Most of what patients read about IV ketamine therapy focuses on the science of how it works or the dramatic speed at which it can act — but very little prepares them for what the weeks of treatment actually feel like, how the dosing process unfolds, or what maintenance looks like once the initial series ends. At the Houston Center for Advanced Psychiatric Treatment, we have personally administered over 9,000 treatments with ketamine or esketamine, and that experience has taught us that patients who understand the full arc of treatment before they start are better positioned to get the most from it. Results vary by individual, and what follows is an honest account of what the IV ketamine treatment timeline typically looks like at our practice — not a guarantee of any particular outcome.
Why the Timeline Matters
Ketamine works differently than standard antidepressants. Where SSRIs (selective serotonin reuptake inhibitors) and SNRIs (serotonin-norepinephrine reuptake inhibitors) typically require four to six weeks of daily dosing before producing meaningful effect, IV ketamine can produce antidepressant changes within hours. The National Institute of Mental Health has highlighted this rapid-acting property as one of ketamine’s most clinically significant characteristics — particularly for patients with treatment-resistant depression who have waited through multiple medication trials without relief.
That speed is real. But it can also create unrealistic expectations about what a single infusion produces, how stable the effects are, and how long they last without continued care. Understanding the distinction between the initial response, the full treatment course, and maintenance helps patients make better decisions and set more realistic markers for what progress looks like.
Before the First Infusion
The timeline begins before any IV is placed. At our practice, every patient starts with a consultation in which we review psychiatric and medical history, current medications, prior treatment trials, and factors that could affect candidacy or safety. Certain conditions — uncontrolled blood pressure, unstable heart disease, untreated thyroid disease, active substance use, current manic phase of bipolar disorder, or active psychotic symptoms — are contraindications that we screen for carefully.
This step is not a formality. Ketamine produces real neurobiological effects, and the dosing needs to be tailored to the individual to maximize both safety and response. We do not run a standardized protocol — we adjust concentration, infusion duration, and pre-medications based on each patient’s history and how they respond in real time. That customization is one of the reasons our personal response rate at this practice is over 80%.
The First One or Two Infusions: Assessment
The first infusion is as much diagnostic as it is therapeutic. Most patients will know within one or two infusions whether ketamine is likely to help them. That is a meaningful characteristic: rather than waiting weeks to assess medication response, patients and providers have early, actionable information.
During the infusion itself, patients receive ketamine intravenously over approximately 40 minutes in a private room with full heart and vital signs monitoring. Dr. Prashad remains present throughout, adjusting dosing in real time based on tolerance and response. Most patients remain awake and report a relaxing, somewhat dissociative experience — changes in perception, a sense of lightness or disconnection, slower thoughts. These effects resolve after the infusion ends. Side effects between treatments are typically absent, and the total office visit runs approximately 90 minutes. A trusted driver is required.
The National Institutes of Health has confirmed that side effects from a single antidepressant dose of IV ketamine are mild and brief, supporting the safety profile of this approach in clinical settings.
Infusions 3 Through 6: The Full Course
If the first one or two infusions produce a positive response, the recommended course is six total infusions completed within the first two weeks. This compressed timeline is intentional. Research on repeated ketamine sessions demonstrates that multiple infusions produce cumulative antidepressant benefits and extend remission periods beyond what a single infusion achieves (PMC: Repeated Ketamine Sessions). The structured series establishes the neurobiological foundation that maintenance treatment then builds on.
Not every patient will respond equally across the six infusions. Some patients experience a sustained lift beginning with the second or third infusion; others report that the effect accumulates gradually across the full course. We monitor response closely throughout and adjust dosing accordingly. What we do not do is assume that one patient’s arc will match another’s — because it rarely does.
After the Initial Series: Maintenance
This is the part of the ketamine timeline that catches many patients off guard. The initial series of six infusions is not the endpoint — it is the foundation. For most patients, the antidepressant effects of the initial series last somewhere between several weeks and several months, with individual variation being significant. Research published in the American Journal of Psychiatry supports both single and repeated ketamine infusion approaches, and shows that maintenance infusions extend the duration of benefit for patients who respond to the initial course (American Journal of Psychiatry).
At our practice, maintenance infusions are typically scheduled three to five weeks after completing the initial series of six — timed to when effects begin to wear off rather than on a fixed calendar. A single booster infusion at that point can often restore the response established during the initial course. Over time, many patients find that the interval between maintenance infusions lengthens as stability increases, though this is highly individual.
Patients with long-standing chronic depression may require more consistent maintenance than patients for whom this episode is more recent. We discuss the likely maintenance picture during consultation so patients can plan realistically.
