What are Ketamine’s Short and Long-Term Side Effects?

Medically reviewed by 
Kristin Arden, PMHNP-BC
Published on 
March 19, 2021
Updated on 

Any good faith and informed exploration of ketamine and ketamine treatment should include a list of potential side effects that a client may experience. There are both neurobiological and phenomenological side effects that may arise in the short-term immediately after a session, or longer-term through persistent use.

It’s important for practitioners, clinicians, and clients working with this medicine to be informed of these potential side effects, and their frequency and severity. This helps to make informed decisions about moving forward with ketamine treatment and psychedelic therapy programs.

Ketamine is a medication used for a variety of purposes including anesthesia during surgery, pain relief (analgesia), and treatment of mental health concerns, meaning it has the ability to act on multiple areas of the body. When used to treat mental health conditions, it is acting on the brain.

However, during these treatments, ketamine impacts other physiological functions as well. This can result in objective and subjective side effects, even with a single treatment. These effects are sometimes referred to as "body load," or physical sensations brought on by the ketamine and other similar substances which may be difficult to describe. This article will explore both of these categories of side effects from both a short-term and long-term perspective. Let's begin by defining what the term "side effect" means.

Defining “Side Effects”

In medical terms, the term "side effect" is used to describe an unwanted or unintended effect of a drug. Although the term is predominantly used to describe adverse effects (mild, moderate, to severe), there are some side effects that can be beneficial.

Using this definition, you can say that the antidepressant and anxiolytic properties are a beneficial side effect of ketamine since its initial intended use was as a surgical anesthetic. Using this example, we can see that not all side effects are negative. However, this article will address the adverse side effects possible from consuming ketamine.

If you would like to explore the positive and beneficial aspects of ketamine treatment for mental health, check out our resources addressing anxiety, depression, and treatment-resistant depression directly.

Side effects can differ in severity, duration, and manner of effect — neurobiological and psychological. Some side effects are simply minor developments that fade quickly after a session, while less common but more severe side effects may require additional attention or care.

Clinical Administration vs. Recreational Use: A Distinction

Before exploring the neurobiological and psychological side effects in more detail, it is important to draw a critical distinction between the method of administration and how this relates to side effect development and prevalence. Namely, the context in which the client is receiving ketamine.

Most of the literature surrounding the side effects of ketamine looks at these effects under the context of habitual recreational use with or without addictive behavior patterns present. These are side effects that can arise from frequent use of unknown quantities, perhaps with increasing amounts of ketamine, for a sustained period of time.

When medications are taken in a manner, dose, or environment other than what is prescribed by a clinician, the potential for adverse side effects increases, as can the severity of side effects.

When working with ketamine, doing so in a structured treatment program alongside trained and experienced clinicians is of the utmost importance. The included protocols are set up to protect client safety, and ensure individuals have the support, care, and guidance that is necessary to work effectively with these medicine experiences.

Side effects are still present in clinical and therapeutic contexts, but the structured support environment is more conducive to modify the treatment plan should side effects arise, if continued therapeutic work is recommended.

If you are currently working within a ketamine treatment protocol or psychedelic therapy program, it is important to inform your care team of any concerns, questions, or comments you have surrounding your experience and the emergence of anything you may consider an adverse side effect. You have a team there to support you, and it’s beneficial to work with their domain expertise and experience throughout these programs.

Short-Term Neurobiological Side Effects

Beginning with the neurobiological side effects of ketamine, there are a number of side effects that may emerge during a treatment session, or in the few hours after a session.

Since ketamine acts on the nervous system as a whole, it is important to block off sufficient time after treatments to allow for recovery. It’s recommended to give your body the space and time it requires to process and metabolize the medicine.

Some short-term neurobiological side effects of ketamine may include:

  • Elevated blood pressure and increased heart rate
  • Nausea, occasionally with vomiting
  • Drowsiness
  • Disorientation and confusion
  • Headache

There are steps involved in the preparation and post-session suggestions to help manage and mitigate the potential of these side effects as much as possible.

For example, the dissolvable sublingual tablets used in Mindbloom's treatment protocol are not meant to be swallowed, nor the saliva that they dissolve into. Swallowing the dissolved tablets and saliva greatly increases the potential for neurobiological side effects, which may include increased drowsiness, dizziness, and/or nausea.

Knowing this information is half the battle. If you are aware of the potential for these side effects to emerge, it is much easier to prepare beforehand and be ready for them if they do emerge. Rest and stillness are helpful in dealing with many common short-term neurobiological side effects that do emerge.

