Safety in Ketamine Treatment

Ketamine therapy has become an important option for people living with treatment-resistant depression, PTSD, and related mental health conditions. For many patients who have struggled for years with limited success from traditional medications, ketamine can offer relief that feels transformative.

At the same time, it is important to talk openly and honestly about safety. IV ketamine is generally considered a safe medication when administered in a clinical setting, but like any medical treatment, it is not perfectly risk-free. Understanding both the benefits and the risks, and how those risks are managed, is essential for patients, clinicians, and the broader mental health community.

Recent research and new data from Ember Health help clarify what those risks actually look like in practice.

Ketamine Is Safe— But Not Perfectly Safe

The best available research on serious medical adverse events in ketamine treatment was published in 2023. That study found that serious medical adverse events occur in about 0.1% of ketamine treatment sessions— approximately one in every 1,000 infusions.

For an individual patient, that risk may appear small. Many people living with severe depression or suicidal ideation understandably decide that the potential benefits outweigh this low probability of complications.

However, from a population health perspective, even rare risks matter. When tens of thousands of treatments are delivered across clinics, statistically those safety events will occur. That reality underscores the importance of proper medical protocols, monitoring, and trained clinicians present during treatment to ensure people stay safe, even when these events happen.

This is one of the reasons the FDA issued guidance in 2023 stating that ketamine should only be accessed in medically supervised settings. The agency notes that serious complications— including breathing suppression, cardiovascular instability, and other emergencies— can occur and require rapid clinical intervention.

In other words, the risk may be small, but the consequences of not being prepared can be serious.

Understanding Adverse Events in Ketamine Treatment

When clinicians talk about safety in ketamine treatment, it is important to distinguish between different types of events. Not every side effect carries the same level of concern.

In clinical practice, adverse events are generally categorized into three levels:

Mild Events

These are relatively common side effects that typically respond quickly to simple interventions. These events may require supportive care or occasionally, medications, but they rarely require stopping treatment.

Examples include:

• Nausea
• Headache
• Dizzyness

Moderate Events

These occur less frequently and may or may not require stopping the infusion depending on severity. Clinicians may pause treatment, adjust dosing, or administer medication depending on the situation.

Examples include:

• Vomiting (emesis)
• Tachycardia (elevated heart rate)
• Hypertension (increased blood pressure)

Serious Events

These are rare but potentially dangerous complications that require immediate medical response and discontinuation of treatment. These are the kinds of events referenced in FDA warnings and in the scientific literature when discussing serious adverse events.

Examples include:

• Apnea (temporary cessation of breathing)
• Hypotension (low blood pressure)
• Laryngospasm
• Anaphylaxis
• Seizure
  
  

What 32,018 Infusions Reveal About Real-World Safety

At Ember Health, patient safety is a central focus of clinical care. Every infusion session is monitored by a clinician, and detailed clinical notes are recorded for each visit.

To better understand the safety profile of ketamine treatment in practice, we conducted a large internal review of 32,018 infusions delivered to 2,174 unique patients. These findings were recently presented at the American Society of Ketamine Practitioners (ASKP) conference in Austin, Texas in January 2026, and are being prepared for publication with collaborators at Harvard Medical School and Mass General Brigham.

The results provide one of the largest real-world datasets on ketamine infusion safety.

Most sessions are calm and uneventful

Across all treatments:

• 95% of infusions involved patients resting quietly and comfortably without any clinical intervention.

This is consistent with the general clinical experience of ketamine therapy: most sessions proceed without incident.

Psychological events are most common

Some patients experience emotionally challenging moments during the altered state produced by ketamine.

• 3.94% of sessions involved a behavioral or psychological event.

These events might include anxiety, agitation, or emotional distress during the session. They are typically managed through clinician support and reassurance.

Medical event instances match prior research

Medical events occurred in 0.95% of sessions.

Most of these were minor issues that clinicians were able to manage quickly.

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What Happens When Medical Events Occur?

When a medical event occurred during treatment, clinicians at Ember Health have responded in different ways depending on severity. Across all visits:

Importantly, no cases required emergency resuscitation equipment, and most situations were resolved with physician directed medication, treatment, and support.

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The Most Common Medical Events

The most frequent issues clinicians intervened for during an infusion were:

It is important to note that these numbers represent events serious enough that clinicians decided intervention was necessary. Mild symptoms that resolve on their own are not included. As an example, nearly 25% of our patients report that they feel some nausea from treatment, though only 0.5% were nauseous enough that a clinician needed to intervene during the infusion itself.  

