Since the early 1990s, the most commonly prescribed sleeping pills have followed a formula that works by increasing levels of GABA, a neurotransmitter that slows down brain activity.
But a new insomnia treatment, Belsomra (suvorexant), is the first of its kind to do the opposite: Rather than increasing a neurotransmitter that slows brain activity, it decreases the neurotransmitter Orexin, which promotes wakefulness.
By turning off the brain's "awake" switch, Belsomra promotes sleep. And it's hugely popular, thanks in no small part to a major advertising push, which includes print ads, TV commercials featuring fuzzy creatures, online content (whyamisoawake.com) and an app called Sleep Guru.
Doctors were writing an average of 4,000 prescriptions each week, just a month after Belsomra, which is manufactured by Merck, was approved by the FDA last August.
Sales of the drug have been so successful that British consulting firm GlobalData predicts Belsomra will be the highest-selling insomnia medication within the next eight years. A considerable achievement given that more than 42 million sleep aid prescriptions were filled out in the U.S. alone last year.
But some sleep experts are worried that the drug's popularity is being driven by hype rather than real need. Clinical testing has shown that this new drug is no more effective than existing drugs, like Lunesta and Ambien. They've both been shown to be less effective (and potentially more costly) than cognitive behavioral therapy. This form of psychotherapy works to alleviate stress and anxiety, which can contribute to people finding it difficult to sleep at night.
As one cause of insomnia is wakefulness neurotransmitters being overactive at night, blocking these neurotransmitters should theoretically help reduce insomnia, according to Dr. Gregg Jacobs, an insomnia specialist at the Sleep Disorders Center at the UMass Memorial Medical Center.
"However, insomnia is caused largely by maladaptive sleep habits that indirectly increase wakefulness neurotransmitters, so targeting the neurotransmitters alone and not the maladaptive sleep behaviors is not likely to be effective," Jacobs told The Huffington Post in an email.
Although Belsomra was approved by the FDA, clinical trials found it has somewhat limited efficacy in treating insomnia.
"The drug barely improves sleep despite being incredibly expensive," Jacobs said. "At the 20 mg dose [the highest] that was approved by the FDA, people ... only obtained an extra 16 minutes of sleep. This is meaningless clinically." Participants also only fell asleep an average of six minutes faster than those who took a placebo.
While Belsomra is touted as having potentially less side effects than other sleep drugs, because it is more targeted, some critics have raised concerns about one major side effect: extreme drowsiness the next day.
In the FDA trials, participants who took the drug at the initial proposed doses, 30 to 40 mg, exhibited so much daytime drowsiness that the dosage was not approved. However, even at the 20 mg dose, some users still experienced next-day drowsiness, which can affect driving and decision-making, and may even lead to falls and impaired motor skills among older adults.
Drug safety experts Dr. Steven Woloshin and Dr. Lisa Schwartz told Consumer Reports that another troubling side-effect Belsomra users risk is feeling like they can’t move or talk.
Jacobs explained that it can take up to 72 hours to metabolize a single dose of Belsomra, which is why it can create a dangerous effect on next-day drowsiness.
Other experts, however, are less worried. "Nothing happened in the trials that made [Belsomra] look safer or more dangerous than other sleeping pills," Dr. Thomas Roth, a sleep medicine expert who has consulted for pharmaceutical companies including Merck, told HuffPost in an email.
Belsomra's safety profile "maintains the same precautions and warnings as other sleep medications on the market," Merck Global Director of Communications Megan Wilkinson said.
Regardless, many doctors recommend exhausting all other options for treating insomnia before turning to medication.
"When someone has insomnia -- a long-term sleep difficulty associated with daytime impairment -- the first steps are to look into good sleep practices," Roth said.