [that] you took this substance, and this is going to be your effect, because it is going to be different for different people,” Tarabar said.

K2 manufacturers have complete control over what goes into their product and because of this, users are blindsided about what they are actually ingesting. In fact, D’Souza has encountered K2 samples that have been laced with dog dewormer and a number of other chemicals including PCP and methadone, a drug that blocks the euphoric feeling caused by opiates. Other batches of synthetic cannabinoids have been cut with fentanyl, an opioid 50 to 100 times more potent than morphine, and anticoagulants found in rat poison, according to Tarabar.

In some overdose cases, it is impossible to know exactly what chemicals were in the ingested drug sample. Instead, emergency physicians focus on treating the patient’s symptoms, Tarabar said.

He added that when overdose patients are admitted into a hospital, the physicians maintain the patient’s airway and control any agitation as their bodies metabolize and eliminate the drug.

“When the drug is gone, most of the time if we are able to preserve their vital organs their brain, their lungs, their kidneys they survive and they do OK,” he said.

The recent surge of K2 overdoses ended with no fatalities. Indeed, some overdose victims returned to the Green for more of the drug immediately after receiving treatment for their initial overdose. To experts, that demonstrates the vice grip addiction can have on drug users.

“[Repetitive drug use] can change the wiring of the brain such that it changes people’s reward pathways and they make choices and decisions they would not have made otherwise,” said Kathryn Hawk, assistant professor of emergency medicine at the School of Medicine.

Hawk added that emergency departments affiliated with the School of Medicine help connect overdose patients to addiction treatment options.

“What we do know is that addiction is treatable and we actually do have a very robust treatment network in New Haven,” Hawk said. “The APT foundation, the SCRC and the addiction recovery clinic are some of those programs –– and they had reached out as this was happening and asked how they could help and put people into treatment.”

The emergency departments affiliated with Yale’s medical school are also becoming more proactive and initiating advanced treatments, such as prescribing drugs like suboxone that manage opioid dependence, said Andrew Ulrich, vice chair of operations for the department of emergency medicine at the Yale School of Medicine.

Nevertheless, Ulrich, who has treated more than a dozen K2 overdose patients, said synthetic cannabinoids pose “a true public safety issue.”

“I think unfortunately this is not the last time we’re are going to see stuff like this — I think we will continually see that the drug use and the drug abuse pattern in New Haven is very significant,” he said.

Marisa Peryer | marisa.peryer@yale.edu

MARISA PERYER