Oral and Sublingual Ketamine

Overview of Oral and Sublingual Ketamine

Oral and sublingual ketamine represent alternative administration routes that offer practical advantages, particularly for maintenance therapy and at-home use. While IV infusion remains the most extensively studied method, oral and sublingual formulations have become increasingly popular due to their accessibility, lower cost, and convenience — especially in the context of telehealth-based ketamine therapy.

These formulations are compounded by specialty pharmacies and are prescribed off-label, as no oral or sublingual ketamine product has received specific FDA approval for psychiatric or pain indications. Despite their off-label status, they are widely used in clinical practice and supported by a growing body of evidence.

Sublingual Ketamine

What Is Sublingual Administration?

Sublingual administration involves placing a tablet, lozenge (troche), or dissolving film under the tongue, where the medication is absorbed through the mucous membranes directly into the bloodstream. This route bypasses the gastrointestinal tract and the liver's first-pass metabolism (at least partially), resulting in higher bioavailability compared to swallowed oral ketamine.

Sublingual Formulations

The most common sublingual formulations include:

• Troches (lozenges) — Compounded ketamine troches are the most widely prescribed sublingual form. They are typically held under the tongue or in the cheek for 10-15 minutes to maximize absorption, then the remaining saliva is either swallowed or spit out.
• Rapidly dissolving tablets (RDTs) — These tablets dissolve quickly under the tongue and are designed for consistent dosing.
• Oral dissolving films — Thin film strips that dissolve on the sublingual mucosa.

Bioavailability

Sublingual ketamine has an estimated bioavailability of 25-35%. This is lower than IV (100%) or intramuscular (93%) routes but higher than oral ingestion (approximately 17-24%). The onset of action is typically 10-20 minutes, with peak effects at 30-45 minutes and a total duration of 1-3 hours.

Dosing

Sublingual ketamine doses for psychiatric conditions typically range from 50 mg to 400 mg per session, depending on the patient's weight, tolerance, and clinical response. Dosing is highly individualized and is usually started at the lower end of the range with gradual titration upward.

Oral Ketamine

Swallowed Oral Ketamine

When ketamine is swallowed and absorbed through the gastrointestinal tract, it undergoes extensive first-pass metabolism in the liver. This process converts a significant portion of ketamine into its primary metabolite, norketamine, before it reaches systemic circulation. Norketamine has some pharmacological activity — for more on ketamine's metabolic pathways, see our pharmacology guide but is generally considered less potent than the parent compound.

Bioavailability

The oral bioavailability of ketamine is approximately 17-24%, meaning that a substantially higher dose must be given orally to achieve blood levels comparable to IV administration. The onset is slower (20-30 minutes), and the duration of effects is generally longer (2-4 hours) due to the gradual absorption and metabolism.

Oral Formulations

Oral ketamine is typically compounded as:

• Capsules — Standard gelatin or vegetarian capsules containing powder
• Liquid solutions — Ketamine dissolved in a flavored liquid base
• Troches intended for swallowing — Some practitioners prescribe troches with instructions to swallow rather than hold sublingually

At-Home Ketamine Therapy

The Telehealth Model

The growth of telehealth has facilitated a new model of ketamine therapy in which patients are evaluated remotely by a prescribing clinician, receive compounded oral or sublingual ketamine by mail from a specialty pharmacy, and self-administer at home under remote guidance.

This model has dramatically expanded access to ketamine therapy, particularly for patients in rural areas, those with mobility limitations, and individuals who cannot afford or access clinic-based IV infusions. However, it has also raised important questions about safety, supervision, and the potential for misuse.

Typical At-Home Protocol

A standard at-home ketamine protocol might include:

1. Initial evaluation — Comprehensive medical and psychiatric assessment (video or in-person)
2. Prescription — Sublingual troches or oral capsules prescribed at an individualized dose
3. Session preparation — Patient creates a safe, comfortable environment and has a sitter present
4. Administration — Patient takes the prescribed dose at the scheduled time
5. Monitoring — Some programs include remote check-ins via text or video during the session
6. Integration — Follow-up therapy or check-in to discuss the experience and assess response
7. Ongoing management — Regular follow-up appointments to adjust dosing and monitor for adverse effects

Safety Considerations for Home Use

At-home ketamine use requires careful attention to safety:

• A treatment sitter — an adult who remains present and sober during the session — is strongly recommended
• Patients should not drive, cook, or perform any potentially dangerous activities during or for several hours after treatment
• Ketamine must be stored securely and out of reach of children or others
• Patients should have a clear plan for contacting their provider or emergency services if needed
• Signs of developing tolerance or increasing use beyond prescribed parameters should prompt immediate clinical review

Comparing Administration Routes

Who Benefits from Oral/Sublingual Ketamine?

Oral and sublingual ketamine are particularly well-suited for:

• Maintenance therapy — Patients who have responded to an initial series of IV infusions and need ongoing treatment to maintain their gains
• Geographic barriers — Patients who live far from a ketamine infusion clinic
• Cost considerations — Patients for whom regular clinic visits are financially prohibitive (see our ketamine therapy cost guide for detailed pricing)
• Mild to moderate symptoms — Some clinicians use oral/sublingual ketamine as a first-line approach for less severe cases

For patients with severe, acute symptoms — particularly active suicidal ideation — IV infusion in a clinical setting remains the preferred initial approach due to its faster onset, higher bioavailability, and continuous medical supervision.

Conclusion

Oral and sublingual ketamine have expanded the reach of ketamine therapy significantly, making this treatment accessible to patients who would otherwise be unable to benefit. While these routes involve trade-offs in bioavailability and medical supervision compared to IV infusion, they represent a valuable and practical option when used appropriately under clinical guidance.

References

• StatPearls: Ketamine — Clinical reference covering ketamine pharmacology including oral and sublingual bioavailability
• Ketamine Pharmacology: An Update — NIH review of ketamine pharmacokinetics including first-pass metabolism and norketamine formation
• MedlinePlus: Ketamine Injection — National Library of Medicine drug information on ketamine clinical uses and safety
• FDA: Drug Information — U.S. Food and Drug Administration resource on drug regulation and off-label prescribing