Ketamine vs. Esketamine (Spravato): What the Difference Actually Means

Two Related Compounds, Not the Same Drug

Ketamine is a racemic mixture, meaning it contains two mirror-image molecules in equal parts: R-ketamine and S-ketamine (also called esketamine). Spravato, the brand-name nasal spray approved by the FDA in 2019, contains only the S-enantiomer. That isolation is the core pharmacological distinction between the two.

Preclinical studies showed that S-ketamine binds more potently to NMDA receptors, which is why it was isolated for development as a psychiatric medication. However, more recent animal research has suggested that R-ketamine may produce longer-lasting antidepressant effects with fewer psychotomimetic side effects. The picture is more complicated than “S is better.” Both compounds, and racemic ketamine as a whole, remain under active study.

Both substances are DEA Schedule III controlled substances. Both carry abuse and diversion potential. Neither is something you take home and self-administer. That is a point worth emphasizing clearly: both require clinical supervision, and for Spravato, the FDA’s REMS (Risk Evaluation and Mitigation Strategy) program mandates that every session take place in a certified healthcare facility with at least two hours of post-dose monitoring.

How Each Is Administered

IV ketamine is delivered intravenously over roughly 40 to 60 minutes in a clinical or hospital setting. Some clinics also offer intramuscular (IM) administration. The infusion delivers the drug directly into the bloodstream, producing more predictable plasma concentrations and, according to some comparative data, faster onset of symptom relief after the first session.

Spravato is self-administered as a nasal spray under clinical observation. The patient applies the spray and then remains monitored at the facility for at least two hours before being cleared to leave. They must arrange their own transportation home. The dosing schedule for treatment-resistant depression is twice weekly for four weeks, then weekly for four weeks, then biweekly or weekly for maintenance. Because it is a named schedule with FDA-defined protocols, the treatment pathway is more structured than IV ketamine, which has no single recommended dosing protocol.

What the Evidence Shows So Far

Both treatments have shown meaningful benefits for treatment-resistant depression (TRD), a condition generally defined as an inadequate response to at least two adequate antidepressant trials. The comparison between them is genuinely unsettled at this point, and anyone who tells you one is definitively superior to the other is overstating what the research currently supports.

A 2025 analysis from McLean Hospital found that patients receiving IV ketamine showed slightly greater symptom improvement (49.2%) compared to those on intranasal esketamine (39.6%). A separate retrospective chart review from the same year found that IV ketamine was associated with higher rates of adverse events, including dissociation (58% vs. 34%), hypertension (45% vs. 9%), and sedation (50% vs. 27%) compared to Spravato. That tradeoff matters clinically. A well-powered head-to-head randomized trial (NCT06713616, Yale University) launched in early 2025, but results are not expected before 2028 at the earliest. In the meantime, treatment decisions necessarily involve some uncertainty.

Both compounds act primarily through NMDA receptor antagonism, both produce rapid antidepressant effects relative to conventional medications, and both require careful patient selection and clinical oversight to be used safely.

Risks, Safety Profile, and Contraindications

The shared side effect profile for ketamine and esketamine includes dissociation, dizziness, nausea, elevated blood pressure, and sedation. These effects are generally transient, resolving within a few hours of the session. Both carry risks of abuse and dependence given their Schedule III classification, and both are contraindicated or require careful evaluation in patients with certain histories.

Key contraindications and cautions that apply to both treatments include: uncontrolled hypertension, a personal or family history of psychosis or schizophrenia, active substance use disorder (particularly stimulant or dissociative drug use), unstable cardiovascular disease, and certain thyroid conditions. Pregnancy and breastfeeding also preclude use. Spravato carries additional FDA boxed warnings for sedation, dissociation, and risk of abuse and misuse, which is why the REMS program exists.

If you are exploring either option and are unsure whether your health history creates specific risks, the contraindications guide published on this site on May 20 covers the landscape in more detail: Contraindications for Psychedelic Therapy. That post is worth reading before you move forward with any clinical inquiry.

