# How Does Spravato Work? A Look Inside the Nasal Spray

> How does Spravato work? Esketamine blocks the NMDA receptor instead of raising serotonin, which is why relief can arrive within a day rather than in weeks.

URL: https://foundationmedicalgroup.org/how-does-spravato-work/
Published: 2026-09-05
Updated: 2026-09-05

Spravato works by blocking the NMDA receptor, a glutamate gate on brain cells, instead of raising serotonin the way traditional antidepressants do. That different route is why some patients feel relief within a day or two rather than after 6 weeks of waiting. The FDA label is candid that the full mechanism is still unknown.
Below we walk through what the medication does in your brain, how fast it acts, what happens in your body after a spray, and why the whole thing takes place in a clinic.
How Does Spravato Work in the Brain? Esketamine is the S-enantiomer of ketamine, meaning it’s one mirror-image half of the ketamine molecule. According to the prescribing information, it acts as a non-selective, non-competitive antagonist at the NMDA receptor, which is a type of glutamate receptor.
Glutamate is the brain’s main excitatory messenger. Roughly speaking, it’s the accelerator, while another chemical called GABA acts as the brake. Serotonin, dopamine, and norepinephrine, the targets of standard antidepressants, sit in a different signaling system altogether. Different system, different timeline. That’s the whole idea.
So what does blocking that gate accomplish? Honestly, the label doesn’t say. Its own sentence is blunt: “The mechanism by which esketamine exerts its antidepressant effect is unknown”. What researchers describe is a downstream burst of glutamate signaling that appears to strengthen connections between neurons, a process called synaptic plasticity.
The working idea in the field is that long depressive episodes weaken those connections, particularly in circuits tied to mood regulation. Esketamine seems to prompt repair rather than simply topping up a chemical. Or rather, that’s the model. The label says the mechanism is unknown, and we’d rather keep saying so than dress a theory up as a finding. That idea explains the speed better than a serotonin model does, though it remains a model rather than settled fact.
There’s a second reason the glutamate route matters for people who’ve cycled through pills. Standard antidepressants adjust the level of a messenger and then wait for the brain to adapt, which takes weeks. A drug that acts on connection strength directly doesn’t have to wait for that slow adaptation, at least in theory.
One practical footnote. Esketamine breaks down into a metabolite called noresketamine, which acts at the same receptor with weaker binding, so the effect fades as your body clears both.
How Is Spravato Different From Traditional Antidepressants? We compared the two side by side, because the difference is structural rather than cosmetic.
Feature Spravato (esketamine nasal spray) Standard antidepressants Main target NMDA receptor, part of the glutamate system Serotonin, norepinephrine, or dopamine reuptake How it’s given Nasal spray in a certified clinic Pill taken at home Typical timing of first change Reported as early as 24 hours in one trial Improvement builds over the first weeks Frequency Twice weekly, then weekly or every 2 weeks Once daily Supervision At least 2 hours after each dose None required Approved use Treatment resistant depression, alone or with an oral antidepressant First-line depression treatment That last row carries more weight than it looks. Spravato isn’t a starting point. It’s approved for treatment resistant depression, which means depression that hasn’t improved after adequate trials of other antidepressant medication.
Plenty of our patients arrive at the Richmond, VA clinic after their third or fourth pill and assume they’ve run out of road. They haven’t. A different mechanism is exactly what a stalled case may need, and it’s reasonable to compare treatments openly before you choose.
How Fast Does Spravato Work? Faster than a pill, but not instantly, and not for everyone.
In the monotherapy trial known as Study 3, esketamine at 56 mg and 84 mg beat placebo nasal spray on depression scores at day 2. That is about 24 hours after the first dose, and the separation held through day 28. In the two studies of adults with major depressive disorder and acute suicidal ideation, a treatment difference showed up at 4 hours.
But rapid relief on a rating scale isn’t the same as feeling well. Both groups in those suicidality studies kept improving through day 25, and the gap between them didn’t widen much over time. Spravato hasn’t been shown to prevent suicide, and the label says so directly.
Here’s how we frame it with patients. In our experience the question that comes up after session one is whether it worked, and a single session cannot answer that. The first session tells you how your body handles the medication. The 4-week induction phase tells you whether it’s helping. Your provider reviews progress at the end of induction and decides whether continuing makes sense, rather than letting a course drift on for months without a check.
What Happens in Your Body After a Spravato Dose? Each device delivers two sprays holding 28 mg of esketamine. A 56 mg dose uses two devices, an 84 mg dose uses three, with a 5-minute rest between each.
From there the pharmacology is quick:
