New Sleep Drug Does Well in Trial

Suvorexant for insomnia appears effective in small clinical trial

(RxWiki News) Most sleeping drugs try to treat insomnia by making a person sleepier. A new drug is being tested that works differently. Instead, it tries to reduce alertness to help you sleep.

The drug is called suvorexant. A recent small study conducted by the drug's manufacturer showed that suvorexant appears to help patients get better sleep in a four-week clinical trial.

There were no major side effects, but more research needs to be done to determine the drug's effectiveness.

"Ask your doctor about insomnia treatments."

The industry-funded study was led by W. Joseph Herring, MD, PhD, an employee at the pharmaceutical company Merck Sharp & Dohme Corp., which manufactures suvorexant.

All but one of the authors of the study is a Merck employee, and the non-employee author has received funds for research and consultancy for Merck. The study involved 228 patients suffering from insomnia who completed the full study (out of 254 who started).

The patients received either suvorexant or a placebo (fake pill) for one two-week period. Then, after a one-week break, those who previously had a placebo received suvorexant and those who had been given the placebo were then given suvorexant for another two-week period. The suvorexant was given in four doses: 62 patients were given 10mg, 61 were given 20mg, 59 were given 40mg and 61 were given 80mg.

The patients' sleep time was measured using polysomnography, which is a sleep lab test to see how much time the patient actually sleeps. The patients also filled out questionnaires about their sleep and how their insomnia interferes with daily activities.

The researchers assessed on how well the patients slept during the first night of the study and at the end of the fourth week, as well as when they woke up and how long it took them to fall asleep for good.

At the start of the study, the patients took an average of 69 minutes to fall asleep and slept an average total of 316 minutes.

During the first night of the study, patients taking 10mg got an average 25 minutes more of sleep. Those taking 20mg got an average 36 minutes more; those taking 40mg got an average 52 minutes more; those taking 80 mg got an average 62 minutes more.

At the end of week four, the average increased minutes of sleep were 22 (10mg), 50 (20mg), 37 (40mg and 80mg).

The patients also fell asleep an average of 10 to 38 minutes faster, depending on their dose and whether it was the start or end of the study.

According to William Kohler, MD, the director of the Florida Sleep Institute in Spring Hill, Florida, this study showing that suvorexant appears effective in treating insomnia is important because it introduces an alternative in treatment types from what is currently available.

"Most of the treatment we have available for insomnia uses drugs that work to help induce sleep. This particular drug works to reduce alertness," Dr. Kohler said. "It's a whole different mechanism of action."

He said this drug works by suppressing orexin, a chemical produced in the hypothalamus that increases alertness.

"By suppressing it, we theoretically could improve sleep," he said. But since this trial has a relatively small number of patients and only lasted four weeks, more research is necessary to see if this potential drug will work.

The most common side effects reported with suvorexant were drowsiness, headache, dizziness, odd dreams, upper respiratory tract infection, urinary tract infection and an increased amount of alanine aminotransferase, an enzyme related to the liver.

One person taking 80mg dropped out of the study because they had a mild visual hallucination lasting 30 to 60 minutes while trying to fall asleep. No serious adverse events were reported, including no sleepwalking and no reports of narcolepsy-like sudden daytime sleepiness. One person did have excessive daytime sleepiness once for four hours.

The study was limited by the small number of patients included, the short length of the study and the fact that it did not include elderly patients, since they frequently experience insomnia. The study was published November 28 in the journal Neurology. The research was funded by Merck Research Laboratories. All but one of the authors are Merck employees who own stock in Merck, which manufactures suvorexant.

The only author who is not a Merck employee has received research funding from 14 different pharmaceutical companies and consultancy fees from 58 pharmaceutical, manufacturing and/or medical product companies.

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Review Date: 
November 26, 2012