What you need to know about the latest sleeping pill

A controversial sleeping pill that suppresses orexin, a key chemical promoting wakefulness, is now available on the private market in Australia.

Suvorexant (Belsomra) is the first in a new class of drugs known as orexin-receptor antagonists and is indicated for treatment of insomnia that is characterised by difficulties with sleep onset and/or maintenance.

The TGA failed to approve suvorexant in 2015, citing efficacy and safety concerns, including suicidality, abnormal sleep behaviours and next-day drowsiness affecting the ability to drive.

In clinical studies, the drug has been shown to be more effective than placebo for sleep onset and maintenance, enhancing overall sleep time by 45 minutes on first use.

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The most common side effect reported by participants is next-day somnolence.

Suvorexant will be available at the recommended dose of 20mg once-nightly for adults under 65 and 15mg for those over 65. A pack of 30 tablets will cost about $60.

Dr David Cunnington, from Melbourne’s Sleep Disorder Centre, says that unlike benzodiazepines, addiction is not an issue for suvorexant as the drug does not enhance GABA to induce sedation.

“[But] it is important that GPs and pharmacists explain to patients prescribed Belsomra that the therapy may feel different to other sleep medications,” says Dr Cunnington, who has been an adviser to the drug's manufacturer, MSD.

CBT should always be first-line treatment for patients with insomnia, says Associate Professor Garun Hamilton, clinical chair of the Australasian Sleep Association and a Monash University sleep researcher previously involved with suvorexant trials but with no current conflict of interest.

Doctors could consider combining CBT with sleeping medication cautiously and only for some patients, he adds.

“Because this drug is new and we haven’t really used it yet outside of clinical trials, we’re still going to need to find its place and see exactly who it’s going to work best in, in real-world clinical practice."

Dr Hamilton recommends GPs consider prescribing the medication with an end point in mind, while also being mindful that insomnia often coexists with other problems, particularly anxiety and depression.

“The trouble with clinical trials is they exclude people with major depression,” he notes.

Suvorexant may benefit people with a very strong waking drive in which CBT alone has not worked because it may work on the underlying mechanism of insomnia, he says.

“It certainly does have a potential advantage over standard hypnotics because usually in insomnia the key mechanism that’s disordered is the wake-promoting system in the brain, which is too active and the person can’t switch their brain off."