Ketamine Dosage, Administration, and Effects

Ketamine Dosage & Administration

Ketamine can be administered in several ways, aside from oral administration (i.e. as a pill): Through the nose (i.e. as a nasal spray), and through intravenous infusion (IV). Though there are variations, the intravenous infusion often works the fastest, with the onset of action occurring in less than a minute. The bioavailability of ketamine, meaning the portion of it that reaches the circulation, is highest when administered intravenously.

Ketamine’s half-life is 2.5 to 3 hours. Half-life refers to the time it takes for the concentration of the medication to reach half its maximum concentration. Ketamine’s bioavailability is 93% when administered through IM, and considerably lower when administered through oral or nasal routes (below 50%). The metabolism of ketamine occurs primarily in the liver; its main metabolite is norketamine.

The dose for the infusion therapy for depression is usually 0.5-2.0 mg/kg body weight, administered over a period of 45 minutes. The treatment is usually repeated twice a week for three weeks. More frequent and long-term administrations of IV ketamine have also been documented.

Research continues to investigate what dosing protocol works best. This is particularly important given that there is a high risk for relapse and the return of depressive symptoms once the treatment stops. Aside from changing the dosing protocol, combining the treatment with psychotherapy may prevent relapse as well.

The Effects of Ketamine

Acute effects of ketamine—effects that occur immediately and last only a short time—range from barely perceptible to highly significant perceptual alterations. For instance, a patient receiving a low ketamine dosage may experience relaxation and a pleasant dream-like state, be vaguely aware of interesting changes in sensations and thoughts, and have mild feelings of euphoria.

As a drug that has received FDA’s schedule III designation, ketamine is considered to have low to moderate potential for dependence. For instance, some patients show tolerance to ketamine, meaning they show less of a response over time to the same dose. Nevertheless, when ketamine is used for medical purposes and administered according to the recommended guidelines, the likelihood of abuse and dependence is significantly reduced.

Ketamine’s immediate side effects

In general, at low doses (e.g., below 3 mg/kg), the following temporary side effects have been observed:

• Agitation
• Blurred vision
• Concentration problems
• Feelings of dizziness
• Dry mouth
• Headaches
• Impaired motor coordination
• Nausea
• Vomiting

These side effects commonly last only a few hours—sometimes longer, especially for people who are trying ketamine for the first time.

A rarely observed side effect involves a switch to a hypomanic or manic state. This occurs in some patients with bipolar disorder. A more commonly reported effect is called the emergence phenomena, an unpleasant experience of vivid dreams and hallucinations experienced while awakening from the effects of ketamine treatment. This side effect can be reduced or prevented by the administration of benzodiazepines. Due to these potential side effects, patients need to receive medical evaluations, including laboratory or imaging tests, before starting the ketamine treatment. It is important to note that many of the immediate side effects of ketamine infusion are temporary and manageable with medications. For example, antihypertensive medications are given to control high blood pressure, and anti-anxiety medications help patients cope with their psychological reactions to the treatment.

What is Treatment-Resistant Depression?

Treatment-resistant depression is a depression that has failed to respond to at least 3 antidepressant medications from different drug classes.

What is Spravato?

Spravato Nasal Spray is a new FDA approved medication for the treatment of chronic depression in adults. Please fill out the form to download our patient guide to get more information on this medication, who is the right candidate, treatment options, and potential side effects.

Talk to your doctor to see if Spravato is right for you.

Please note that Spravato can only be administered in a medically supervised healthcare setting that has been recognized as a certified treatment center.

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Psychiatrists Orange County CA
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