NEW Australian research has found the party drug ketamine could be effective to treat depression in seniors.
The world-first study by the University of New South Wales and Black Dog Institute found that the anaesthetic ketamine, also used as a recreational street drug and animal tranquiliser, was effective as an antidepressant in elderly patients when delivered in repeated intravenous doses.
The trial tested different doses of ketamine among 16 participants aged over 60 who had treatment-resistant depression.
The university's Colleen Loo, who is based at the Black Dog Institute said the findings were a "big step forward " in understanding the potential and limitations of ketamine's antidepressant qualities.
"Not only was ketamine well-tolerated by participants, with none experiencing severe or problematic side effects, but giving the treatment by a simple subcutaneous injection (a small injection under the skin) was also shown to be an acceptable method for administering the drug in a safe and effective way," said Professor Loo.
Co-author Duncan George from UNSW said elderly patients with severe depression face additional barriers when seeking treatment.
"Many medications may cause more side effects or have lower efficacy as the brain ages," said Dr George.
"Older people are also more likely to have co-morbitities like neurodegenerative disorders and chronic pain, which can cause further complications due to ketamine's reported side effects."
He said a dose-titration method (the continual adjustment of a dose based on patient response) may be useful for older patients, to maximise the benefits of the ketamine while minimising its adverse affects.
Previous studies into ketamine treatments for older people with depression show mixed success. As such, little is known about ketamine's potential side effects at different doses, which include cognitive and disassociative effects, elevated blood pressure and heart rate, liver inflammation and urinary problems.
"The results are a promising early piece of the puzzle, but the risks of ketamine use of still not wholly understood," said Professor Loo.
She said future studies and greater sample sizes are needed to formally assess the side effects of ketamine, including its impact on the liver.
The study was a collaboration between UNSW, Black Dog Institute, Royal North Shore Hospital, The Wesley Hospital Kogarah, the Dementia Collaborative Research Centre and the University of Otago. The results were published in the American Journal of Geriatric Psychiatry.
- Professor Loo is recruiting participants for the world's largest trial of ketamine to treat depression. Phone (02) 9382-9509.