Ketamine Therapy Guide

1. What Is Ketamine Therapy?

Ketamine therapy involves the administration of sub-anesthetic doses of ketamine to treat psychiatric and pain conditions. Originally developed as an anesthetic and approved by the FDA for that purpose in 1970, ketamine has been used off-label for depression since the early 2000s after a landmark 2000 study by Berman et al. demonstrated its rapid antidepressant effects.[2]

The field gained significant momentum in 2006 when Zarate et al. published a randomized, placebo-controlled, crossover trial in the American Journal of Psychiatry demonstrating that a single IV ketamine infusion at 0.5 mg/kg produced rapid antidepressant effects within hours in patients with treatment-resistant depression (TRD) — effects that lasted up to one week.[3]

In 2019, the FDA approved Spravato (esketamine nasal spray), a derivative of ketamine, for treatment-resistant depression. This approval marked a milestone as the first new mechanism of action for depression treatment in over 30 years. In 2020, Spravato received an expanded indication for major depressive disorder with acute suicidal ideation or behavior.[4]

2. Mechanism of Action

Ketamine is a non-competitive NMDA (N-methyl-D-aspartate) receptor antagonist. Its antidepressant mechanism differs fundamentally from traditional antidepressants (SSRIs, SNRIs), which primarily target serotonin and norepinephrine systems and require 4–8 weeks to reach full efficacy.

Ketamine’s rapid antidepressant effects are attributed to a cascade of neuroplasticity-related changes:[5]

• NMDA receptor blockade on GABAergic interneurons, leading to a burst of glutamate release
• AMPA receptor activation, triggering downstream signaling through the mTOR pathway
• Increased BDNF (brain-derived neurotrophic factor) expression
• Rapid synaptogenesis — the formation of new synaptic connections, particularly in the prefrontal cortex
• Restoration of synaptic connectivity lost during chronic stress and depression

This mechanism explains why ketamine can produce antidepressant effects within hours, in contrast to the weeks required by conventional antidepressants. The mTOR-mediated synaptogenesis pathway is considered the primary driver of ketamine’s therapeutic effects.[6]

3. Types of Ketamine Treatment

Five forms of ketamine therapy are currently available in the United States, each with distinct advantages, limitations, and cost profiles:

3.1 IV Ketamine Infusion

Intravenous ketamine infusion delivers ketamine directly into the bloodstream for the fastest onset and most precise dosing control. It is the most extensively studied form of ketamine therapy for depression, with dozens of randomized controlled trials published since 2006.

• Dose: 0.5 mg/kg over 40 minutes (standard for depression)
• Bioavailability: 100%
• Cost: $400–$800 per session
• FDA status: Off-label for psychiatric use
• Response rate: 60–70% for treatment-resistant depression[7]

Learn more about IV ketamine infusion →

3.2 Spravato (Esketamine Nasal Spray)

Spravato is the only FDA-approved ketamine-based treatment for psychiatric conditions. It contains esketamine, the S-enantiomer of ketamine, which has higher NMDA receptor binding affinity than racemic ketamine. Spravato must be administered at certified REMS treatment centers.

• Dose: 56 mg or 84 mg nasal spray
• Bioavailability: ~48% (intranasal)
• Cost: $590–$885 per session (often covered by insurance)
• FDA status: Approved for TRD (2019) and MDD with suicidal ideation (2020)[4]
• REMS centers: Over 3,302 certified locations nationwide

Learn more about Spravato →

3.3 IM Ketamine Injection

Intramuscular injection offers comparable bioavailability (~93%) to IV with simpler administration. It is favored in many KAP settings and is typically more affordable than IV infusions.

• Dose: 0.5–1.0 mg/kg
• Bioavailability: ~93%
• Cost: $250–$500 per session
• FDA status: Off-label for psychiatric use

Learn more about IM ketamine →

3.4 Ketamine-Assisted Psychotherapy (KAP)

KAP combines sub-anesthetic ketamine with guided psychotherapy, following a three-phase structure: preparation, medicine session, and integration. It is particularly effective for trauma-related conditions like PTSD.[8]

• Session length: 2–4 hours
• Cost: $500–$1,500 per session
• FDA status: Off-label

Learn more about KAP →

3.5 Oral & Sublingual Ketamine

Oral ketamine lozenges (troches) are the most affordable and accessible form of ketamine therapy, often prescribed through telehealth platforms for at-home use after an initial evaluation.

