What Does Ketamine Do?

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Medically reviewed: Paloma Lehfeldt, MD
a woman participating in ketamine therapy

How Does Ketamine Work & How Can it Help Me?Ketamine was developed as an anesthetic in 1962(1) and was approved for medical use by the FDA in 1970. Ketamine has been used as a general anesthetic in hospitals, clinics, and surgical suites for decades. Well known for its safety profile and low risk of abuse, ketamine has been the popular anesthetic for pediatrics, eldercare, and in circumstances where patients may be at risk of respiratory failure.

What Does Ketamine Do to Your Brain? Ketamine can be used for mental health conditions due to its impact on the brain’s glutamate system. Glutamate is an important neurotransmitter thought to be involved with the regulation of mood. Ketamine achieves this by altering how glutamate interacts with the NMDA (N-methyl-D-aspartate) receptor.(2)

Neurotransmitters like glutamate may play a vital role in how some conditions, such as depression or anxiety, manifest. Altering glutamate levels in the brain may be able to decrease the severity of some symptoms.(3)

Glutamate, and thus ketamine, also has another interesting effect on the brain. Glutamate may be partially responsible for improving the brain’s neuroplasticity or the ability of the brain and nervous system to change its activity, structure, and function. The more neuroplastic your brain is, the easier it is for you to think about things in fresh ways. 

By improving your capacity to consider your life circumstances in a new light, it’s possible that ketamine therapy can help you break out of endless cycles and stubborn modes of thinking, such as painful ruminating (repetitive, intrusive thoughts). This new outlook on things like past experiences or trauma may help you process your internal and external life in healthier ways.(4)

What Does Ketamine Feel Like?Ketamine can produce a range of physical and mental sensations. For example, many patients report that ketamine makes them feel as if they are able to view themselves and their condition from an outside perspective. This is known as dissociation, a sense of feeling detached from your mind and body. Ketamine may also reduce some negative emotions, such as fear and dread. At low doses, ketamine can be used as a powerful psychotherapy tool because it can overcome rigid defense mechanisms that make it difficult to discuss personal trauma.(5)

In higher sub-anesthetic doses, ketamine can exhibit potent non-traditional psychedelic effects. These can range from small visual distortions like seeing lines, geometric patterns, or bright colors to receiving valuable insights and spiritual experiences. Ketamine can also cause blurred vision.(6)

In rare cases, ketamine can bring on a dissociative event known as a K-hole. Experiencing a K-hole can be frightening, especially if you aren’t prepared for it. The informal term “k-hole” is commonly used to describe a dissociative event for which one is unprepared. This underscores the importance of understanding ketamine’s mechanism of action and using ketamine in the proper therapeutic setting. This is known as “set and setting,” with “set” referring to your mindset and “setting” being your physical and social environments. These factors often profoundly influence the type of experience you have.

How Long Does Ketamine Last?Depending on the method of administration, the effects of ketamine can last anywhere from one to four hours. Generally, the onset of intravenous (IV) ketamine is the most rapid, and oral administration is the slowest. See below for the various onset of action and duration of treatment:(7)

PO (Taken by mouth, i.e., Oral Lozenge, Pill, or Tablet): Onset up to half an hour. Ketamine can be felt anywhere from one to two hours. 
IM (Intramuscular): Onset three to five minutes. Effects last two to four hours.
IN (Intranasal Spray): Onset five to ten minutes. The medication’s effects can last for up to three hours.
PO (Taken by mouth, i.e., Oral Lozenge, Pill, or Tablet): Onset up to half an hour. Ketamine can be felt anywhere from one to two hours. 

How Long Does Ketamine Stay in Your System?

Ketamine is metabolized quickly and thus has a relatively short half-life. Generally, the amount of active ketamine in your system will be reduced by 50% within two and a half hours. Ketamine can be detected in urine, blood, saliva, and hair for varying amounts of time.(8)

Saliva: 24 Hours
Blood: 72 Hours
Urine: 14 Days
Hair: 30-120 Days

What Are The Side Effects of Ketamine?Like many other medications, ketamine does have side effects that can occur during treatment and may extend beyond the treatment duration in some individuals, but this is uncommon. Some of ketamine side effects include:(9)

  • Nervousness
  • Tension
  • Rapid Heartbeat
  • Shallow or Rapid Breathing
  • Shallow or Rapid Breathing
  • Insomnia
  • Feelings of Fear
  • Avoidance Behavior
  • Over Stimulation
  • Dissociation
Ketamine may not be right for individuals with some mental health conditions, such as schizophrenia or high blood pressure. You should always consult a medical provider to determine if ketamine is right for you. Ketamine can impact everyone differently. 

How to Get Ketamine TherapyIf you think ketamine is right for you, you should consult with a licensed ketamine provider. Ketamine treatment can be administered at home or in a clinical setting. Learn how to find ketamine treatment near you

a woman during ketamine treatment

Where to Find
Ketamine TreatmentLocate outpatient ketamine clinics and at-home ketamine service providers in the U.S. that offer care for pain, depression, anxiety, PTSD, OCD, and addiction.