Study: Experimental sleep drug may cause fewer side effects

Bottle of tablets (Ben Richardson)

(Reuters) - A study in rats and monkeys suggests an experimental Merck & Co. sleep drug may help induce sleep without causing the memory loss and attention problems sometimes seen in the commonly used drugs Ambien and Lunesta, company researchers said on Wednesday.

Experiments in animals suggest Merck's sleep drug Suvorexant, now before the U.S. Food and Drug Administration, may avoid these side effects, the company said.

Insomnia affects about 10 percent of U.S. adults, and roughly a third of these individuals take drugs to help them sleep. Most sleep aids, including Sanofi's Ambien or Sunovion Pharmaceuticals' Lunesta, act on a key neurotransmitter in the brain called GABA.

"These treatments work by forcing the brain to go to sleep," said study leader Jason Uslaner of Merck in an interview on the website of Science Translational Medicine, which published the study.

GABA receptors are important to many brain regions, including those important for cognition, which is likely why common sleep aids can cause memory loss and attention problems.

"When you hit those, you don't just hit the sleep system," John Renger, executive director and head of neruoscience basic research at Merck and one of the study's authors, said in a telephone interview.

Suvorexant is part of a class of drugs called Dual Orexin Receptor Antagonists or DORAs, which work by blocking chemical messengers called orexins. Orexins are responsible for keeping people awake. Levels of this compound rise during the day and fall at night.

Orexins originate in a specific region of the hypothalamus, so targeting them may have less impact on other brain functions, Renger said.

For this study, the team wanted to find out what would happen if someone is awakened on this drug and has a very high level of it in their system.

Follow this link:
Study: Experimental sleep drug may cause fewer side effects