What is ketamine?
Ketamine is widely used in general hospitals across the world as an anaesthetic. The dose of ketamine used in anaesthesia is higher than the dose being used to treat depression. Repeated high doses of ketamine are commonly given. In some centres, ketamine is given repeatedly to patients with depression who are having electro-convulsive therapy.
There is now a growing body of evidence to suggest that low dose ketamine infusions can have antidepressant effects in patients with TRD.
Ketamine often cannot be used in people with serious cardiac disease, uncontrolled high blood pressure, porphyria or acute stroke.
What are the side effects of ketamine treatment?
At high doses, ketamine commonly causes brief side effects including feeling ‘spaced out’ or drunk. Patients sometimes report that ‘things look peculiar’ or have hallucinations. Sometimes patients feel sick. At high doses these effects sometimes continue for a few hours.
Ketamine is sometimes used as a drug of abuse because of the effects it has at high doses. It is not addictive.
At the lower dose used to treat patients with resistant depression, more mild symptoms of feeling ‘spaced out’ or drunk, or of visual distortions also sometimes occur. They last no more than 90 minutes.
The treatment involves having a needle put into a vein on the back of the hand and a low dose of ketamine infused over 40 minutes. As a result, there is a chance that temporary bruising may occur at this site.
Anaesthetic dose: 1-4.5 mg per kg
Recreational (illegal) dose: 1-2 mg per kg
Dose used to treat depression: 0.5mg per kg over 40 minutes