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Ketamine: Safety, Side Effects, Adverse Reactions, and Contraindications

Ketamine, an N-methyl-D-aspartate receptor antagonist, has many indications including local anesthesia, procedural sedation, pain management, and depression. Ketamine is being used more frequently off-label for treatment of various mood and mental disorders such as anxiety, PTSD, fibromyalgia, complex regional pain syndrome, postpartum depression, obsessive compulsive disorder, etc. Opioids, benzodiazepines, and anti-psychotics are the most commonly used medications for acute control of pain and agitation. Although, they may have a delayed onset and be associated with serious risk such as respiratory depression, low blood pressure (hypotension), and cardiac arrhythmias, all of which may lead to hemodynamic instability and potential death.

In the acute care setting, ketamine is an appealing treatment option given its rapid onset and safety. Given intravenously or intramuscular, ketamine’s onset is within minutes, duration about 30-40 minutes, and very infrequently leads to any respiratory or hemodynamic issues. At Innerbloom ketamine therapy we are often asked about potential side effects, safety, and contraindications for ketamine use. I aim to answer these questions and address these concerns here. I will talk through the process of our treatment protocols and assure you that your safety is a top priority, and we are ready to address any potential issues during your infusions.

The most common side effects associated with ketamine


Some patients may experience nausea at high doses of ketamine especially when associated with movement or intense visual stimuli. Nausea can easily be treated with both oral and intravenous forms of medications. We use Zofran which can be given intravenous for rapid anti-nausea effects. If patients report a predisposition for nausea or had difficulties with this issue during prior infusions, then we can prescribe or premedicate with oral sublingual Zofran. Zofran is a safe, very effective, and the most commonly used medication for the treatment of nausea. While some ketamine clinics may incorporate movement and or visual stimulation such as videos, at Innerbloom ketamine therapy, our protocol is for clients to wear eyeshades and to be still in a comfortable infusion chair.

Less common side effects associated with ketamine


The therapy session is often described as a pleasurable experience, although some sessions may be emotionally difficult. Ketamine may bring out memories or internal issues that you may have consciously or subconsciously concealed or ignored. This is where the healing process takes place, and some level of anxiety is to be expected and normal. Ketamine is a medication with psychedelic properties, thus individuals who have never experienced altered states of consciousness may find these experiences unusual or nothing like they’ve tried before. Some have spiritual or mystical experience, while others report ketamine therapy as being one of the most meaningful and profound experiences in their life.

“But along with the feeling of ineffability, the conviction that some profound objective truth has been disclosed to you is a hallmark of the mystical experience, regardless of whether it has been occasioned by a drug, meditation, fasting, flagellation, or sensory deprivation. William James gave a name to this conviction: the noetic quality. People feel they have been let in on a deep secret of the universe, and they cannot be shaken from that conviction.” ― Michael Pollan, How to Change Your Mind

At Innerbloom Ketamine Therapy, our first approach to anxiety or other strong emotional responses includes guidance and support. Whether that be me (Medical Doctor), Emerald (Nurse Practitioner), or Nina (Registered Nurse), someone is always there during your infusion process. The benefit of the intravenous route of administration is the ability to rapidly stop the infusion if you are having difficulties or the ability to treat your symptoms with IV medications if necessary.

Elevation of heart rate (tachycardia) and elevation in blood pressure (hypertension)

Patients may experience a slight elevation in heart rate and blood pressure which is a normal response and typically does not require any treatment. Additionally, the ketamine experience may be emotional and a psychological response is to be expected, at least to some degree. We continuously monitor your heart rate, blood pressure, and oxygen saturation and have rapid acting intravenous medications to treat any potential concerning elevations of heart rate or blood pressure. Additionally, we can prescribe medication to be used prior to your infusion if you are prone to these reactions.

Rare acute issues or emergencies associated with ketamine

Low oxygen saturations (hypoxia) and laryngospasm

The beauty and benefit of ketamine is that it is rarely associated with any respiratory depression or issues. This is unlike opioids such as morphine or benzodiazepines such as Xanax which can be associated with lowering of breathing rate, shallow breathing, and significant drops in oxygen levels. We continuously monitor your oxygen saturation, and we have an oxygen tank and mask at hand in case you need supplemental oxygen. We do not expect this to happen often, but we are ready if it does. Hypoxia may be more common in patients with underlying pulmonary issues, sleep apnea, smokers, or those who are morbidly obese.

Laryngospasm is a rare experience where the vocal cords suddenly close when taking in a breath, blocking the flow of air into the lungs. The laryngospasm is released by performing a jaw-thrust maneuver which includes pushing both sides firmly inward towards the skull base that should break the laryngospasm within 1-2 breaths. This is exceptionally rare during an infusion although it may be associated with high doses that are pushed rapidly. Our protocol is an IV infusion over 45 minutes rather than rapid administration. An intramuscular route of administration may be offered, although this is given at lower doses and in patients who have considerable experience with ketamine.

Rare long-term effects of ketamine use

Interstitial cystitis

Frequent (multiple doses per day) and high doses (100-200mg per dose) of ketamine often associated with recreational use can lead to a condition termed ketamine-associated cystitis or interstitial cystitis. This is characterized by lower urinary tract symptoms such as lower abdominal pain, painful urination (dysuria), frequent urination, the sensation of needing to urinate more frequently (urgency), inability to urinate, or blood in the urine (hematuria). Complications include impaired kidney function, hardening of the bladder with decreased ability to hold higher volumes of urine, which in rare cases may require surgery.

The proposed mechanism of interstitial cystitis is the direct toxic effect of metabolites of ketamine on cells of the bladder causing hardening and fibrosis that causes structural damage and function of the bladder. Treatment of interstitial cystitis includes cessation of ketamine which may be sufficient for returning bladder to normal function or in worst case scenario procedures or surgery that involves stenting or placement of drainage tubes into parts of the urinary tract system to allow for drainage or urine. Those with a severely contracted and non-functioning bladder may require cystoplasty which involves reconstructive surgery to increase the size of the bladder and improve its ability to stretch and hold urine.

Interstitial cystitis is very unlikely to occur with IV ketamine associated with therapeutic use. IV ketamine is 100% bioavailable, and as such, we use much lower doses. At Innerbloom Ketamine Therapy, infusions are spread out over a course of 4-6 weeks. Given the lower doses and infrequent treatments (as opposed to daily used commonly associated in recreational use), interstitial cystitis is very rare and although it is a possibility, we do not expect to encounter this at IKT.


The list of people who should not receive ketamine infusion therapy is short, although worth mentioning. At Innerbloom Ketamine Therapy, we carefully review your medical history and specifically screen patients for contraindications that include:

  • Active substance-abuse
  • Psychosis or schizophrenia
  • Severe liver disease/failure
  • Significant coronary artery disease
  • Poorly or uncontrolled hypertension

Final thoughts

Ketamine is an effective, rapid, and safe option for the treatment of mood and other mental disorders. Severe side effects or long-term problems associated with ketamine in a therapeutic setting (such as infusion therapy) are rare. More common side effects are anxiety and nausea which are mild and easy to treat. Our staff has significant experience with acute care and after years of working in the emergency room and for life treating situations (trauma surgery), we are comfortable dealing with the worst of the worst. We are prepared for any potential side effects and are more than ready to ensure your safety during your entire experience at Innerbloom Ketamine Therapy.

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