• Bioavailability: ~25–30% (sublingual)
• Cost: $100–$250 per month
• FDA status: Off-label

Learn more about oral ketamine →

4. Standard Treatment Protocols

While protocols vary by provider and patient, the following are widely adopted standards:

IV Ketamine Protocol for Depression

• Induction phase: 6 infusions over 2–3 weeks (typically 3 per week)
• Dose: 0.5 mg/kg IV over 40 minutes
• Maintenance: Booster infusions every 3–6 weeks as needed
• Monitoring: Heart rate, blood pressure, oxygen saturation throughout
• Post-infusion observation: 30–60 minutes before discharge

Spravato (Esketamine) Protocol

• Induction (weeks 1–4): 56 mg or 84 mg twice weekly
• Weeks 5–8: 56 mg or 84 mg once weekly
• Maintenance (week 9+): 56 mg or 84 mg weekly or every 2 weeks
• REMS monitoring: Mandatory 2-hour post-dose observation at certified facility
• Driving restriction: No driving for the remainder of the treatment day

Chronic Pain Protocol

For chronic pain conditions (CRPS, fibromyalgia, neuropathic pain), higher doses and longer infusion times are used. Typical protocols involve infusions at 0.5–1.0 mg/kg/hour over 4–6 hours, sometimes over multiple consecutive days. These infusions are often administered in hospital or ambulatory surgery center settings.

5. Conditions Treated

Ketamine therapy is used for the following conditions, with varying levels of clinical evidence:

6. Costs and Insurance Coverage

Insurance coverage for Spravato: Most major commercial insurers (Blue Cross Blue Shield, Aetna, UnitedHealthcare, Cigna), Medicare Part D, and Medicaid (in most states) cover Spravato with prior authorization. Patients must typically demonstrate documented failure of at least 2 adequate antidepressant trials. The Janssen Savings Program offers $0 copay for eligible patients with commercial insurance.

HSA/FSA: All forms of ketamine therapy are generally eligible for HSA and FSA reimbursement as qualified medical expenses.

7. Who Is Eligible for Ketamine Therapy?

Eligibility criteria vary by provider, but general guidelines include:

Typical Requirements

• Age 18 or older (some providers treat adolescents under specific protocols)
• Diagnosis of a qualifying condition (TRD, PTSD, chronic pain, etc.)
• For Spravato: documented failure of at least 2 adequate antidepressant trials
• Stable medical condition allowing treatment in an outpatient setting
• Ability to arrange transportation (no driving on treatment days)

Common Contraindications

• Uncontrolled hypertension (ketamine transiently raises blood pressure)
• Active psychosis or schizophrenia (ketamine can worsen psychotic symptoms)
• Aneurysmal vascular disease or arteriovenous malformation
• Unstable cardiovascular disease
• Active substance use disorder (some providers will treat with additional monitoring)
• Pregnancy or breastfeeding
• Known ketamine hypersensitivity

8. Side Effects and Safety

The following side effects are commonly reported during ketamine therapy sessions. Most resolve within 1–2 hours after treatment:

Long-term safety: The SUSTAIN-2 open-label study of Spravato demonstrated a consistent safety profile over 1 year of treatment with no new safety signals. Long-term risks of repeated ketamine use at sub-anesthetic doses may include bladder toxicity (cystitis), though this is primarily observed at much higher recreational doses. Potential for psychological dependence exists but remains low under supervised medical protocols.[11]

9. Finding a Provider

When choosing a ketamine therapy provider, consider the following criteria:

• Medical credentials: Board-certified psychiatrist, anesthesiologist, or physician with ketamine-specific training
• Treatment setting: Clinical environment with vital sign monitoring, emergency protocols, and resuscitation equipment
• Spravato certification: For Spravato treatment, the facility must be REMS-certified
• ASKP membership: Membership in the American Society of Ketamine Physicians suggests adherence to professional standards
• Transparent pricing: Clear, upfront pricing with no hidden fees
• Follow-up protocols: Ongoing assessment and maintenance planning