Ketamine and SSRIs: What the Spravato Label and Studies Show

The official Food and Drug Administration (FDA) approved prescribing information for Spravato indicates the drug for treatment-resistant depression (TRD) either as monotherapy or in conjunction with an oral antidepressant. In Study 1, described in the Spravato label, all patients started a new oral antidepressant, an SSRI in 32 percent and an SNRI in 68 percent. The official prescribing information's drug interactions section lists central nervous system (CNS) depressants, psychostimulants, and monoamine oxidase inhibitors (MAOIs), but it contains no mention of serotonin and does not say whether combining it with an SSRI is safe or unsafe. We did not find a study that isolates concurrent SSRI use as a factor in the response to ketamine or esketamine. Our search was not exhaustive. We found no source on racemic ketamine taken with an SSRI, and none that settles serotonin syndrome risk for outpatient use. Your prescriber decides whether to combine them.

Evidence below is current to October 27, 2026. Decisions about starting ketamine, continuing an oral antidepressant, or changing one belong to your licensed prescriber.

Esketamine and Ketamine Evidence Across Concurrent Antidepressants

Clinical Parameter	Spravato (Esketamine Nasal Spray)	Racemic Ketamine (Intravenous or Other Routes)
FDA Approved Indications	Indicated for treatment-resistant depression in adults as monotherapy or in conjunction with an oral antidepressant, and for depressive symptoms in adults with major depressive disorder with acute suicidal ideation or behavior in conjunction with an oral antidepressant.	Studied as an add-on to ongoing antidepressant treatment in the research cited below. This page does not cover racemic ketamine's regulatory status.
Clinical Trial Context	In the label's Study 1, all patients started a new oral antidepressant: an SSRI in 32 percent (escitalopram or sertraline) and an SNRI in 68 percent (duloxetine or extended-release venlafaxine).	No trial data on racemic ketamine with an SSRI found in the sources reviewed. Smaller ketamine studies are covered in the benzodiazepine row and below.
Label Interaction Warnings	Section 7 lists CNS depressants (increased sedation), psychostimulants (increased blood pressure), and MAOIs (increased blood pressure). It makes no mention of SSRIs or serotonin.	This page does not cover racemic ketamine labeling.
Observed Interaction with Benzodiazepines	Mixed: a pooled post-hoc analysis of 451 patients found no meaningful 24-hour effect (more sedation); a retrospective study of 178 patients on subcutaneous esketamine linked benzodiazepine use to higher MADRS scores.	Andrashko et al. 2020: worse outcome at days 3 and 7 with higher doses; Feeney et al. 2022: less improvement at day 1 only; Frye 2015 is a letter with a title stating the same conclusion.
Serotonin Syndrome Evidence	The label does not mention serotonin syndrome; no source we reviewed settles outpatient risk.	A 2024 case report (one patient, recurrent serotonin syndrome after ketamine given for ECT) with a literature review that found one earlier case; the authors advise recognizing ketamine as a potential risk factor. This was an ECT setting, not outpatient esketamine.
Treatment Setting and Delivery	Delivered as a nasal spray in a healthcare provider's office, clinic, or hospital.	Studied in research and clinical settings, including intravenous administration.

What the Spravato Label Says About Oral Antidepressants

The official United States prescribing information for Spravato establishes that esketamine nasal spray is intended to be used either alone or alongside oral antidepressants. In the Spravato label on DailyMed (version 21, published September 24, 2026), the FDA-approved indications explicitly specify Spravato for treatment-resistant depression in adults as monotherapy or in conjunction with an oral antidepressant. A second approved indication, targeting depressive symptoms in adults with major depressive disorder (MDD) who have acute suicidal ideation or behavior, directs the medication to be administered in conjunction with an oral antidepressant.

The drug interactions segment within Section 7 of the Spravato label names three specific classes of pharmaceutical agents. Section 7.1 notes that concomitant use with CNS depressants, such as benzodiazepines, opioids, or alcohol, may increase sedation, requiring close clinical monitoring. Section 7.2 states that concomitant use with psychostimulants, including amphetamines, methylphenidate, modafinil, and armodafinil, may elevate blood pressure. Section 7.3 directs close blood pressure monitoring when Spravato is administered alongside monoamine oxidase inhibitors. The label instructs patients that their healthcare provider can evaluate whether it is safe to combine Spravato with other ongoing prescriptions.

