We are frequently asked about possible side effects of Ketamine during our pre- treatment consultations at Palomar KLN. I thought it would be helpful to write a short blog about it. The benefits of low dose ketamine outweigh the risk most of the time. However, there are no medications out there that are side effect free.

The vast majority of our patients in the clinic tolerate the treatment well. Most describe the treatment as a “floating” or “out of body” experience. This effect usually resolves after 20-30 minutes.

Here are a few other effects that may be experienced with low dose ketamine infusion.


Probably the most common but treatable side effect we see is nausea. This is often described as a vertigo or motion sickness feeling. If nausea does occur, it typically resolves fairly quickly after treatment. At Palomar KLN, we have been very successful at preventing nausea by treating with medications prior to the infusion. Some effective medications we commonly use include Meclizine, Zofran, and scopolamine patches.

Hemodynamic Changes

We do see small increases in blood pressure and sometimes heart rate. These findings are usually mild or marginal changes that also resolve quickly after the infusion has ended. At Palomar KLN we conduct a thorough pre infusion health history and closely monitor blood pressure and heart rate during the infusion for your safety. It’s important to provide us with a complete health history and list of medications prior to the infusion.

Cognitive Effects

We know that low dose ketamine therapy produces rapid relief of suicidal ideation and treatment resistant depression. This outcome is supported by decades of research. However, a common question we are asked is “does this treatment cause problems with memory and cognition”?

Let’s discuss the short term side effects first. We do know that ketamine can induce a decline in attention, executive function, and memory on the day of treatment (Davis et al., 2021). These effects typically resolve within 24hrs (Davis et al., 2021). The study by Davis was limited to data collected about the short term use of ketamine on the day of treatment.

Alternatively, another short term study shows that ketamine used in the post operative setting had positive findings. This study showed that ketamine may actually reduce the effects of post operative cognitive dysfunction (Hovaguimian et al., 2018). This may seem conflicting and it actually is. This could be related to different dosing and durations used.

It is important to point out that we are talking about effects of sub-anesthetic/low doses of ketamine. This dosing is what we give in our infusion clinic. Certainly, large doses used with abuse of the drug may have vastly different cognitive effects.

So what are the long term cognitive effects? There are several studies out there and I’ll give reference to one of the most relevant ones. A study by Souza- Marques looked at several different articles and reviewed the short term and long term effects of ketamine. Five of the studies reported improvements in processing speed, verbal memory, visual memory, working memory, or cognitive flexibility (Souza-Marques et al, 2021). Additionally, Souza-Marques stated that the results suggest neuropsychological functions and brain areas commonly impaired in treatment-resistant depression may especially benefit from sub-anesthetic/low dose ketamine infusions.

What about Alternative Therapies?

I also want to take a moment to compare an alternative therapy which is ECT treatment. ECT stands for electro-convulsive therapy and usually requires patients to be given a short general anesthetic followed by the stimulus to induce a seizure. This has been around for a very long time and does have positive effects in treating depression. ECT is effective but does have significant and often times lasting affects on cognition and memory.

Ketamine, on the other hand, has an improved side effect profile. There’s no general anesthetic needed, there’s no seizure, and cognitive effects are improved. An article in the Journal of Psychiatric Research actually shows that both treatments work but ketamine works faster with improved neurocognitive function (Basso et al., 2020).

That means there may actually be improvements in cognition and ketamine may actually be beneficial. I can’t speak for everyone but that sounds better than a forced seizure.

In conclusion, I just want to say that at Palomar KLN we believe in Ketamine treatment. We have seen the positive effects for treating depression and pain management. At Palomar KLN, we have the education, experience and expertise to safely give you the latest and greatest for good health. Additionally, we welcome any opportunity to answer questions and to help you on your journey in pursuit of wellness!


Basso, L., Bonke, L., Aust, S., Gartner, M., Heuser-Collier, I., Otte, C., Wingenfield, K., Bajbouj, M. & Grimm, S. (2020). Antidepressant and Neurocognitive Effects of Serial Ketamine Administration versus ECT in Depressed Patients. Journal of Psychiatric Research, 123, 1-8. https://doi.org/10.1016/j.jpsychires.2020.01.002

Davis, M. T., DellaGiogia, N., Maruff, P., Pietrzak, R. H. & Esterlis, I. (2021). Acute Cognitive Effects of Single-Dose Intravenous Ketamine in Major Depressive and Posttraumatic Stress Disorder. Translational Psychiatry, 11(1), 1-10. https://doi.org/10.1038/s41398-021-01327-5

Hovaguimian, F., Tschopp, C., Beck-Schimmer, B. & Puhan, M. (2018). Intraoperative Ketamine Administration to Prevent Delirium or Postoperative Cognitive Dysfunction: A Systematic Review and Meta-Analysis. Acta Anaesthesiologica Scandinavica, 62(9), 1182-1193. https://doi.org/10.1111/aas.13168

Souza-Marques, B., Santos-Lima, C., Araujo-de-Freitas, L., Vieira, F., Jesus-Nunes, A. P., Quarantini, L. C. & Sampaio, A. (2021). Neurocognitive Effects of Ketamine and Esketamine for Treatment-Resistant Major Depressive Disorder: A Systematic Review. Harvard Review of Psychiatry, 29(5), 340-350. https://doi.org/10.1097/hrp.0000000000000312

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