How Long Does Ketamine Nasal Spray Last? Immediate, Short Term, Long Term

Ketamine nasal spray can produce both immediate and longer-lasting effects. How long it lasts depends on the formulation (esketamine vs. ketamine) and how it’s used. In clinical care, “ketamine nasal spray” most often refers to Spravato® (esketamine), the only FDA-approved intranasal formulation. Esketamine is not a ketamine analog; it is one of the two mirror-image halves of ketamine itself, and it is why the S-form is delivered as a spray.

Spravato nasal spray’s effects generally unfold across three phases: immediate in-session effects, short-term antidepressant relief, and longer-term mood improvement. Understanding what happens at each stage can help you set realistic expectations and decide whether nasal spray treatment fits into your overall depression care plan.

How long does ketamine nasal spray last?

​​Ketamine nasal spray has short-lived physiological effects and longer-lasting mood benefits. The immediate sensations from Spravato occur during the in-clinic session and typically resolve within a couple of hours. The antidepressant benefits often begin within 24 hours and continue to build over time with repeated treatments, with more sustained improvement developing over several weeks.

Immediate effects (40–120 minutes)

Spravato begins working quickly. Most patients notice that the dissociative effects peak within 30 to 40 minutes of dosing and typically resolve by two hours after administration. These early effects reflect the body’s immediate response to the medication’s neural mechanisms.

These immediate nasal spray effects may include:

• dissociation or feeling detached from thoughts or surroundings
• altered sensory perception (sounds, visuals, time distortion)
• deep relaxation or light euphoria
• temporary dizziness or nausea
• a short-lived increase in blood pressure.

Short-term effects (24 hours)

After the acute dissociation subsides, ketamine nasal spray typically produces antidepressant effects within 24 hours, with continued improvement through the structured eight-week protocol. This rapid onset distinguishes ketamine nasal spray from traditional antidepressants, which often take weeks to work.

Many esketamine patients report:

• improved mood
• reduced depression symptoms (source)
• decreased suicidal thinking
• greater mental clarity.

Long-term effects (weeks to months, or years)

Ketamine nasal spray can support lasting depression relief over weeks, months, or years when patients continue treatment as prescribed. Repeated dosing helps stabilize the early benefits that appear after initial sessions, and maintenance dosing (following the protocol’s completion) on a weekly or biweekly basis can prevent symptoms from returning in the long term. 

An extensive, multi-year clinical follow-up study of people with treatment-resistant depression found that many Spravato nasal spray patients maintained improvement for an average of about three years. Some continued treatment and experienced benefits for more than four years.

Research suggests that sustained esketamine treatment can lead to:

• steadier mood regulation
• fewer depressive relapses
• longer symptom-free intervals
• improved response when combined with an oral antidepressant.

How nasal spray formulation impacts results

The nasal spray formulation (Spravato vs. generic compounded ketamine) plays a significant role in determining the consistency and duration of intranasal ketamine benefits.

Spravato vs compounded ketamine nasal spray

Spravato contains esketamine (S-ketamine), which is one specific half of the ketamine molecule that has been isolated and studied for depression. Certified mental health clinics administer Spravato under standardized dosing and monitoring protocols, and long-term clinical data support its durability of benefit for patients with treatment-resistant depression.

Compounded ketamine nasal spray typically contains racemic ketamine (a mixture of S-ketamine and R-ketamine) and is prescribed off-label, often for use outside of clinics. This approach introduces greater variability in dosing and absorption, and limited long-term data make it harder to predict sustained results.  Additionally, the Food and Drug Administration has issued formal warnings regarding compounded ketamine nasal sprays due to inconsistencies in dosing and a lack of clinical monitoring.

How long does ketamine nasal spray last for pain?

Spravato is not FDA-approved for chronic or acute pain conditions, and it is not used for pain management. Compounded nasal sprays are also rarely appropriate for pain due to safety and variability issues.