About 48 percent of the dose reaches your bloodstream, which is high for a nasal medication. Blood levels peak 20 to 40 minutes after the last spray of the treatment session. Concentrations fall sharply for 2 to 4 hours, then taper with a half-life of 7 to 12 hours. Less than 1 percent leaves the body unchanged in urine, because the liver handles nearly all of it. So line those numbers up against the clinic clock. The schedule stops looking arbitrary. Blood pressure peaks near 40 minutes, which is when your team takes a reading. Cognitive testing in healthy volunteers showed a dip at 40 minutes that matched placebo again by 2 hours. Sleepiness matched placebo by 4 hours.
Absorption through the nose also explains a quirk patients notice. The sprays land on nasal tissue, so a stuffy nose, a recent cold, or a fresh dose of decongestant can all change how much medication crosses into the blood. Our team asks about this at check-in for a reason.
That’s also why the label tells you to skip food for 2 hours and liquids for 30 minutes before a spravato dose. It asks you to take any nasal steroid at least an hour ahead, so it doesn’t interfere with absorption.
Why Does Spravato Need Medical Supervision? Because the same pharmacology that acts fast also produces sedation and dissociation fast. Around 48 to 61 percent of patients showed measurable sedation in trials, and dissociation ran from 61 to 84 percent depending on dose and study group.
Under the Spravato REMS program, the clinic must be certified, the pharmacy must be certified, and you use the spray yourself while a provider watches. Monitoring runs for a 2 hour stretch at minimum, with pulse oximetry on your finger, and you leave when your team judges you steady rather than when a timer goes off.
The monitoring window is the part patients tell us they worry about most, and the worry is usually about the ride home rather than the medication. Two rules follow you home. Which is inconvenient, and not negotiable. Don’t drive or use heavy machinery until the next day after a full night of sleep, and arrange your ride in advance. Common side effects such as dizziness and nausea usually fade before discharge, though the driving rule stands regardless of how well you feel.
How Does the Dosing Schedule Work? For treatment resistant depression, the label sets induction at twice per week for weeks 1 to 4, at either 56 mg or 84 mg. Weeks 5 to 8 move to once weekly. From week 9, the maintenance phase runs weekly or every 2 weeks, with the aim of finding the least frequent dosing that holds your response.
One practical note on access. Spravato has to be given in a certified clinic, so at Foundation Medical Group it runs from the Richmond, VA office. Our Dallas, Texas, Decatur, Georgia, and American Fork, Utah clinics handle psychiatry and medication management instead. Spravato therapy sits inside a broader plan rather than standing alone. Most patients keep an oral antidepressant, keep therapy going, and keep their existing medication management appointments. If esketamine treatment isn’t the right fit, TMS therapy offers another route, since transcranial magnetic stimulation uses magnetic pulses instead of a drug.
More Questions About How Spravato Works Does Spravato cure depression? No. It treats symptoms while you take it, the same way most mental health treatment does. Many patients stay on it for months, and 479 patients in the phase 3 program received at least 6 months of treatment.
Is a ketamine infusion the same thing? Not quite. IV ketamine therapy for depression is off-label, and dose, setting, and monitoring vary between providers. Spravato follows one label, one REMS program, and one monitoring standard.
Can I keep taking my other medication? Usually yes, and often you should. The label covers Spravato used with an oral antidepressant as well as on its own. Your provider will flag a few interactions worth watching: benzodiazepines, opioids, and alcohol increase sedation, while stimulants and MAOIs push blood pressure higher.
What if I feel nothing after the first dose? That’s common and it isn’t a verdict. Judge the treatment option at the end of the 4-week induction phase, with your provider looking at your rating scale scores rather than at memory alone.
Key Takeaways Spravato contains esketamine, which blocks the NMDA receptor rather than boosting serotonin. The FDA label states the exact antidepressant mechanism is still unknown. Researchers link the effect to glutamate signaling and synaptic plasticity. One trial showed separation from placebo at day 2, and suicidality studies showed a difference at 4 hours. About 48 percent of the dose is absorbed, peaking 20 to 40 minutes after the last spray. The half-life runs 7 to 12 hours, so the drug clears the same day. Sedation and dissociation are why the Spravato REMS requires 2 hours of observation. Induction is twice weekly for 4 weeks, then weekly, then weekly or every 2 weeks. It’s approved for treatment resistant depression, not as a first depression treatment. Start With an Evaluation in Richmond Understanding the mechanism is useful, but the decision comes down to your history. Our physician-led team at Foundation Medical Group in Richmond, Virginia reviews the antidepressants you’ve tried, your blood pressure, and your other health conditions before recommending anything.
Read more about Spravato for depression, the side effects to expect, and what Spravato costs. When you want a straight answer about fit, our Richmond Spravato team is ready to talk.
Sources Spravato (esketamine) prescribing information, DailyMed. FDA approval label for Spravato, 2019. Ketamine, StatPearls, NCBI Bookshelf. National Institute of Mental Health, Depression.