8 Ketamine Side Effects to Know About When Using It for Depression

It can be extremely challenging if you’re struggling to find an antidepressant that helps your depression symptoms. If you’ve tried many antidepressants but they aren’t working, you may have treatment-resistant depression.

There are a few options for managing treatment-resistant depression. One unique option is ketamine (Ketalar), an injectable medication that’s FDA approved as a surgical anesthesia medication. At lower doses, ketamine is used off-label for treatment-resistant depression. But this comes with risks. Though it can rapidly improve depression symptoms, ketamine side effects are also possible.

Good to know: Spravato (esketamine) is a ketamine-based nasal spray. It’s FDA approved as an add-on treatment to traditional antidepressants for people with treatment-resistant depression or depression with suicidal thoughts or behavior. We’ll focus on intravenous (IV) ketamine in this article, but another GoodRx article covers Spravato side effects in depth.

Ketamine side effects at a glance

Ketamine side effects usually go away within 4 hours. But its antidepressant effects may last several weeks with repeat doses. 

Common/mild ketamine side effects include:

• Drowsiness

• Dissociation (feeling disconnected from your thoughts and surroundings)

• Dizziness

• Disorientation

• Nausea and vomiting

• Temporarily increased anxiety

• Numbness

• Blurred vision

• Difficulty speaking

Rare but serious side effects may include:

• High blood pressure

• Heart problems

• Trouble breathing, leading to death in rare cases

• Hallucinations

• Loss of consciousness

• Dependence and misuse

Serious ketamine side effects are less likely with doses used in depression. They’re more likely with higher doses of ketamine used for anesthesia. Still, ketamine has significant risks to know about. We’ll dive deeper into eight of these side effects below.

Good to know: Ketamine isn’t recommended during pregnancy. And ketamine hasn't been studied for depression in adolescents. So this article is referring to side effects of ketamine use in non-pregnant adults only.

1. Dissociation

At higher doses, ketamine is used as an anesthesia for anything from small procedures to major surgeries. This means it causes sedation or complete loss of consciousness. Dissociation can occur with the lower doses of ketamine used for depression. This is a trance-like state of feeling disconnected from your body or the world around you.

You might start feeling strange or woozy as ketamine enters your system. Hallucinations, numbness, and temporarily losing the ability to speak are also possible. This is part of the reason your healthcare provider will monitor you for a few hours after receiving ketamine. By the time you leave, you should no longer be feeling any dissociative effects.

Arrange for someone to drive you home after your ketamine treatment. Having a support person to stay with you is a good idea, too. If you have any unusual experiences or still feel strange the next day, let your provider know.

2. Drowsiness

Drowsiness is one the most common side effects of ketamine. So it’s a good idea to take it easy for the rest of the day following your ketamine treatment. This includes avoiding activities that require alertness, like driving or caring for a small child.

If you take other medications that cause drowsiness, excessive sleepiness may be more likely. Give your healthcare provider a complete list of all the medications you take before receiving ketamine. This will help them check for ketamine interactions that may worsen drowsiness.

3. Dizziness

Many people report dizziness after receiving ketamine. Dizziness is temporary, but be careful to avoid falls and injuries. Some tips include:

• Make sure your walkways at home are cleared of tripping hazards. 

• Consider having someone stay with you the day you have treatment. They can help you get around and make sure you feel steady on your feet. 

• Take your time changing positions (like standing up) or changing direction (like turning around while walking). These movements can provoke dizziness spells.

• Stay well hydrated. Dehydration can contribute to dizziness.

If dizziness from ketamine doesn’t improve while in your healthcare provider’s office, let your provider know. They may want to monitor you for longer before you go home.

4. Nausea and vomiting

Nausea is one of the most commonly reported side effects of ketamine. Your healthcare provider will likely advise you to avoid eating and drinking in the hours before your infusion to help prevent nausea and vomiting. The specific timing may vary by clinic. 

If you experience vomiting from ketamine, your healthcare provider may recommend a medication to help, such as ondansetron (Zofran). Or they may have you take the medication in advance of your ketamine dose if you’re prone to feeling queasy.