A note on psychological readiness: neither treatment is a passive intervention. Both produce altered states. Dissociation is common and can be disorienting. Having professional support before, during, and after the experience is not optional from a safety standpoint; it is part of what makes these treatments viable rather than risky.

Legal Status

IV ketamine is FDA-approved as an anesthetic, but its use for depression and other psychiatric conditions is off-label. Off-label prescribing is legal and common in medicine, but it means there is no FDA-regulated protocol governing how it is administered for psychiatric purposes. Practices vary widely between clinics.

Esketamine (Spravato) received FDA approval in March 2019 specifically for treatment-resistant depression in adults, and later received an additional indication for major depressive disorder with acute suicidal ideation or behavior. Its legal pathway is clearly defined, which has downstream implications for insurance coverage and clinical standardization.

The Insurance Question: Where Things Diverge Most Clearly

When people ask about Spravato vs. ketamine infusion, the most practically significant difference often comes down to cost and insurance. This is where the FDA approval gap has real financial consequences.

IV ketamine for depression remains off-label, and as of 2025, most major commercial insurers explicitly exclude it from covered benefits. Patients typically pay $400 to $800 per session out of pocket. An initial induction series of six to eight sessions means upfront costs of $2,400 to $6,400, with ongoing maintenance sessions adding to that. Some insurers, notably Blue Cross Blue Shield of Massachusetts, do cover IV ketamine under specific medical necessity criteria, and Veterans Affairs provides coverage for eligible veterans. However, these are exceptions rather than the rule.

Esketamine therapy insurance coverage is substantially better because of FDA approval. Major insurers including Aetna, Cigna, UnitedHealthcare, Anthem, and Blue Cross Blue Shield plans cover Spravato when patients meet eligibility criteria. Medicare Part B covers 80% of costs after the deductible for sessions administered in certified facilities. Medicaid coverage varies by state.

The standard prior authorization criteria across most plans require: a confirmed diagnosis of TRD or MDD with acute suicidal ideation, documented evidence that at least two different antidepressants from different classes were tried at adequate doses without sufficient response, and treatment at a REMS-certified facility. The prior authorization process typically takes one to four weeks, so planning ahead matters. When coverage is approved, most commercially insured patients pay copays of $10 to $50 per session. The manufacturer’s copay assistance program (Janssen SpravatowithMe) can bring costs to as low as $10 per session for eligible commercially insured patients, with up to $8,150 in annual benefit.

Without insurance, Spravato runs $590 to $1,200 per session depending on dosage and facility fees. With coverage in place, the cost difference between the two options becomes significant. For many patients, this practical factor ends up driving the decision as much as any clinical consideration.

When Each Option Tends to Make More Sense

IV ketamine may be worth considering when a patient needs faster onset of response (some comparative data suggests it produces greater improvement after the first session), when esketamine insurance coverage is denied or unavailable, or when a prescribing provider has specific clinical reasons to prefer systemic delivery. Some providers also consider it when a patient cannot tolerate nasal administration or has anatomical factors that affect intranasal drug delivery.

Spravato tends to be the more practical path when insurance coverage can be secured, when a patient values the more standardized dosing protocol, or when the lower side-effect burden observed in some comparative studies is a priority. The REMS program, while administratively demanding, also provides a layer of clinical oversight that some patients find reassuring.

Neither option should be approached as a standalone treatment. The research supporting ketamine-based interventions consistently points to better outcomes when they are embedded in a broader therapeutic context, including preparation, professional support during the experience, and structured integration afterward. The altered states produced by both treatments can surface material that deserves thoughtful attention. That is not incidental to the process. For many people, it is central to it.

What to Ask Before You Start

If you are considering either treatment, a few questions are worth raising with any provider you consult: Is your facility REMS-certified for Spravato? What is the side-effect management protocol during and after sessions? How do you handle patients who have a difficult psychological response? What does the integration support look like? What happens if I need to stop treatment?

The answers to those questions will tell you as much about whether a clinic is the right fit as any clinical brochure will.