The word serotonin does not appear anywhere in the Spravato label, and section 7 does not name SSRIs. We found no source that shows an SSRI changes the effect of ketamine or esketamine, and none that settles serotonin syndrome risk for outpatient use. Whether to combine them is your prescriber's decision. The label does not say the combination is safe or unsafe; its patient information says your provider can tell you whether it is safe to take Spravato with your other medicines. See our ketamine guide and the Spravato vs ketamine comparison.

Clinical Trials Combining Esketamine with SSRIs and SNRIs

In the label's Study 1 and in TRANSFORM-1, TRANSFORM-2 and SUSTAIN-1, esketamine nasal spray was given with an oral antidepressant. According to Section 14.1 of the Spravato label, Study 1 (clinical trial NCT02418585) evaluated adult patients aged 18 to <65 with treatment-resistant depression over a four-week period. After discontinuing prior antidepressant treatments, patients in Study 1 were randomized and all received a newly initiated daily oral antidepressant, consisting of duloxetine, escitalopram, sertraline, or extended-release venlafaxine. The newly initiated oral antidepressant was an SSRI in 32 percent of patients and an SNRI in 68 percent. Patients had discontinued their prior antidepressants before starting it, so Study 1 does not describe adding esketamine to a stable existing SSRI.

In the TRANSFORM-2 study published in the American Journal of Psychiatry, Popova et al. (2019) randomized adults with treatment-resistant depression and nonresponse to at least two antidepressants to esketamine nasal spray (56 or 84 mg twice weekly) plus a newly initiated antidepressant or antidepressant plus placebo nasal spray, finding that the change in MADRS score from baseline to day 28 was significantly greater with esketamine plus antidepressant than with antidepressant plus placebo (difference of least square means -4.0, 95% CI -7.31 to -0.64). In the TRANSFORM-1 Phase 3 trial, Fedgchin et al. (2019) evaluated 346 participants randomized to esketamine (56 or 84 mg) or placebo nasal spray plus a newly initiated oral antidepressant, but statistical significance was not achieved on the primary endpoint for esketamine 84 mg plus antidepressant versus antidepressant plus placebo (least square means difference -3.2, 95% CI -6.88 to 0.45, 2-sided P = .088). Neither trial determines whether co-administering these medications is safe or unsafe for an individual.

In patients aged 65 and older, Section 8.5 of the Spravato label states that four weeks of esketamine plus an oral antidepressant did not produce a statistically significant difference on the MADRS compared to placebo spray plus an antidepressant. In the SUSTAIN-1 trial (Daly et al., 2019, published in JAMA Psychiatry), continuing esketamine nasal spray alongside ongoing oral antidepressant therapy produced clinically meaningful superiority in delaying relapse compared to an oral antidepressant alone. Because oral antidepressants were continued across all arms in SUSTAIN-1, the trial did not assess esketamine monotherapy in preventing relapse.

Effects of Concurrent Medications on Ketamine Outcomes

We did not find a published study that isolates ongoing SSRI use as a factor in ketamine response. This search was not exhaustive. The studies we found on concurrent medications examine benzodiazepines.

In 2015, Frye and colleagues published a letter titled Concomitant benzodiazepine use attenuates ketamine response: implications for large scale study design and clinical development. Andrashko et al. (2020), in a retrospective study of 47 patients published in Frontiers in Psychiatry, evaluated ketamine administered as an add-on to existing antidepressant therapy. The authors concluded that higher doses of concurrent benzodiazepines were associated with poorer clinical outcomes, noting their data indicated a potential attenuation of ketamine's antidepressant efficacy. Feeney et al. (2022), a secondary analysis of the RAPID trial, found no difference in response by benzodiazepine use as a yes/no factor, but higher doses were associated with less improvement at day 1 and not at day 3.