As the experience will be unique for each client, it’s important to be informed of side effects beforehand. Equally important is having someone to support and watch out for you during and after the session, and having plans in place that were coordinated with the assistance of a clinical care team to remedy these effects if they do arise. Some individuals may experience multiple side effects, while others may experience few or none at all.

If you have any concerns about this, or feel like you want extra support in the sessions, open this dialogue with your clinical care team so that you feel safe and supported going into the treatment session — an important feature to create safe and powerful experiences.

Long-Term Neurobiological Side Effects

As mentioned before, if you are working with a professional clinical care team, the treatment protocols, including specific session dosages, and frequency of your sessions will help to avoid any long-term adverse side effects.

The side effects listed below have emerged largely in the context of frequent habitual recreational use, with or without associated addictive patterns and behaviors. Ketamine does impact the body, particularly the kidneys, and it is important to be aware of this beforehand.

Some potential long-term physiological side effects of ketamine use include:

  • Kidney injury or damage
  • Trouble or pain with urinating
  • Substance dependence and tolerance
  • Baseline increase in heart rate
  • Baseline increase in blood pressure
  • Respiratory depression
  • Possibility of seizures

Given the potential side effects of long-term ketamine use, it is important to follow the prescriptions and protocols of your treatment program, as these are developed and prescribed to safely avoid these long-term effects while still providing effective and therapeutic experiences.

If any concerns or questions emerge throughout your course of treatment, please check in with your care team to go over these in detail. Treatment feedback is important and allows your clinical care team to make informed and safe decisions regarding your program.

Short-Term Psychological Side Effects

Ketamine can also have psychological side effects — those that emerge at the level of emotions, thought patterns, and waking conscious state.

There are both short-term and long-term experiential side effects that may occur as well. Both working with trained professionals in a safe context, and adequate preparation of set and setting help to manage and mitigate the emergence or the severity of potential side effects.

Some short-term psychological side effects that can arise during or just after a treatment session may include:

  • Stress from processing emotions/memories
  • Disconnection from existing life
  • Anxiety, depression, or worsening of these
  • Increase in irritability/fragility

As a consciousness-altering agent, ketamine treatment can have a profound and important impact on your mental health. However, if not managed safely and effectively, these experiences can also surface unintended consequences.

If you have a significant emotional experience in the session, it may take some time outside of the planned treatment time to process fully. This may cause some short-term emotional stress. Experiences that are new to you may occur: out-of-body moments, visual or auditory hallucinations, or disconnection from thoughts and the body. This can be alarming for some.

As you process the experiential information, there may be periods of emotional lability or confusion. If this does happen, work with your support systems, take time to rest, and allow the medicine to metabolize fully. The effects should decrease and resolve as the medication is broken down and exits the body.

Long-Term Psychological Side Effects

Continued or frequent use of ketamine can lead to long-term changes to your brain, resulting in altered cognitive abilities and mental health.

Again, research suggests that these side effects are predominantly seen in the content of chronic recreational use with or without addictive behaviors present, and can be mitigated and managed by working with your clinical care team and taking the medication as prescribed.

Some potential long-term psychological side effects may include:

  • Degraded memory recall/storage
  • Lowered subjective sense of wellbeing
  • Changes in sleep habits

Following the treatment protocols of an experienced clinician should prevent long-term side effects like those mentioned above from occurring. This is because your clinician will likely require periodic appointments to check for efficacy of treatment and possible side effects that you may be experiencing before prescribing more Ketamine.

Having an informed understanding of the medicine, of the potential therapeutic benefits and adverse side effects that exist, and working within your therapeutic container, will all serve to provide safe, effective, and powerful experiences.

How to Manage/Mitigate Potential Side Effects

Like any medicine, ketamine comes with its own associated neurobiological and psychological side effects, some of them healing and welcome, some of them potentially distressing and adverse.

Fortunately, ketamine has been researched for several decades, initially gaining FDA approval in 1970 as a fast-acting anesthetic. Since then it's uses as an analgesic and its mental health benefits have been studied in depth. It is currently the most well-studied psychedelic medicine available for prescription by a clinician. From these studies a number of best-practices and safety protocols have emerged.

