We are not talking about the cereal, folks. Here at Medgadget, we rarely venture into medication news. Yet this latest drug research is too exciting to pass by. Some of us here are anesthesiologists, after all. So here it is. Until now, there were only a few indications for ketamine. One indication was a ketamine dart to subdue an out of control rhinoceros at a local zoo. Another was a ketamine dart–and here comes the professional secret–for a mentally retarded patient who is to undergo general anesthesia, commonly for a dental cleaning, also known as “mental dental” among anesthesiologists. Ketamine is a general anesthetic, after all. The other, possibly most common use, is known as Special K. Drug users and abusers seem to enjoy–with eyes open–dissociative effects of ketamine, as well as withdrawal hallucinations.
Now comes a potentially huge new use for ketamine. From the National Institute of Mental Health media release:
People with treatment-resistant depression experienced symptom relief in as little as two hours with a single intravenous dose of ketamine, a medication usually used in higher doses as an anesthetic in humans and animals, in a preliminary study. Current antidepressants routinely take eight weeks or more to exert their effect in treatment-resistant patients and four to six weeks in more responsive patients – a major drawback of these medications. Some participants in this study, who previously had tried an average of six medications without relief, continued to show benefits over the next seven days after just a single dose of the experimental treatment, according to researchers conducting the study at the National Institutes of Health’s National Institute of Mental Health.
This is among the first studies of humans to examine the effects of ketamine on depression, a debilitating illness that affects 14.8 million people in any given year. Used in very low doses, the medication is important for research, but is unlikely to become a widely used clinical treatment for depression because of potential side effects, including hallucinations and euphoria, at higher doses. However, scientists say this research could point the way toward development of a new class of faster- and -longer-acting medications. None of the patients in this study, all of whom received a low dose, had serious side effects. Study results were published in the August issue of the Archives of General Psychiatry.
For this study 18 treatment-resistant, depressed patients were randomly assigned to receive either a single intravenous dose of ketamine or a placebo (inactive compound). Depression improved within one day in 71 percent of all those who received ketamine, and 29 percent of these patients became nearly symptom-free within one day. Thirty-five percent of patients who received ketamine still showed benefits seven days later. Participants receiving a placebo infusion showed no improvement. One week later, participants were given the opposite treatment, unless the beneficial effects of the first treatment were still evident. This “crossover” study design strengthens the validity of the results.
“To my knowledge, this is the first report of any medication or other treatment that results in such a pronounced, rapid, prolonged response with a single dose. These were very treatment-resistant patients,” said NIMH Director Thomas R. Insel, M.D.
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