Ketamine has emerged as a treatment for depression, particularly for individuals who have not found relief from conventional therapies. The success of this treatment is closely tied to the careful determination of dosage, which is tailored to balance effectiveness with patient safety in a controlled medical environment.
Administration Routes and Typical Dosing
The method of delivering ketamine directly influences its dosage. Intravenous (IV) infusion is a prevalent method valued for the precise control it offers over the administration rate. For treatment-resistant depression, a common starting dose is 0.5 milligrams per kilogram (mg/kg) of body weight, infused slowly over approximately 40 minutes.
This IV dosage became a standard after clinical trials demonstrated its effectiveness. While 0.5 mg/kg is common, research has explored a range of doses, from 0.1 mg/kg up to 0.75 mg/kg, to accommodate patient needs. For patients with a high body mass index, clinicians may calculate the dose based on ideal body weight to avoid overmedication.
A distinct approach involves intranasal esketamine, available under the brand name Spravato. This FDA-approved treatment differs in its dosing structure, as it is administered in fixed doses of either 56 mg or 84 mg instead of being calculated by body weight. This product must be used within a certified healthcare facility where patients can be monitored.
Beyond medically supervised routes, compounded ketamine is prescribed for at-home use in forms like sublingual troches. This represents an “off-label” application. Doses for these formulations can vary widely, determined by the prescribing physician and the compounding pharmacy, and are intended to maintain therapeutic effects between clinical treatments.
The Treatment Protocol
The administration of ketamine for depression follows a structured timeline to maximize its benefits. The process is divided into two primary stages: an induction phase and a maintenance phase. Each stage has a distinct frequency and purpose.
The initial stage is the induction phase, characterized by frequent treatments intended to quickly reduce the severity of depressive symptoms. Patients undergo sessions two to three times per week for several weeks, such as one protocol involving six infusions over a two-week period. The objective is to achieve a rapid antidepressant response.
Following a successful induction, the patient transitions to the maintenance phase. The goal is to preserve the improvements gained and prevent relapse. The frequency of treatments is gradually reduced, tailored to the individual’s response, moving from weekly to bi-weekly, and then to monthly appointments.
Patient safety is managed through consistent clinical monitoring. All ketamine administrations, whether IV or intranasal, occur in a healthcare setting where medical professionals can observe the patient. Vital signs such as heart rate and blood pressure are tracked during and after the session to manage any immediate side effects.
How Individual Doses Are Determined
While standard dosing guidelines provide a starting point, the final ketamine dose is highly individualized through a process called titration. Clinicians begin with a typical dose and then carefully adjust it based on a collection of specific patient-related factors. This personalization is what allows the treatment to be optimized.
The most significant factor in dose adjustment is the patient’s therapeutic response. Clinicians monitor the impact of the initial doses on depressive symptoms, often using standardized rating scales. If a patient shows a robust response, the dose may be maintained, but if the response is insufficient, a provider might consider a gradual increase.
Tolerability is another consideration that runs parallel to effectiveness. The presence and severity of side effects like nausea, dizziness, or a temporary increase in blood pressure play a part in dosing. If a patient finds these side effects or dissociative feelings distressing, the clinician may reduce the dose or slow the infusion rate.
Body weight is a foundational element for calculating IV ketamine doses, but it is just one piece of the puzzle. The initial calculation is a starting point, not a fixed rule. The provider synthesizes information on symptom response, side effects, and patient history to arrive at a dose tailored to that individual’s needs.
Therapeutic vs. Anesthetic Dosing
A common source of concern for patients is ketamine’s history as an anesthetic. It is important to understand that the doses used to treat depression are significantly lower than those used to induce anesthesia. These doses are referred to as sub-anesthetic.
In a therapeutic setting for mental health, a typical intravenous dose is around 0.5 mg/kg. Some studies have found therapeutic benefits at doses as low as 0.1 mg/kg to 0.2 mg/kg. These low doses are sufficient to produce neurochemical changes without causing a loss of consciousness.
In contrast, anesthetic doses of ketamine are much higher. When used for surgical procedures, doses can range from 1 mg/kg to 4.5 mg/kg administered intravenously, several times the amount used in depression treatment. This higher dose is meant to induce unconsciousness and immobility.
This substantial difference in dosage is the primary reason why the side effect profiles for the two uses vary. While therapeutic doses can cause temporary psychological and physical effects, they are managed in a controlled setting. Anesthetic doses carry a different set of risks and require more medical support, such as respiratory assistance.