While ketamine clears the system of people who take it within one to three days, it can show up on drug tests for longer, depending on whether or not metabolites are left behind. A standard drug screening panel won’t detect ketamine, but specialized tests can. 

It’s possible to detect ketamine in the following ways:

  • Urine test: Up to 14 days after someone uses the drug. There has even been some research showing it can appear in a urine test for more than 30 days after someone uses it. 
  • Hair tests: These can show ketamine use for months after someone’s last dose.
  • Blood test: Usually, this type of test only shows ketamine for up to 24 hours after someone last used it.

Half-Life of Ketamine

The half-life of ketamine is around 45 minutes. This means in a healthy adult, the average elimination time for ketamine is about four hours and 30 minutes. This is an average, so everyone is going to be a little different regarding how long it takes their body to eliminate ketamine

Ketamine does have metabolites that form as the body is processing it, but these have a shorter elimination half-life than the parent drug of ketamine. For most people, within 24 hours of the last dose of ketamine, the majority is out of the body. Within a few days, all of the ketamine should be out of the system of the person taking it.

Factors That Influence How Long Ketamine Lasts in Your System

While eliminating ketamine takes most people’s bodies anywhere from four to eight hours on average, there are individual factors that play a role. 

For example, age, body mass, genetics, hepatic function and overall health all play a role in how long ketamine stays in your system. Ketamine is likely to leave the system of a young, healthy person more quickly than an elderly person. 

Most ketamine is excreted in urine, so someone who is hydrated may get rid of the drug more quickly than someone who isn’t well-hydrated. A person’s metabolic rate is an important factor as well. The faster someone’s metabolism, the more quickly they’re going to eliminate certain drugs such as ketamine.

Also, the higher the dose someone uses of ketamine, the longer it will take the system to eliminate the drug, and how often someone uses ketamine can be relevant.

Other FAQs about Ketamine

  • Is ketamine illegal?

    It’s illegal to possess or use ketamine outside of medical purposes, yet it is often misused recreationally. Ketamine is a Schedule III controlled substance according to the Controlled Substances Act. A Schedule III drug is one that has a potential for physical and psychological dependence. Other Schedule III drugs include anabolic steroids, low-potency opioids, benzodiazepines and other agents.

  • What does a low dose of ketamine do?

    Generally, at lower doses, ketamine effects include: 

    • Numbness
    • Disorientation
    • Changes in sensory perception
    • Hallucinations
    • Increased blood pressure
    • Increased heart rate
    • Higher body temperature
    • Increased respiration

  • What does a high dose of ketamine do?

    At higher doses, ketamine effects can include:

    • Memory loss
    • Physical and psychological distress
    • Paranoia
    • Anxiety
    • Panic
    • Fear

Addiction treatment is available and can be an option for you or your loved one. Contact The Recovery Village to learn more.

Medical Disclaimer: The Recovery Village aims to improve the quality of life for people struggling with a substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare provider.