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Medications Used to Manage Side Effects

When symptoms did occur, clinicians used several common medications to help stabilize patients.

Antiemetics (for nausea or vomiting)

• Used in 201 visits (0.63%)
• Affecting 7.22% of patients

Beta-blockers (for tachycardia or hypertension)

• Used in 80 visits (0.25%)
• Affecting 2.81% of patients

Benzodiazepines (for anxiety or agitation)

• Used in 9 visits (0.028%)
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These medications allow clinicians to quickly manage symptoms and help patients remain comfortable.

Preventing Side Effects Before They Start

In many cases, clinicians anticipate side effects based on a patient’s prior experiences and provide preventive medications before treatment.

Common pre-treatment medications included:

Interestingly, patients who received nausea prevention medication showed higher observed nausea rates in the data. This does not mean the medication caused nausea. Rather, clinicians typically administer these medications to patients who already have a history of nausea during treatment.

Serious Adverse Events

The study also tracked serious adverse events, defined according to FDA criteria. These include events that could lead to life-threatening complications or require emergency intervention.

Examples recorded included:

• Palpitations
• Hypoxia
• Tachypnea
• Dyspnea
• Hypotension
• Arrhythmia
• Persistent hypertension

Across the entire dataset:

• Serious adverse event rate: 0.06% per visit
• Serious adverse event rate: 0.87% per patient

This translates to roughly:

• 1 serious adverse event for every 1,685 visits
• 1 serious adverse event for every 115 patients

Six treatments resulted in sending patients to the emergency room to be evaluated after in-office intervention by an emergency trained physician. Importantly, all six cases resolved, no deaths occurred, and no cases of lasting harm were identified.

Why Monitoring Matters

One key lesson from this data is simple: rare risks still occur when enough treatments are delivered.

In a clinic providing thousands of treatments per year, clinicians must assume that rare complications will eventually arise. The question is not whether they can happen, but whether the team is prepared to manage them safely.

At Ember Health, several safety protocols are designed specifically for this purpose:

• 1:1 clinician-to-patient monitoring
• Continuous observation during the infusion
• Cardiac and vital sign monitoring when needed
• Standard operating procedures for every known side effect
• Emergency equipment such as AEDs and Ambu bags on site
• Clinicians trained to intervene medically if needed

This structure allows clinicians to respond immediately when a patient needs support.

Route of Administration and Safety

Another important consideration is how ketamine is administered.

In this study, treatments were delivered via intravenous infusion, with doses between 0.5 and 1 mg/kg administered over 40 minutes.

IV ketamine has several advantages in terms of safety:

• 100% bioavailability, meaning the medication reaches the bloodstream directly
• Precise dose control
• Ability to stop or adjust the infusion immediately if needed

Other routes of administration— such as oral, nasal, or intramuscular ketamine— often require higher total doses because they are absorbed less efficiently. Higher dose exposure increases the risk of the adverse events listed throughout this article.

What This Means for Patients

For people considering ketamine therapy, the takeaway is reassuring but nuanced.

Ketamine treatment, particularly when administered intravenously in a clinically monitored setting, appears to have a strong safety profile. Most sessions proceed without incident, and the most common issues, such as nausea or elevated heart rate, are manageable with standard medications.

However, the risk is not zero. Rare events do occur, and when they do, medical supervision matters.

Patients should feel comfortable asking clinics questions such as:

• Is a clinician present during the entire session?
• What monitoring equipment is available?
• What protocols are in place for adverse events?
• Are clinicians trained to respond to medical emergencies?

These are important elements of responsible care.

Safety as a Responsibility of the Field

Ketamine therapy is a rapidly growing area of mental health treatment. With that growth comes responsibility.

Clinics, researchers, and providers must ensure that the field maintains the trust of patients and the broader medical community. That trust is earned through transparency, rigorous data collection, and a commitment to patient safety.

The findings from over 32,000 monitored infusions with Ember Health reinforce a clear message:

Ketamine can be delivered safely, but it should be delivered with appropriate medical oversight.

At Ember Health, that commitment to safety includes continuous monitoring by appropriately trained clinicians, standardized protocols, and ongoing research collaboration with academic partners.

For patients seeking relief from severe depression and related conditions, this combination of innovation and careful medical practice is essential to ensuring that new treatments remain both effective and safe.

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To view the full ASKP presentation where Dr. Nico Grundmann presented this safety data, see the video below. Other presentations in the panel include colleagues speaking from Harvard Medical School, Mass General Brigham and Baylor College of Medicine.

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