What Happens During a Ketamine Infusion?

A ketamine infusion dose for depression treatment is typically 0.5 mg/kg of body weight, delivered through an IV line over about 40 minutes in a monitored clinical setting. You stay conscious during the infusion but often experience dissociation, altered perception of time, and a dreamlike state as the medication takes effect. A clinical team checks your blood pressure, heart rate, and oxygen saturation throughout the appointment, and you rest in the clinic for another 1 to 2 hours afterward before you are cleared to leave. From arrival to discharge, the full visit usually takes 2 to 3 hours.

How the Ketamine Infusion Dose Is Determined

The 0.5 mg/kg dose used in most depression protocols comes from the early clinical trials on ketamine and mood disorders that established the subanesthetic infusion model still used today. A consensus statement from an APA task force on ketamine for mood disorders, indexed on PubMed, identifies this weight-based dose and 40-minute infusion time as the protocol with the strongest evidence base for treatment-resistant depression.

This dose is far below what is used for anesthesia, where ketamine is given in much larger amounts to induce unconsciousness, according to the National Library of Medicine's drug information. At 0.5 mg/kg, most patients remain alert and able to communicate with the clinical team while experiencing dissociative effects. Some clinics adjust the dose slightly, typically within a 0.5 to 1 mg/kg range, based on your medical history, prior response to treatment, and how well you tolerate the infusion. Your clinician calculates your exact dose using your current body weight, not a fixed amount, which is why an accurate weight measurement at the start of treatment matters. For context on how ketamine fits into care for difficult-to-treat depression, see the Mayo Clinic's overview of treatment-resistant depression.

Before the Infusion

When you arrive, a clinician reviews your medical history and current medications, then records baseline vital signs, including blood pressure, heart rate, and oxygen saturation. Most clinics advise avoiding food for 2 to 4 hours before treatment to reduce the risk of nausea. You will be seated in a reclining chair or bed in a private treatment room, often with an eye mask and headphones with calming music available if you want them.

This is also when your ketamine infusion dose gets finalized. Your clinician confirms your current weight and reviews any medications that could interact with ketamine before calculating the exact amount for your infusion pump. If you take other medications, ask your provider how they might affect your response; see our guide to ketamine drug interactions for more detail.

During the 40-Minute Infusion

An IV catheter is placed, usually in the hand or forearm, and the ketamine solution is delivered through an infusion pump that controls the exact rate over 40 minutes. Effects usually begin within the first 5 to 10 minutes.

Common experiences during the infusion include a feeling of floating or lightness, an altered sense of time, visual changes such as enhanced colors or softened edges, mild euphoria or emotional openness, and a sense of detachment from your surroundings. These dissociative effects are a normal part of the treatment and vary in intensity from person to person.

Vital signs are checked at regular intervals, typically every 15 minutes, throughout the infusion. Blood pressure commonly rises by 15 to 25 mmHg systolic during treatment, which is expected and monitored closely. Nausea occurs in an estimated 15 to 30 percent of patients and can be managed with antiemetic medication if needed. For a fuller rundown of what side effects to expect, see our safety and side effects guide.

After the Infusion

Once the infusion is complete, you remain in the clinic for a monitoring period of 1 to 2 hours. The dissociative effects typically fade within 60 to 90 minutes after the infusion ends. Vital signs are rechecked to confirm they have returned to an acceptable range before you are discharged.

You will not be allowed to drive yourself home; a pre-arranged ride is required. Most clinics recommend resting for the remainder of the day, and driving or operating machinery is restricted for 24 hours. Many patients report feeling emotionally lighter or notice the beginning of mood improvement later that day or the following morning, though the full antidepressant effect of a treatment course typically builds over multiple sessions. See how long ketamine effects last and how many treatments are typically needed for more on what to expect after your first infusion.