Ketamine Tablet Dose by Weight: How mg/kg Translates

Ketamine tablet doses are most often written as a flat milligram amount, but many published protocols and pharmacology references describe dosing in milligrams per kilogram of body weight (mg/kg). Understanding how those numbers translate to a compounded tablet helps you read your prescription and have a clearer conversation with your prescriber. Tablet dosing is always set by a clinician, but knowing the typical ranges makes the rationale less opaque.

This guide walks through how mg/kg ranges show up in oral ketamine dosing, why the same milligram dose can land differently in two people, and what the limits and contraindications look like in practice. Numbers below reflect ranges reported in published off-label protocols and case series — not a personal recommendation.

Why Weight Matters for Oral Ketamine Tablets

Ketamine distributes broadly through body water and lipid compartments, so larger bodies generally clear a larger absolute dose. When clinicians plan a tablet regimen, body weight is one of several inputs, alongside indication, prior ketamine exposure, comorbidities, and other medications. Weight-based dosing is most visible in IV and IM protocols, but the same logic informs starting tablet doses, especially for patients at the extremes of the weight range.

For oral and sublingual ketamine, bioavailability is markedly lower than IV — published values typically cluster around 15 to 25 percent for swallowed ketamine and around 25 to 30 percent for sublingual or oromucosal administration. That is why a tablet dose in milligrams looks much higher than the IV equivalent for a similar effect, even after accounting for body weight.

Typical mg/kg Ranges in Published Protocols

Published off-label protocols and case series for oral or sublingual ketamine in mood disorders most often report starting doses in the range of roughly 0.5 to 1.0 mg/kg, with some protocols going up to about 1.5 to 3.0 mg/kg per session as tolerance and response are established. Pain and palliative protocols sometimes use lower, more frequent doses.

These ranges are descriptive, not prescriptive. The same 100 mg tablet represents about 1.4 mg/kg for a 70 kg adult and about 1.0 mg/kg for a 100 kg adult, which is one reason two patients on the same milligram dose can have noticeably different experiences.

How Tablet Strengths Translate Across Body Weights

Because compounded ketamine tablets are typically supplied in fixed strengths — commonly 25 mg, 50 mg, 100 mg, and sometimes higher — clinicians often round to the nearest practical tablet rather than dose to an exact mg/kg target. The comparison table below shows roughly how a few common tablet doses map onto mg/kg for different body weights. It is illustrative only.

Why the Same mg/kg Dose Can Feel Different

Two patients dosed at the same mg/kg level may still have very different experiences. First-pass metabolism in the liver varies between individuals, so the fraction of a swallowed dose that reaches circulation is not identical from person to person. For sublingual or buccal administration, technique — how long the tablet is held in the mouth, whether saliva is swallowed early, and whether food or beverages are consumed too soon afterward — has a measurable effect on absorption.

Other medications can also shift the picture. Inhibitors and inducers of the CYP3A4 and CYP2B6 enzyme systems can raise or lower plasma ketamine concentrations. Discuss any new prescriptions, antifungals, certain antibiotics, antiretrovirals, and herbal products with the prescriber before changing dose.

Steps to Read a Tablet Dose in mg/kg Terms

If your prescriber gives you a flat milligram dose, this is a quick way to translate it into the weight-based language used in many references.

1. Convert your weight to kilograms (pounds divided by 2.2).
2. Take the prescribed milligram dose for a single session.
3. Divide the milligram dose by your kilogram weight.
4. The result is your approximate mg/kg dose for that session.
5. Repeat the calculation any time your weight or dose changes.
6. Confirm the number with your prescriber before relying on it.

Upper Limits and Safety Boundaries

Published protocols typically cap single oral or sublingual doses well below recreational ranges, and increases are usually made in small increments — often 25 to 50 mg per step — with a multi-day gap to assess response and side effects. Many programs set a per-session ceiling and a separate weekly ceiling, both of which are individualized.

Self-escalating above a prescribed dose is unsafe. It increases the risk of dissociation that exceeds the therapeutic window, transient blood pressure and heart rate elevations, nausea and vomiting, and impaired coordination. Any change to mg/kg should come from the prescribing clinician.

Contraindications and Cautions

Weight-based dosing does not override the standard contraindications. Ketamine tablets are generally avoided or used cautiously in people with uncontrolled hypertension, certain cardiovascular conditions, increased intracranial or intraocular pressure, active psychosis, current pregnancy, and a history of ketamine or other substance use disorder. Caution is also warranted with significant hepatic impairment, which can prolong exposure at any given mg/kg dose.

Liver and renal function, baseline blood pressure, mental health history, and a current medication list should be reviewed before any dose is set or adjusted. Older adults and people with low lean body mass may need lower starting points within the published range.