Evaluation of the drug is much needed as some clinics offer repeated dosage without evidence of safety, says professor
The largest randomised double-blind trial to evaluate the effectiveness of ketamine as a new treatment for depression has begun in Australia and New Zealand.
Over the course of three years, researchers from the Black Dog Institute will analyse 200 adults who have not responded to existing medications for major depression, comparing the effects of twice-weekly ketamine treatment against a placebo over a four-week period.
The drug will be administered to patients via a needle into subcutaneous tissue.
Lead researcher, UNSW Professor Colleen Loo who is based at the Black Dog Institute, says previous studies have found a single dose of ketamine produces rapid antidepressant effects within hours, but achieving lasting effectiveness remains a challenge.
“This trial will allow us to examine the effects of repeated dosing and whether the positive effects of ketamine on an individual’s depression can be sustained over a longer period,” says Professor Loo.
Ketamine is already being used in Australian clinics to treat depression but without clinical evidence of its safety, so understanding the effects of repeated dosing is vital, she says.
“Some clinics in Australia and overseas continue to offer off-label ketamine treatments to patients with depression in an unsafe manner and with minimal care,” says Professor Loo.
“This practice is premature and irresponsible, given that the effectiveness and safety of this treatment approach involving repeated dosing has yet to be tested in controlled trials.
“We will be working very closely with clinical pharmacologists during this trial to understand the specific dosage required for each individual and the likely effects it will have,” she says.
Ketamine is known to target glutamate in the brain, as opposed to serotonin or noradrenaline with other antidepressants.
Studies have shown that the drug can have disorienting or dissociative side effects, which accounts for its use as a recreational drug, says the Black Dog Institute.
These are effects are short-lived, however, lasting about half an hour after each treatment while beneficial mood effects are known to persist for days.