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How Long Do the Positive Effects of Ketamine Therapy Last?

Ketamine therapy offers a significant advantage in treating disorders that include depression, anxiety, PTSD, chronic pain, and addiction due to its rapid and highly effective nature. In the case of depression, a response rate of 70% or greater can be anticipated. The positive effects of ketamine commence within hours and reach their peak at approximately 24 hours. This contrasts with conventional antidepressants such as selective serotonin reuptake inhibitors (SSRIs) like Prozac and Lexapro, which may necessitate over six weeks to manifest an impact with response rates oftentimes as low as 30-40%.

Research indicates that the favorable outcomes of a single ketamine infusion can endure for up to a week, relying solely on medication. However, the integration of psychotherapy and adaptive behaviors has been proven to extend the duration of these effects. For more updated insights into the duration of ketamine's effects and the extension of its effects through adaptive behaviors, consider referring to Part two titled 'How Long Do the Effects of Ketamine Last? Extending The Duration Through Adaptive Behaviors'.

Given that the standard treatment approach for ketamine infusion therapy encompasses a series of six infusions spread across 2-6 weeks, an important query arises: what is the lasting duration of the positive effects of ketamine following this established practice? By examining the scientific literature, we can address this vital question that holds significance for both clinicians and patients.

What can you expect in the short-term from ketamine therapy?

As previously discussed, ketamine therapy may include four routes of administration including intravenous, intramuscular, oral, or nasal. At Innerbloom Ketamine Therapy, we primarily choose intravenous ketamine for reasons including safety, efficacy, and ease of use in a monitored setting. The effects of ketamine are felt within minutes of an intravenous infusion, peak at about 20 minutes, and last for about 45 minutes per our infusion protocol. The residual effects of ketamine last 1-3 hours after an infusion. With the half-life being approximately 3 hours, ketamine is completely out of the system within the same day of the administration.

How long do the positive effects of ketamine last?

In a 2019 study examining the duration of the antidepressant effects of ketamine therapy, they found that, “ketamine has a robust and rapid effect on depression, which was seen immediately after administration of ketamine and sustained at the end of 1 month.” This includes the use of IV ketamine starting at 0.5 mg/kg over 40 minutes using an infusion pump which is like our protocol at Innerbloom Ketamine Therapy.

Studies suggest that IV ketamine is the superior route of administration

It is important to note that oral forms of ketamine have not been shown to have similar rapid acting or long-lasting effects that is seen in intravenous ketamine. A comprehensive systematic review and meta-analysis noted that the antidepressant effects of oral ketamine seemed to occur in a delayed fashion at the 2nd week of treatment.

Additionally, they stated, “Our meta-analysis for primary outcomes (response rate and remission) do not provide substantial evidence for a strong recommendation for oral ketamine, underscoring caution when considering oral ketamine for depression.”

While we strongly feel further studies and evidence is needed for the proper use of oral ketamine, there could be a potential role for oral ketamine as an option in a maintenance phase after a proven positive response from an IV ketamine series of infusions.

A brief discussion about Esketamine (SPRAVATO®)

Ketamine is available in two forms: Esketamine and racemic ketamine used in an IV ketamine infusion. Esketamine is administered via a nasal spray at a dose of 56mg or 84mg. IV ketamine, on the other hand, is weight based and is titrated up to find the optimal “goldilocks” dose with the peak positive effects. A 2020 study comparing the efficacy of racemic ketamine to Esketamine for depression concluded that IV ketamine appeared to be more efficacious than intranasal ketamine and stated, “racemic ketamine demonstrated more overall response and remission rates, as well as lower dropouts due to adverse events.”

At Innerbloom Ketamine Therapy, the two things we feel are most important when using this medicine are efficacy and safety. With that in mind, we choose IV ketamine as we believe it is the superior form of ketamine given the ability to titrate and find the most efficacious dose for each individual. The added benefit of IV ketamine is the ability to stop or pause an infusion, which simply is not possible with other routes of administration including intramuscular, oral, or nasal.

Will I need “booster” infusions after the 6-infusion series?

In a recent episode from the Tim Ferris Show, Dr. John Krystal points out that the majority of patients follow a protocol of 6 to 8 infusions to achieve remission of their symptoms. After this series of infusions, some individuals are completely done with ketamine therapy, while others may find it beneficial to transition into a maintenance phase where they return for additional infusions on an as-needed basis which may include infusions as frequent as every 3-4 weeks, while others are able to extend the time in between boosters. It is our opinion that potentially needing booster infusions periodically throughout the year is better than the alternative which may include being on a daily toxic antidepressant with significant side effects and potentially limited relief of symptoms.

What can someone do to extend the positive effect of ketamine?

Again Dr. John Krystal said it best, “ketamine is an intervention embedded in an overall treatment.” We agree with this statement and strongly feel that ketamine is simply one piece of the puzzle to the overall healing process. Attention to preparation and aftercare which includes integration and potentially psychotherapy may be helpful in extended the beneficial effects of ketamine therapy.

At Innerbloom Ketamine Therapy, we feel the ideal scenario is to start preparation with a trained therapist prior to the first infusion and continue physiotherapy between IV ketamine treatment sessions. The bottom line is that ketamine is not a magic pill and to ensure long-term success, preparation and aftercare should not be ignored. Additionally, we can’t stress enough the importance of attention to overall wellbeing of each patient including other vital aspects of health such as proper sleep, nutrition, social support, and stress reducing practices


Ketamine therapy is a highly effective and attractive treatment option for mood disorders such as treatment-resistant depression, although the route of administration and detail to the overall care of the patient before and after ketamine treatment plays a pivotal role in optimizing the durability of the positive effects. The long-lasting effects of ketamine and healing takes proper planning and work. At Innerbloom Ketamine Therapy we strive to optimize your overall health to ensure that you get the most out of this safe, effective, and potentially life-changing medicine.

Tags: anxiety, best ketamine clinic, depression, esketamine, fibromyalgia, generalized anxiety disorder, iv ketamine, ketamine, ketamine assisted psychotherapy, mental health, psychedelics, PTSD, san luis obispo, suicide

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