Ketamine-based pain treatment typically involves IV infusions at higher doses and longer durations, sometimes delivered over three to ten consecutive days. These protocols work on different mechanisms and timelines than ketamine nasal spray treatments for depression.

For those curious about ketamine’s role in pain relief, IV therapy is the evidence-based option.

How long does the spray stay in your system?

Esketamine nasal spray has a relatively short half-life of 7-12 hours, meaning it largely clears the body within 2-3 days. However, this timeline does not reflect the duration of its antidepressant effects.

Ketamine’s benefits often last longer than the medication itself because the brain continues responding after the drug clears. The treatment appears to support healthier communication between brain cells and boost proteins involved in learning and adaptation, which helps explain why symptom relief can persist for days, weeks, months, or years after treatment.

What does ketamine nasal spray work best for?

Ketamine nasal spray (Spravato) is FDA-approved for treatment-resistant depression and for suicidality in major depressive disorder. Treatment is most effective for patients with these conditions. 

Relief for treatment-resistant depression (TRD)

Randomized clinical trials showed that esketamine nasal spray can produce rapid and superior reductions in depressive symptoms compared to placebo in people who have not responded adequately to at least two prior antidepressants. 

Researchers believe this effectiveness comes from esketamine’s action on the brain’s glutamate system, which is distinct from traditional serotonin-based antidepressants. 

Relief for suicidal ideation in major depressive disorder

Clinical data from the FDA also demonstrates meaningful symptom relief in adults with major depressive disorder (MDD) with suicidal thoughts. Esketamine’s rapid antidepressant effects increase synaptic connectivity in brain regions involved in emotion and decision-making. This shift in neural signaling can reduce the intensity of depressive symptoms and suicidal thoughts during acute crises.

What is the best nasal spray protocol for depression?

The Spravato protocol for depression follows a standardized dosing schedule:

• Weeks 1-4: Supervised doses twice weekly.
• Weeks 5-8: Supervised doses once weekly.
• Maintenance phase: Supervised doses weekly or every other week, based on the individual’s response. This phase can last for years in some cases. 

This structured approach is designed to maximize long-term benefits while minimizing risks, such as respiratory depression, abuse, or misuse.

How can I make Spravato last longer?

Spravato tends to produce more durable symptom relief when used consistently according to protocol, and supported by psychotherapy, integration coaching, stable routines, and appropriate medication management. 

Following the full induction and maintenance protocol

The Spravato protocol occurs in phases because antidepressant benefit builds cumulatively over time, not just from individual doses. Clinical trials have shown that patients who complete both the induction phase and ongoing maintenance are more likely to sustain symptom improvement than those who discontinue treatment once early relief appears.

Keeping sessions consistent

Consistency refers to how reliably patients follow the prescribed schedule within each phase. Studies indicate that extending the interval between doses too quickly, particularly during transitions between induction and maintenance, can allow depressive symptoms to return. In contrast, consistent administration supports sustained benefit over time.

Pairing treatment with psychotherapy or coaching

Ketamine appears to temporarily increase cognitive flexibility and emotional openness, creating a window after treatment during which psychotherapy or integration coaching may be especially effective. Combining Spravato with talk therapy in this window can help patients process emotions, develop coping strategies, and translate symptom relief into lasting behavioral change.

Maintaining sleep, nutrition, and de-stress routines

Spravato’s antidepressant effects can last longer when patients support their holistic health between treatments. Practical steps include keeping a consistent sleep and wake time, prioritizing 7-9 hours of sleep, eating regular meals with adequate protein and hydration, and limiting alcohol or late-day caffeine, which can disrupt mood and sleep quality. These actions can help protect the gains made during treatment and reduce the likelihood of symptom rebound.

Review medications that may blunt ketamine’s effects

Patients may be able to extend and strengthen Spravato’s antidepressant benefits by reviewing current medications with their provider to identify any that could interfere with its effectiveness. Some medications, including certain benzodiazepines, may reduce ketamine’s antidepressant efficacy. A thorough medication review enables clinicians to strike a balance between safety and symptom management, while optimizing the nasal spray’s impact.