Here’s What Happens When You Mix Cocaine and Ketamine

If you’re a budding club rat, a freak for festivals, or generally in the orbit of people who use “party” as a verb, you might have heard of CK, also known as Calvin Klein: mixing cocaine and ketamine, either by combining the drugs into a single powder or by consuming the two in succession. 

So what do you get when you cross ketamine, the drug that turns the world into one big trampoline park, with cocaine, the drug that makes a guy show you his walk-in closet at 4:30 a.m.? According to users, it’s a dreamy, euphoric boost of energy that combines qualities of both drugs for a more intense high.

Sounds like a woozy good time, right? But, like all drug cocktails, CK can have risks and side effects that range from bad vibes to straight-up fatal, which is why it’s critical for people to educate themselves about harm reduction before they indulge.

“Cocaine and ketamine, when taken together, create a synergistic effect,” meaning the two drugs work in tandem to enhance each others’ effects, said James Giordano, a Georgetown University neurology and biology professor. 

“Individuals who do CK will say they get a profound rush where they feel very, very good, very pleasurable,” Giordano told VICE. He said the combination has the swift onset of a cocaine high, “and with the ketamine on board, it lasts longer.”

Joseph Palamar, an associate professor of population health at New York University, said that some people combine cocaine and ketamine on a bump-by-bump basis for practical (in the party sense) purposes: Cocaine cuts through ketamine’s dissociative fog and leaves users a little sharper than they would be on horse drugs alone, while ketamine softens the teeth-clenching, motor-mouthing effects of coke. “It’s the same reason why a lot of people use cocaine when they’re drinking alcohol,” Palamar said. “If you want to drink more, or you're a little too drunk, you take a quick walk to the bathroom and do a bump or a line of coke. It's about functionality.” 

So, how do you toe the line between a good time and unsafe behavior? Here’s what you need to know when you’re deciding whether or not you want to play “pass the keys.”

Cocaine and ketamine each have a reputation for generating euphoria —and combining them cranks their impacts on the brain up to an 11.  Cocaine is a stimulant that acts on the central and peripheral nervous systems to elevate mood, along with heart rate and blood pressure. Ketamine is a dissociative hallucinogen that acts primarily on the brain’s receptors for a neurotransmitter called glutamate. K has been found to help rebuild synaptic connections in people with depression, which is the reason why it’s such a hot experimental treatment right now. 

“Cocaine, it’s the dopamine gas pedal. Ketamine takes the brakes off the dopamine system,” Giordano said. In layman’s terms, that means it makes you feel really fucking good, thanks to a flood of dopamine, the neurotransmitter commonly linked to pleasure and excitement. On its own, cocaine ups the brain’s dopamine levels, like flooring it ups a car’s speed, while ketamine alone lessens the brain’s ability to control dopamine release, like cutting the brakes would take away a driver’s ability to slow down. “Working together, that really increases the dopaminergic activity of the brain,” Giordano said.

“Using even a low dose of cocaine together with [another drug], like ketamine, is going to increase the effects of both drugs together, which might be very different from those two drugs alone,” Giordano said. “It’s not just a question of ‘A plus B,’ but really more ‘A times B,’ where the effect is going to be greater than the simple sum of their co-administration.”

From a user’s perspective, CK is a sharper, more functional version of the out-of-body, out-of-mind ketamine trance—it’s easier to follow the thread of a conversation or weave through a pulsing dance floor to grab a flimsy plastic cup of water than it would be on ketamine alone. The high is a softer, dreamier version of the metallic cocaine buzz, as ketamine rounds out the cokey enhancement of uncomfortable physical and mental sensations, like waiting for a cab or listening to someone who isn’t you talk when you want to be talking. Take enough CK and you might see twinned images when you try to focus on a TV screen, which would normally be kind of alarming—but, on CK, it’s just another piece of giggly fun to babble about with your friends.

According to Giordano, “The profound dopaminergic effects from combining cocaine and ketamine, both in the brain and in the rest of the body… that’s a bomb waiting to go off.” And not in a fun way.

“​The increased level of dopamine in the brain can lead to a whole host of neurological problems,” he said. “Seizure, in some cases coma, high level of disorientation, profound hallucinations, and a whole range of other drug induced psychotic symptoms. And the peripheral effects of ketamine, together with cocaine, really amplify the possibility for spikes in blood pressure, variations in heart rate and contraction, and increased liability for stroke.” 

There are also major risks in terms of whether the drugs you’re using are pure, especially because you’re doubling your bet on a given substance’s safety by taking two different powders. “I would be a little hesitant in 2022 about taking a powder from anyone, because it can contain other things,” Palamar, who specializes in researching club drugs, said. “Any powder that’s going around, even ketamine, can have fentanyl if you don't know where it really came from.” 

