Why Ketamine Makes You Dizzy—And When to Worry

When Amir, a 26-year-old who works in tech, went to an after-hours warehouse in Brooklyn earlier this year, he bought ketamine from his regular dealer. After just one bump, he started to feel uncharacteristically dizzy. The room wasn’t just spinning, as it sometimes did when he was on K—it was doing summersaults, he tells VICE. Amir doesn’t remember much after that except that he started puking on the floor, had trouble breathing, and began to doze off.

Amir says he believes that what his dealer gave him wasn’t just ketamine. But he also says he ignored the initial signs of a potential overdose because he usually felt nauseous on K, anyway. So… what’s a normal amount of dizziness on ketamine, and why does it happen?

Ketamine is an NMDA receptor antagonist that disrupts the normal flow of information in the brain, leading to sensations of dissociation, pain relief, and even hallucinations. Created in a lab in Detroit in the 1950s, it’s been used in the subsequent decades as an anesthetic by veterinarians—which is why you might have heard of K being referred to as “horse tranquilizer,” even though it’s more commonly for on cats and dogs. As an anesthetic, ketamine is also used intravenously on human adults and children.

The sensation of being anesthetized by ketamine is not dissimilar to the feeling of falling into a hole—which is why you might have heard people describe a bad ketamine trip as a k-hole. But ketamine can also bring on feelings of euphoria: This might be because it activates other neurotransmitters in the brain like norepinephrine, which helps with focus and energy. This is why, even though it’s used as a tranquilizer, ketamine can keep you up for hours, although its most potent effects tend to last between 30 minutes to an hour.

In recent years, ketamine therapy has been marketed as an alternative to traditional antidepressants for treating severe anxiety and depression, although we don’t entirely know why it’s so effective. The NMDA receptors that ketamine blocks in the brain are a type of glutamate receptor, responsible for moderating synaptic transmission in the central nervous system. Through a complicated mechanism we’re still learning about, ketamine decreases the release of glutamate in some areas and increases it in others, which can help create new connections in the brain. Because abnormal levels of glutamate have been associated with depression, ketamine’s ability to alter glutamate levels might also be a reason it can treat severe depression more effectively than SSRIs, which solely focus on serotonin. 

So why does ketamine make you dizzy and nauseous? According to Tom Britton, the CEO of the American Addictions Center, ketamine alters the gamma system, which stretches across the entire body. Ketamine also interacts with the gut, which is linked to the balance mechanism in our brains, according to Sam Zand, a psychiatrist who treats patients with addiction and runs a ketamine therapy company. In clinical settings, he says, people are sometimes given the anti-nausea drug Ondansetron, commonly sold as Zofran, 30 minutes before an injection of ketamine, but for the most part, ketamine-induced dizziness is manageable.

Then there’s fentanyl. It’s impossible to say how much recreational ketamine might contain fentanyl—or might not. But, interestingly, “In a medical setting, ketamine and fentanyl are used together and very safely since they provide supplementary effects,” says Steve Yun, a board-certified anesthesiologist. “They produce better anesthesia and better sedation.” Indeed, studies have shown that ketamine and fentanyl combined are safer than many general anesthetics because, unlike those, ketamine doesn’t slow down your breathing. “The problem with recreational use is that it’s a total crapshoot what you’re really getting,” says Yun. “You have no idea.”

Ketamine might make you dizzy, but it shouldn’t make you so dizzy that you vomit—if that happens, it may be from an opioid. And the only way to be sure is to simply test all of your drugs first. When you’re sure there’s no fentanyl in your supply, you can take anti-nausea medication, like Zofran, about an hour before you take K to avoid the worst effects of the dizziness. If you don’t test your drugs, monitor signs of a potential overdose, like throwing up or being unable to breathe—this happens almost immediately if you’re OD’ing. Narcan is now widely available over-the-counter, so make sure you know how to use it. Most importantly, never take ketamine alone.

When Amir nearly overdosed at the Brooklyn warehouse, his friend carried him to a trash can, where he projectile vomited into a bag. Eventually, he felt OK again, but a security guard kicked them out and asked his friend to take out Amir’s barf bag on their way out. It was, at best, a humiliating situation; at worst, a near-death experience. “I’ve done a lot of different drugs, including ketamine, and I’ve never felt so disoriented and out of control as I did at that moment,” Amir tells VICE. “I’m definitely not gonna do that again for a while.”