Ketamine Therapy Side Effects: What to Expect During Ketamine-Assisted Therapy

Ketamine therapy side effects can sound intimidating when you read a clinical list without context. But when ketamine is given as a carefully dosed IV infusion in a monitored setting, most side effects are temporary, manageable, and closely watched by the medical team.

In ketamine-assisted therapy, the medication is not the whole treatment. The infusion may create emotional distance from painful thoughts, while a therapist helps you prepare and process what comes up afterward.

Table of Contents

• What ketamine-assisted therapy feels like
• Common ketamine infusion side effects
• Dissociation during treatment
• Less common ketamine risks
• How providers improve safety
• Who needs additional screening
• Ketamine therapy side effects: the bottom line

What Does Ketamine-Assisted Therapy Feel Like?

IV ketamine used for mental health treatment is generally administered at a subanesthetic dose, meaning a dose below what is typically used for surgical anesthesia. Ketamine injection is FDA-approved as an anesthetic, while IV ketamine for depression and other psychiatric conditions is an off-label use.1 

People describe a range of experiences during an infusion:

• Feeling light, floaty, or deeply relaxed
• Changes in the sense of time or space
• Vivid imagery, memories, or emotions
• Feeling temporarily separate from the body

The experience can feel unusual without being dangerous. Your team should explain what to expect so unfamiliar medication effects feel less frightening.

Common Ketamine Infusion Side Effects

The most commonly reported acute effects include dissociation, anxiety, nausea, increased blood pressure, headache, dizziness, and fatigue. Research suggests that most are mild, dose-dependent, and temporary, often easing during the observation period after an infusion.2

After a ketamine infusion, you may notice:

• Nausea or an unsettled stomach
• Dizziness or poor balance
• Blurry or double vision
• Headache
• A temporary rise in blood pressure or heart rate
• Fatigue, sleepiness, or mental fog
• Anxiety or emotional vulnerability

Some people feel mostly normal soon afterward. Others feel tired or “off” for the rest of the day. Neither response automatically means something went wrong.

Is Dissociation a Ketamine Therapy Side Effect?

Dissociation means feeling temporarily detached from your body, surroundings, thoughts, or usual sense of self. It may feel like floating, observing yourself from a distance, losing track of time, or entering a dreamlike state.

Dissociation can become uncomfortable. In ketamine-assisted therapy, however, some clients find that it allows them to approach painful material with less fear. An intense experience is not required for treatment to be meaningful.

Preparation, grounding, and support from a trusted clinician can make a significant difference. If you are nervous about losing control, say so before treatment.

Ready to explore whether ketamine-assisted therapy could be a thoughtful next step? Contact us today to schedule a consultation and ask any questions you have. 

Less Common but Serious Ketamine Therapy Risks

Serious reactions are less common, but informed consent should include them. Ketamine can cause clinically meaningful blood-pressure changes. Respiratory complications are more likely with excessive doses, rapid administration, or combination with substances that suppress the central nervous system.1

Additional ketamine therapy risks may include:

• Severe anxiety, agitation, confusion, or an unpleasant psychological reaction
• Worsening mania or psychosis in someone who is vulnerable
• Persistent vomiting or significant blood-pressure elevation
• Misuse, tolerance, or dependence
• Liver or bile-duct injury with recurrent exposure
• Bladder or urinary complications with long-term use or misuse

Long-term psychiatric dosing is still being studied. Bladder injury and dependence are most strongly linked to frequent, high-dose, or prolonged use, but clinics should still ask about urinary symptoms and substance-use history. The FDA recommends baseline and periodic liver testing with recurrent dosing.1

How Providers Reduce Ketamine Side Effects

Safe ketamine care includes medical screening, monitoring, emotional preparation, and a plan for the hours after treatment.3 

Your care team may reduce ketamine side effect risk by:

• Reviewing your medical, medication, and mental health history
• Checking blood pressure, pulse, oxygen level, and symptoms
• Adjusting or stopping the infusion if needed
• Using anti-nausea medication when appropriate
• Providing a quiet, low-stimulation environment
• Monitoring you until you are ready to leave
• Requiring a responsible adult to drive you home

The FDA label advises patients not to drive, operate machinery, or engage in hazardous activities for 24 hours after receiving ketamine.1 Always follow your own provider’s instructions.

Who Should Discuss Ketamine Infusion Risks Carefully?

Extra caution may be needed for people with uncontrolled high blood pressure, significant cardiovascular concerns, active psychosis, a history of mania, certain substance-use disorders, liver problems, urinary symptoms, pregnancy, or breastfeeding.

This does not automatically mean treatment is impossible. It means the decision should be individualized by qualified medical and mental health professionals, not based on a quick online questionnaire.

If traditional treatment has not brought the relief you hoped for, you deserve a careful conversation about appropriate options. Contact our team to learn whether ketamine-assisted therapy fits your history, needs, and goals.

Ketamine Therapy Side Effects: The Bottom Line

Ketamine therapy side effects are real, but the most common ones are usually brief and manageable in an appropriately screened and monitored patient. The goal is not to promise a perfectly comfortable experience. It is to create a setting where physical changes and emotional vulnerability are met with skill instead of panic.

Ketamine-assisted therapy works best when medication, medical safety, psychotherapy, and integration are treated as parts of the same process. If you are ready to explore a different path toward healing, contact us today to take the next step with a team that prioritizes both safety and meaningful therapeutic support.

Footnotes

1. U.S. Food and Drug Administration. Ketalar (ketamine hydrochloride) injection prescribing information. Revised March 2026. 
2. Short B, Fong J, Galvez V, Shelker W, Loo CK. Side-effects associated with ketamine use in depression: a systematic review. The Lancet Psychiatry. 2018.
3. Sanacora G, Frye MA, McDonald W, et al. A Consensus Statement on the Use of Ketamine in the Treatment of Mood Disorders. JAMA Psychiatry. 2017.