June 5, 2013
Low-Dose Anesthetic Shows Promise As Depression Treatment
redOrbit Staff & Wire Reports - Your Universe Online
New research funded by the Mayo Clinic suggests that low doses of a general anesthetic typically used during minor surgeries could be an effective treatment for depression.
According to the researchers, medical experts discovered approximately 10 years ago that ketamine had the potential to alleviate severe depression, but since the anesthetic can also have serious psychiatric side effects, they have been searching for a safe way to take advantage of its beneficial properties.
Now, writing in the latest edition of the Journal of Psychopharmacology, the Mayo Clinic team reports that low-dose intravenous infusions of ketamine administered over a sustained period of time could safely be used as a treatment for depression.
“It's surprising both that it works and how rapidly it has effects,” Mayo Clinic psychiatrist and study co-author Dr. Timothy Lineberry said in a statement. “It sometimes can work in hours to reduce depressive symptoms and suicidal ideation. Our goal is to begin to determine how the drug can be administered safely in routine treatment.”
Lineberry and his colleagues analyzed 10 patients with a severe depressive episode. Each episode resulted from either a major depressive disorder (MDD) or a type of bipolar disorder, and the patients participating in the study failed to find relief from a minimum of two anti-depressant medications.
During the trial, the patients were treated twice a week (up to a total of four treatments) with low-dose (0.5 mg/kg total dose) ketamine infusions given over a 100-minute period until their depression lifted.
The researchers said that their work demonstrates that when the anesthetic is administered at the lower rate, it is just as effective as when the infusions are given at higher rates. Furthermore, they monitored side effects using two different psychiatric scales — the Young Mania Rating Scale and the Brief Psychiatric Rating Scale.
“Eight of 10 patients showed at least 50 percent improvement. Five patients experienced complete remission of their depression, and four weeks after the study, two were still depression free,” the Mayo Clinic reported.
One patient experienced “brief and limited hallucinations,” they noted. The other study participants experienced no major side effects — only some drowsiness or dizziness — while receiving the infusions. The only question that remains, the researchers said, is determining which patients will respond best to the therapy.
“While patients and clinicians are excited about ketamine's potential, we know that much more research lies ahead before we know which depressive conditions can be addressed with ketamine safely by clinicians in routine clinical practice,” said Dr. Lineberry.