Two esketamine analyses point in different directions. In a pooled post-hoc analysis of 451 patients across two esketamine clinical trials for major depressive disorder with acute suicidal ideation (published in Neuropsychiatric Disease and Treatment in 2021), researchers found that concurrent benzodiazepines did not meaningfully affect the 24-hour antidepressant response to esketamine, although higher sedation rates were observed. In a naturalistic retrospective study of 178 patients receiving subcutaneous esketamine (Journal of Affective Disorders, 2026), concurrent benzodiazepine use was linked to higher depressive severity scores, whereas co-administered lithium and lamotrigine were not associated with different symptom trajectories (authors called for prospective studies). For patients reviewing pharmacology comparisons, our ketamine vs antidepressants guide examines how ketamine differs from daily oral antidepressants.

Evaluating Serotonin Syndrome Evidence

A frequent clinical question regarding ketamine and SSRI combinations is whether pairing them creates a risk for serotonin syndrome. According to the National Library of Medicine via MedlinePlus, serotonin syndrome is a potentially life-threatening medical reaction caused by excessive serotonin accumulation in the body. MedlinePlus explains that the condition occurs most frequently when two or more substances that alter serotonin levels are taken simultaneously, citing the combination of SSRIs and triptans as an example. MedlinePlus adds that it is more likely when a person first starts a medicine or raises the dose.

The National Institute of Mental Health (NIMH) similarly notes on its mental health medications resource page that combining antidepressants with other serotonergic agents, such as triptans or St. John's wort, can trigger rare but life-threatening serotonin syndrome. NIMH says that for most people the risk of such reactions is low. In that sentence NIMH names triptans and St. John's wort and does not name ketamine or esketamine; NIMH does not say whether ketamine or esketamine with an SSRI carries this risk.

In a 2024 case report and literature review (PMID 38819248), Deka et al. documented a 72-year-old woman who developed recurrent serotonin syndrome on two occasions in similar circumstances involving the administration of ketamine for electroconvulsive therapy (ECT). In their literature review, the authors found five cases in which serotonin syndrome was associated with ECT and one case linking ketamine to serotonin syndrome.

This was an ECT setting, not outpatient esketamine use. No source we reviewed settles serotonin syndrome risk for outpatient ketamine or esketamine combined with an SSRI. Readers seeking general safety guidance can consult our psychedelic medication safety guide and medication safety checker.

What NIMH and MedlinePlus Say About Stopping an Antidepressant

If you take an SSRI and are considering ketamine or Spravato, ask your prescriber before changing it. NIMH says people should not stop a prescribed medication, even when feeling better, without a health care provider. The agency emphasizes that stopping a medication too soon may cause unpleasant or harmful side effects.

MedlinePlus, discussing the packaging warning for triptans taken with SSRIs, says not to stop taking your medicine and to talk to your health care provider about your concerns first. NIMH adds that a provider can adjust the treatment plan if a medication is to be changed.

NIMH describes esketamine as an FDA-approved nasal spray indicated for treatment-resistant depression in adults who have not seen symptom improvement after trying at least two prior antidepressants. NIMH states that esketamine is delivered in a health care provider's office, a clinic, or a hospital, and patients usually continue their oral antidepressant to maintain clinical improvement over time. Readers evaluating other psychedelic interactions can consult our psilocybin and SSRI guide and our MDMA and SSRI guide.

Verdict: Prescriber Direction and Clinical Evidence

The Spravato label says it is used alone or with an oral antidepressant, and its interaction section does not name SSRIs. We found no source that shows an SSRI changes the effect of ketamine or esketamine, and none that settles serotonin syndrome risk for outpatient use with an SSRI. Whether to combine them, and any change to an antidepressant, is your prescriber's decision. In the label's Study 1, the newly initiated oral antidepressant was an SSRI in 32 percent of patients and an SNRI in 68 percent.

The label and trial evidence here applies to esketamine nasal spray (Spravato) in adults with treatment-resistant depression. No source we reviewed covers racemic ketamine taken with an SSRI; that decision is for the prescriber. The answer would change if a study isolates SSRI use as a factor in ketamine or esketamine response or safety (in either direction), if a source settles outpatient serotonin syndrome risk, or if the Spravato label adds serotonin-related text. For all personalized clinical decisions, consult your licensed medical prescriber, and review our ketamine side effects guide to see reported adverse events.