While data on how widespread/frequent instances of fentanyl contamination in other recreational drugs is piecemeal and often collected on a state by state basis,  Rachel Clark, an education manager at the drug testing/harm reduction nonprofit DanceSafe, said the danger is real, especially when it comes to cocaine. “It’s not a myth that there is fentanyl in cocaine right now,” she said. “There's a lot of dumb shit going around—urban legends about where fentanyl is currently being found—but there are health departments that confirm this across the country.” 

Palamar also pointed out that the profound dissociative effect of ketamine, even tempered with cocaine, can also be an issue for users—especially in unfamiliar environments. “Behaviorally, ketamine is 100 times more dangerous than cocaine,” Palamar said. “You’re disconnected [from reality]. You could be raped, you could be assaulted, you could be mugged. If you're walking outside, you could get hit by a car.” 

As a dissociative, ketamine can also make it more difficult to discern important things like what you’re taking, how much you’re taking, and how often you’re taking it—which Clark said can be exacerbated by the “let’s do more!!!!!!” tendency that cocaine is famous for inducing. “Both of these substances inherently as short acting substances that tend to produce a euphoric and short-acting rush—especially cocaine—are very prone to compulsive redosing,” Clark said. “If you're a person who is prone to compulsive redosing, I would exercise extreme caution with this combination.”

Buy both drugs from a known dealer, preferably someone who you or someone you trust has purchased drugs from before. Then, test your stash! This will reduce the possibility of an accidental overdose on something like fentanyl, and reassure you that what you’re taking is most likely what you think you’re taking. (It’s worth noting here that tests aren’t guaranteed to be perfectly accurate every time, or that people will use them correctly every time.) Order fentanyl test strips and more extensive drug testing kits from a trusted entity, like DanceSafe—not Amazon—or ask local harm reduction organizations in your area if they can hook you up.

It’s important to research potential interactions between coke, ketamine, and any drugs you take on a daily or regular basis to avoid a bad reaction. “It’s not enough to just be like, I’m doing a stimulant, does that stimulant interact with an antidepressant?” Clark said. “It’s not about that. It’s about the specific, individual drugs that you are combining, including things like allergy medications, and anything over the counter. It’s a lot more complicated than people realize.” She recommended PsychonautWiki (it’s the new Erowid!) as a hub for people who want to research drug interactions and read about other peoples’ experiences taking and combining substances. 

First and foremost: Palamar recommended keeping your cocaine and ketamine separate, versus mixing them in a single container, so you can keep a closer eye on how much of each you’re consuming. 

Once you start taking ketamine and cocaine together, low and slow is the name of the game, with your doses spaced out as much as possible. If you think you don’t feel anything, wait 10 to 20 minutes before you dose again. While cocaine tends to take effect rapidly, within 5 to 10 minutes, ketamine can take more time to kick in—up to 25 minutes depending on one’s personal body chemistry. Like all drugs, keep in mind that you can always take more and you can never take less. 

To avoid that compulsion to dose again and again and again, only carry the amount that is safe for your individual use so you’re less likely to overdo it, and set a time limit for yourself on how long you’re going to use these drugs in combination—think a two- to three-hour window within the entirety of your night (or day, whatever!) out. 

Even if you’ve banked plenty of experience using cocaine and ketamine separately, Giordano recommended taking a beginner’s dose the first time you try CK. “When you add the second drug, that second drug is working atop the first,” he said.  “So, when you then begin to mix in ketamine, go with a lower dose of cocaine—the lowest dose of cocaine that you feel is viable for you. Begin with that effect, and be very aware that the effects produced by both drugs together are going to be perhaps very, very different than would be anticipated for either of those drugs alone.”

According to Clark, an average beginner’s dose means 30 milligrams to 60 milligrams of coke or ketamine, though that will always vary person to person. Since those doses are basically impossible to eyeball and are too small to register on most scales, she recommended carrying around some 10 milligram “micro scoops” like the ones DanceSafe sells to ensure accuracy. 

Which drug you use first and the ratio you balance them on is a matter of personal preference, but Clark said she enjoys starting with ketamine and adding cocaine into the mix later in the session. And if you try CK and find the combination really doesn’t agree with you, don’t worry—due to the fast-acting nature of both drugs, you’ll be back to normal relatively soon. “I've seen people who were so fucked up that they were vomiting profusely and rolling around in the dirt and yelling, and within like 45 minutes, they were completely and totally sober at baseline,” she said. “That changes the risk profile as opposed to mixing either drug with something like acid, which lasts about 10 to 12 hours. Either way, the acute effects of mixing coke or ketamine with anything will usually only last about as long as the coke or ketamine do, sometimes a bit longer than usual in the case of ketamine.”

Finally, make sure you’re giving CK a whirl for the first time with people you trust to take care of you if anything unexpected happens. They’re called recreational drugs for a reason—you’re supposed to be having fun! If you play it safe, keep it minimal, and take care of yourself and others, you’ve got the… key to a way better time on CK.

Katie Way is a senior staff writer at VICE. Follow her on Twitter.