If you have any concerns about the potential side effects that can arise, here are a few steps you can take to help mitigate or manage these:

  1. Talk to Your Clinician: This is always the first step. If you have any concerns or questions, bring this up with your clinical care team so that all parties are informed. This is not something you have to, nor should you, figure out and manage by yourself. You have a care team supporting you through these experiences, your safety and addressing side effects is one of the things they are here to help with.
  2. Follow the Program Protocols: All of the recommendations, requirements, and procedures that are part of your treatment protocol are there for a reason. Nothing is redundant. Requirements such as not eating a few hours beforehand, having a peer monitor present throughout the experience, and recommendations like preparing yourself physically and mentally beforehand, and setting clear intentions are in place to help provide safe, effective, and powerful healing experiences. Follow the recommendations that your care team provides.
  3. Set & Setting: Preparation is important, particularly for powerful healing experiences like these. Taking the time to prepare beforehand, ensuring that you are in an open and welcoming mental space. Make sure that your physical environment is set up to be comfortable and supportive, that you have clear intentions, and are in a state of trust and openness. These all help the process, ensuring you can manage any physical side effects and are well-equipped to handle any side effects that may arise in the sessions.
  4. Take Care of Your Health: There is a lot that you can do outside of the sessions themselves to help mitigate or manage the impact potential of side effects. Take care of your physical health in all areas, and welcome and explore your emotions. The more grounded and fit your mind and body are coming in, the more you can receive the medicine and welcome anything that wishes to arise throughout the program.
  5. Trust, Let Go, Be Open: A timeless mantra in the psychedelic therapy world, trust that the experience will bring you what you need. Let go of your expectations or requirements for the sessions, and be open to the nature of the experience and to the way the medicine is experienced.

Following These Steps Will Help You Fully Prepare

These steps are not bulletproof guarantees that in following them you will not experience any potential side effects. These steps help you to fully prepare as best as possible, so that you have resources available to you if any of these do begin to arise during or after the dosing sessions.

Work with your team, work with yourself, follow the recommended guidelines, and you will be more likely to have the safe, effective, and powerful experiences that you embarked on this healing journey for.


This article is for informational purposes only and is not intended to be a substitute for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. If you are in a life-threatening situation, call the National Suicide Prevention Line at +1 (800) 273-8255, call 911, or go to the nearest emergency room.

Important FDA Safety Information

Ketamine is not FDA-approved for the treatment of depression or anxiety. Learn more about off-label uses here.

Side effects of ketamine treatment may include: altered sense of time, anxiety, blurred vision, diminished ability to see/hear/feel, dry mouth, elevated blood pressure or heart rate, elevated intraocular or intracranial pressure, excitability, loss of appetite, mental confusion, nausea/vomiting, nystagmus (rapid eye movements), restlessness, slurred speech, synesthesia (a mingling of the senses).

Do not proceed with ketamine treatment if any of the following apply to you:

  • Allergic to ketamine
  • Symptoms of psychosis or mania
  • Uncontrolled high blood pressure
  • CHF or other serious heart problem
  • Severe breathing problem
  • History of elevated intraocular or intracranial pressure
  • History of hyperthyroidism
  • Other serious medical illness
  • Pregnant, nursing, or trying to become pregnant

Ketamine has been reported to produce issues including, but not limited to, those listed below. However, lasting adverse side-effects are rare when medical protocols are carefully followed.

While ketamine has not been shown to be physically addictive, it has been shown to cause moderate psychological dependency in some recreational users.

  • In rare cases, frequent, heavy users have reported increased frequency of urination, urinary incontinence, pain urinating, passing blood in the urine, or reduced bladder size
  • Ketamine may worsen problems in people with schizophrenia, severe personality disorders, or other serious mental disorders.
  • Users with a personal or family history of psychosis should be cautious using any psychoactive substance, including ketamine, and discuss potential risks with your MindBloom® clinician before proceeding with treatment.
  • The dissociative effects of ketamine may increase patient vulnerability and the risk of accidents.

To promote positive outcomes and ensure safety, follow these ketamine treatment guidelines:

  • Do not operate a vehicle (e.g., car, motorcycle, bicycle) or heavy machinery following treatment until you’ve had a full night of sleep
  • Refrain from taking benzodiazepines or stimulants for 24 hours prior to treatment
  • Continue to take antihypertensive medication as prescribed
  • Avoid hangovers or alcohol intake
  • Refrain from consuming solid foods within 3 hours prior to treatment and liquids within 1 hour prior to treatment
  • Ketamine treatment should never be conducted without a monitor present to ensure your safety

Try Ketamine Treatment

If you're ready to explore ketamine treatment yourself, you can start the process through the link below.

Get StartedGet Started