Two Practical Barriers: Cost and Continuity
Cost. IV ketamine is not covered by insurance, as it remains an off-label use of the medication. At our practice, each infusion is $650. When a full series of six is completed, the sixth infusion is provided at a 50% discount. We require payment at the time of treatment and accept cash or credit cards — not checks. Financing is available for patients who qualify. We know that cost is a real factor in whether people can access care, and we are transparent about it before any treatment begins.
Continuity. Patients sometimes complete the initial series and then discontinue follow-up, either because they feel better and assume the work is done, or because scheduling maintenance feels difficult. Both responses are understandable, and we want to be direct: maintenance is part of the treatment, not optional aftercare. Research suggests that sustaining ketamine’s antidepressant effects requires a continued maintenance regimen for many patients. Discussing the full arc before you begin — not just the first two weeks — is something we prioritize in every initial consultation.
For patients interested in extending and deepening the effects of IV ketamine, we also offer the ONE-D TMS: Ketamine + Deep TMS combination protocol and Ketamine-Assisted Psychotherapy (KAP), in which the neuroplasticity window opened by ketamine is used actively in a therapeutic context. These are options we discuss with patients based on their history and goals.
Frequently Asked Questions
How quickly will I feel something during an infusion? Most patients notice perceptual and cognitive changes during the infusion itself — within the first 10 to 20 minutes of administration. These include changes in vision, a sense of lightness or disconnection, and slower thoughts. They resolve after the infusion ends. Antidepressant changes — shifts in mood, energy, and the quality of depressive symptoms — are distinct from the infusion experience itself and may be noticed in the hours or days following treatment.
What if I don’t respond to the first two infusions? Approximately 70 to 80% of patients respond to the IV ketamine series at our practice. For patients who do not show a positive early response, we discuss whether completing the full series is appropriate or whether a different approach — such as SPRAVATO® treatment, Deep TMS, or the Ketamine + Deep TMS combination — may be a better fit. We do not recommend continuing a treatment that is not working.
Can I continue my current medications during IV ketamine treatment? Very few medications cannot be combined with ketamine. Dr. Prashad reviews your full medication regimen during consultation and addresses any adjustments that may be needed. For patients receiving IV ketamine who do not currently have a psychiatrist, Dr. Prashad will also prescribe and manage psychiatric medications as part of your care.
How long does each maintenance infusion last compared to the initial series? Maintenance infusions follow the same basic protocol as the initial series — approximately 40 minutes of IV administration in a private room, with the same monitoring and the same total visit time of roughly 90 minutes. The dosing may be adjusted based on your response history. Many patients find that a single maintenance infusion restores the response they established during the initial six.
Is the ketamine experience the same every time? Not necessarily. The perceptual experience during infusion can vary across sessions, and some patients describe it as more or less intense at different points in the course. What matters clinically is the antidepressant response — which we track systematically — not the quality of any individual infusion experience. Dr. Prashad adjusts dosing and pre-medications based on that data.
Key Takeaways
- The IV ketamine timeline has three distinct phases: an initial one-to-two infusion assessment period, a full series of six infusions over two weeks, and an ongoing maintenance phase with boosters scheduled as effects begin to wear off.
- Response is typically detectable within the first one or two infusions — a meaningful advantage over oral antidepressants that require weeks of daily dosing before assessment is possible.
- Repeated infusions produce cumulative benefit; the initial series establishes a foundation that maintenance treatment extends.
- IV ketamine is not covered by insurance; each infusion is $650, with the sixth at 50% discount when the full series is completed. Financing is available for patients who qualify.
- Results vary significantly by individual — maintenance schedules, response duration, and the need for combination approaches all depend on factors we assess throughout care.
The ketamine therapy timeline is not a short story — it is a process with distinct phases, and understanding each one before you begin is part of what makes it work. If you have questions about whether IV ketamine is appropriate for your history, or about what the full arc of treatment would look like for you specifically, call us at 832-436-4055 or schedule a consultation online. We will walk through the timeline honestly and help you decide whether this is the right next step.
References
Repeated Ketamine Sessions. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC6236511/
Single, Repeated, and Maintenance Ketamine Infusions. American Journal of Psychiatry. https://psychiatryonline.org/doi/10.1176/appi.ajp.2018.18070834
Side Effects of IV Ketamine. National Institutes of Health. https://www.nih.gov/news-events/news-releases/side-effects-mild-brief-single-antidepressant-dose-intravenous-ketamine
Medical Disclaimer
The information in this blog is for educational purposes only and does not constitute medical advice. IV ketamine therapy should only be pursued under the supervision of a licensed psychiatric provider who is familiar with your full medical and psychiatric history. Individual results vary. If you are experiencing a mental health crisis or thoughts of self-harm, please call or text 988 to reach the Suicide and Crisis Lifeline or go to your nearest emergency room.