A standard initial course of ketamine therapy for depression consists of 6 intravenous infusions administered over 2 to 3 weeks, typically scheduled 2 to 3 times per week. After the initial series, most patients require ongoing maintenance infusions at intervals of every 2 to 6 weeks to sustain the antidepressant benefit. The exact number of treatments varies based on individual response, severity of symptoms, and treatment goals.
The Initial Treatment Course
The 6-infusion protocol over 2 to 3 weeks has become the most widely adopted initial treatment approach at ketamine clinics. This schedule is based on clinical experience and evolving research demonstrating that repeated infusions produce a cumulative therapeutic effect. Each successive treatment reinforces the neuroplastic changes triggered by ketamine, strengthening new synaptic connections and extending the duration of symptom relief.
Some patients experience significant improvement after just 1 or 2 infusions, while others may not notice clear benefit until the third or fourth session. Clinicians typically recommend completing the full 6-infusion series before assessing overall response, as early non-responders sometimes become responders with additional treatments. If a patient shows no improvement after 6 infusions, continued treatment with the same protocol is unlikely to be beneficial, and alternative approaches should be considered.
Maintenance Treatments
Because ketamine's effects are temporary -- a single infusion typically provides relief for 3 to 14 days -- most patients who respond to the initial series will need ongoing maintenance infusions. The frequency of maintenance treatments is individualized based on how long the benefit lasts for each patient.
Common maintenance schedules include:
- Every 2 weeks for patients whose symptoms return quickly
- Every 3 to 4 weeks for the majority of maintenance patients
- Every 5 to 6 weeks for patients with longer-lasting response
Clinicians use validated depression scales such as the PHQ-9 to track symptoms and adjust the maintenance schedule over time. Some patients find they can gradually extend the interval between treatments, while others maintain a stable schedule long-term. Combination approaches that pair ketamine with psychotherapy or optimized oral antidepressants may also help extend the interval between infusions.
For a full overview of treatment planning and protocols, see the Ketamine Dosing and Administration Guide.
References
- PubMed: Repeated Ketamine Infusions for Treatment-Resistant Depression — Review of repeated dosing protocols and cumulative efficacy
- NIH: Ketamine Research at NIMH — National Institute of Mental Health depression treatment research
- Mayo Clinic: Treatment-Resistant Depression — Overview of advanced treatment options including ketamine
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