It’s a good idea to have foods or drinks that usually settle your stomach available at home after your ketamine treatment. And make sure to stay hydrated. Dehydration can make nausea worse. 

5. Increased blood pressure

Ketamine can raise your blood pressure. Changes in blood pressure are usually minor, but they’re more likely with higher doses. And larger increases in blood pressure might be possible if you receive ketamine with other medications that increase blood pressure or if you have uncontrolled high blood pressure already.

Your medical provider will check your vital signs before, during, and after your ketamine dose. If your blood pressure is too high, they may delay ketamine treatment or give you medication to bring it down. Up to 20% of people receiving IV ketamine for depression may require blood pressure medication during their infusion.

Working with your healthcare provider to manage your blood pressure before ketamine treatment is important. Extremely high blood pressure can cause organ damage. Get medical help immediately if you experience chest pain, trouble breathing, or severe dizziness after leaving the clinic.

Good to know: Other heart problems, like abnormal heart rhythm, are also possible with IV ketamine. So let your healthcare provider know if you have any existing heart conditions.

6. Slowed breathing

Ketamine can slow your breathing — but this is rare. It’s more likely if you’re given ketamine for sedation or anesthesia or if you take other medications that slow breathing. Examples include:

• Benzodiazepines like alprazolam (Xanax)

• Opioids like hydrocodone

• Muscle relaxers like cyclobenzaprine

• Barbiturates like phenobarbital

• Alcohol

Give your healthcare provider and pharmacist an updated list of the medications you take. They may recommend avoiding certain medications if you receive ketamine. And your provider will monitor your vital signs to make sure you're breathing normally before you go home.

7. Suicidal thoughts and behaviors

Ketamine might help reduce any suicidal thoughts with your depression. But ketamine treatments don't work for everyone. And it’s possible to develop new thoughts of self-harm after starting treatment.

Stay in close contact with your healthcare provider or loved one being treated with ketamine. Be on the lookout for warning signs of suicidal ideation. And get help right away if you notice any of them.

Good to know: If your loved one is experiencing suicidal thoughts, find tips on how to talk to them about it in this video.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

8. Misuse

Ketamine is a controlled substance because it has a risk of dependence and misuse. In fact, ketamine misuse is increasing in the U.S.

It’s unlikely that ketamine treatments for depression given in medical settings will lead to misuse. But people with a past or present substance use disorder may be at greater risk.

Ketamine misuse may be more likely if it’s used at home. The FDA recently warned against home-use of ketamine pills or nasal sprays made by compounding pharmacies. Ketamine misuse can cause dangerous adverse effects, including trouble breathing and “ketamine bladder” — bladder inflammation that may lead to kidney damage.

If you or someone you know struggles with substance use, help is available. Call SAMHSA’s National Helpline at 1-800-662-4357 to learn about resources in your area.

When should you contact your healthcare provider about ketamine side effects?

Most ketamine side effects are short lived. But let your healthcare provider know if you notice any lingering symptoms after you get home from the clinic. 

Get medical help right away if you notice any of the following:

• Severe mood changes

• Disorientation, or altered sense of reality

• Trouble urinating

• Pink or red urine

• Chest pain

• Severe dizziness

• Trouble breathing

• Thoughts of self-harm

Why trust our experts?

Written by:

Daphne Berryhill, RPh

Daphne Berryhill, RPh, has two decades of experience as a clinical pharmacist. She spent most of her career in the Chicago area practicing in-home infusion.

Edited by:

Amy B. Gragnolati, PharmD, BCPS

Amy Gragnolati, PharmD, BCPS, is a pharmacy editor for GoodRx. Amy currently holds her pharmacist license in Georgia and California.

Reviewed by:

Nicole Rowe, MD

Dr. Nicole Rowe, MD, is a telehealth family practice physician. She received her medical degree from the University of North Carolina School of Medicine and completed her residency in family medicine at University of Colorado’s Swedish Medical Center.

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