Be Aware of These Short- and Long-Term Ketamine Effects

Medically Reviewed

Ketamine was once used as an animal sedative, but today it’s studied as a potential treatment for a variety of ailments like depression, a pediatric anesthetic, chronic pain, and treatment for severe asthma. Depression and chronic pain are particularly troubling problems for doctors and clinicians today.

Depression is a mental health problem that affects about 322 million people worldwide, according to the Anxiety and Depression Association of America. In many cases, patients may be resistant to traditional treatment options, or they may have uncomfortable side effects. Depression rates have also been on the rise in the past few years in the United States.

Chronic pain is another issue that plagues patients and leads to complicated consequences. Chronic pain is treated with a variety of analgesic medicines like opioids. Opioids are effective but can lead to chemical dependence and addiction. While the country is in the middle of a growing epidemic of opioid addiction and overdose, the search for viable pain relief alternatives is becoming more urgent.

However, ketamine isn’t without its drawbacks. The drug’s addictive potential has led to its abuse by people who are looking for a euphoric or relaxing high. In 1999, ketamine was federally classified as a Schedule III substance, which means that the drug has a potential for abuse and moderate physical addiction, but it also has some currently accepted medical uses.

Ketamine is fairly safe when a medical professional administers it, but it can come with uncomfortable side effects. Dangerous reactions can occur when you take high doses, especially without medical supervision.

Learn more about ketamine and its potential for short- and long-term effects.


Ketamine can produce feelings of relaxation, euphoria, and dissociation. In clinical doses, users can experience an effect called dissociative hallucination, which is more commonly known as an out-of-body experience. While that may conjure up images of floating above your body like a cartoon character, it may be more akin to a cognitive ability to look at your own thoughts and experiences from an objective point of view. It’s a strange psychoactive effect, but it may have some therapeutic benefits when administered safely.

People with depression, anxiety, and trauma disorders can benefit from this effect because it allows them to process experiences and emotions from an outside perspective. However, ketamine has not yet been approved as an antidepressant in the United States. Dissociation is also an effect that some people seek out in recreational drug use.

At higher doses, it can cause psychedelic dissociative effects and euphoria. In some cases, people experience what is called the “K-hole,” which is an intense dissociative experience. During bad trips, people can experience panic and dysphoria that can do, at least temporary, psychological harm.

Short-Term Effects of Ketamine

Ketamine can cause some short-term effects and side effects, even when it’s used in a medical setting. However, side effects are more likely to lead to dangerous consequences when the drug is used illicitly and in high doses. Common side effects will be consistent with other sedative drugs. You may feel drowsy, sleepy, and listless. At anesthetic doses, you might have hallucinations or delirium, but these effects are generally rare.

Ketamine can also affect the heart, causing abnormal rhythms, a change in heart rate, or a change in blood pressure. In an otherwise healthy person, heart-related symptoms may be mild, but it’s important to have access to medical monitoring to ensure safety. In people with heart conditions, ketamine can lead to dangerous complications.Because ketamine has some nervous system depressing effects, high doses can slow or stop breathing, but the threat of this happening is lower than in opioids. However, high doses of ketamine can also cause vocal cord spasms that can block breathing and requires immediate medical intervention. This adverse reaction is rare and may only occur with intravenous injection.

Other Short-Term Effects of Ketamine Use Can Include:

  • Nausea
  • Appetite loss
  • Vomiting
  • Red or rashy skin
  • Double vision
  • Involuntary eye movements
  • Tunnel vision
  • Increased eye pressure

In high doses, some people may experience tremors and movements similar to tonic-clonic seizures, which can be dangerous. This drug has a unique set of effects and adverse reactions that make it relatively safe with medical supervision and expertise but very dangerous when used illicitly or recreationally.

Long-Term Effects of Ketamine

Ketamine can also cause adverse effects with long-term use. Many of the most severe adverse effects of ketamine come was a result of long-term use and abuse. Studies show that it can harm the brain, including in your memory and overall cognitive functioning.

In 1989, a psychiatry professor named John Olney studied the effects of ketamine on rat brains and found that it caused a specific type of brain damage called Olney’s lesions. He found that it caused the same damage as other dissociative drugs such as phencyclidine (PCP).

Olney’s lesions are a type of neurotoxicity that affects NMDA receptor antagonists. However, studies in rats don’t always mean that humans would be affected by a drug in the same way.

Still, other evidence shows that ketamine can impair brain function. A 2004 study examined the long-term effects of ketamine on something called source memory, which is the memory of the source of information. In other words, source memory is your recollection of a time, place, or source of something you learned.

The study examined 40 people, 20 of whom were ketamine users. They found that the ketamine users had an impaired source memory and concluded that repeated ketamine use could lead to chronic memory impairments.

Case reports also suggested that repeated ketamine use could affect the liver. Use in chronic pain relief and in recreation can lead to toxicity in the urinary tract and the liver.

Ketamine can also lead to substance use disorders caused by chemical and psychological dependence. Ketamine can produce euphoric and dissociative highs when used in large doses. However, the high is short-lived partly because of the drug’s short elimination half-life at two to three hours. Depending on how you take the drug, its effects can last between 45 minutes and six hours.

However, you may not be feeling euphoria for very long. Drugs that cause brief highs sometimes encourage binging, which can lead to long-term effects and potentially deadly overdose. Dependence can also lead to withdrawal symptoms like agitation, confusion, nausea, rage, tremors, and even seizures. If you believe that you or a loved one has developed a substance use disorder involving ketamine, it’s important to seek treatment as soon as possible. Addressing a substance use problem early can help you avoid some of the most severe and long-lasting consequences.

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