The anesthetic ketamine has provoked excitement in recent years as a fast and effective treatment for major depression. Now, a small new study provides information on the mode of action of the drug for the treatment of depression with a surprising finding: Ketamine must activate opioid receptors in order to be able to antidepressant.
The new findings challenge earlier views The drug works against depression, the researchers said. "It does not work as if everyone thought it would work," said co-senior study author Dr. Alan Schatzberg, Professor of Psychiatry and Behavioral Sciences at the Faculty of Medicine of Stanford University, in a statement. The current opioid epidemic highlights the need to prevent depression and widespread ketamine ingestion. Englisch: dermis.multimedica.de: 80 / dermisroot … iagnosep.htm warn them to better investigate the mechanism of action of the drug and the risk of abuse in patients. "We need to properly investigate the risks associated with the use of drugs of abuse, even in low doses, to treat depression," said Schatzberg. [6 Party Drugs That May Have Health Benefits]
The study was published today (August 29) in the American Journal of Psychiatry.
Ketamine for Depression
Ketamine has been used as an anesthetic in hospitals for decades, but also has a reputation as an illegal "club drug" known as "Special K".
In recent years, studies have shown that ketamine can have quick and dramatic effects for people with depression who can improve symptoms within hours as weeks improve many other antidepressants. In light of these findings, the drug has proven to be a potentially promising therapy for people with severe depression who have not been helped by other treatments, and some doctors are prescribing the drug "off label" for depression.
Just like ketamine, depression is unknown. Researchers speculated, however, that the antidepressant effect of the drug is due to its ability to block the receptor for a brain chemical called glutamate, which is involved in mood regulation.
But as scientists tried to develop other glutamate receptor-blocking drugs to treat depression, these efforts largely failed, according to Schatzberg
In the new study, researchers hypothesized that ketamine was at least partially activated by activation Opioid receptors for the treatment of depression acts. To investigate this possibility, the researchers gave participants the opioid-blocking drug naltrexone before receiving ketamine treatment.
The study included 1
All participants received an infusion of ketamine twice – once after receiving naltrexone and again after receiving a placebo instead of the opioid blocker. The two infusions took place about a month apart. Neither the participants nor the researchers knew whether the patients had received naltrexone or placebo prior to their ketamine treatment.
The study found that subjects who received ketamine with placebo experienced a dramatic decrease in their depression symptoms they received naltrexone, which had almost no effect on their depressive symptoms.
Participants who received naltrexone, however, still experienced "dissociative effects" of ketamine such as hallucinations.
The findings were so clear that the researchers quit the study early to avoid exposing more people to "a clearly ineffective and harmful combination treatment," the researchers said, referring to the ketamine plus naltrexone treatment.
Since the new study was small, the results should be confirmed by further research, Dr. Ing. Mark George, a professor of psychiatry, radiology and neuroscience at the Medical University of South Carolina, wrote in an editorial accompanying the study. (George was not involved in the new study.)
More research is also needed to investigate whether the antidepressant effects of ketamine on its action on opioid receptors alone, its combined effect on opioid and glutamate receptors or
He also urged caution in the use of ketamine in depression. "We would hate treating the depression and suicide epidemics by over-use of ketamine, which may inadvertently grow the" third head "of opioid dependence," said George. He compared the problems of opioid use, depression and suicide with the heads of Hydra, the many-headed monster in Greek mythology.
"We need to understand the effects of ketamine better and how best to use and administer it." he concluded.
Original article by Live Science .