April 16 (UPI) -- A nasal spray mist form of ketamine, which has a history of recreational use, could help alleviate symptoms of major depression and suicide thoughts, according to results from a phase 2 study.
Researchers at Janssen Research and Development, Janssen Scientific Affairs and the Yale School of Medicine paired an intranasal formulation of esketamine, which is part of the ketamine molecule, with standard treatment for rapid treatment of depression and suicidal symptoms, comparing the outcome to that of standard treatment plus a placebo. Their findings were published Monday in the The American Journal of Psychiatry.
Used in powdered or liquid form, ketamine was listed as a Schedule III controlled substance in 1999 by the Drug Enforcement Administration. Ketamine, which is sold under the brand name Ketalar and others, can be injected, consumed in drinks, snorted or added to marijuana or tobacco cigarettes.
Sixty-eight participants were randomly assigned to one of two groups for medication twice a week for four weeks.
Depression scores and suicidal beliefs dropped faster in the esketamine group compared with the placebo group after four hours and after 24 hours. However, the esketamine effects weren't greater than the placebo after 25 days. The results from all three time periods were based on the patient's and clinician's perspectives.
The rapid effects are a key, researchers said, because most antidepressants take four to six weeks to become fully effective.
"All the studies to date have been looking at intravenous use -- there are some people who have explored oral ketamine but that doesn't appear to be as successful as intravenous so intranasal seems to be a really good halfway-house," Dr. Mitul Mehta from King's College in England told the BBC. "It enters the body relatively quickly -- it's not as fast as going straight into your bloodstream but not as slow as via the stomach and it's reasonably easy to control how much you give to a person. In that respect this is a really important study."
Ketamine can be used off-label for depression in the United States and Britain because it is an aneasthetic. Esketamine's use, however, must still go through a phase 3 study before possible Food and Drug Administration approval as a prescription.
The authors also note that more research is needed on the potential for abuse of ketamine.
In an accompanying editorial, researchers wrote that phase 3 trials need to monitor patients' craving and potential ketamine use from other sources.
Compared with studies on the effects of antidepressants, they wrote that "there is substantially less information on the beneficial and adverse consequences of repeated ketamine administration. This is of paramount importance, because the excitement about ketamine in our field is a reflection of the serious challenges we face in managing treatment-resistant depression."
The study authors said ketamine could "continue to be available to those with need, while the population that is at-risk for abuse is protected from an epidemic of misuse."
In two studies published in February in the Harvard Review of Psychiatry, researchers explained ketamine and related drugs may represent a "paradigm shift" as an antidepressant to rapidly treat major depressive disorder and bipolar depression, according to the National Institute of Mental Health.