One of the most common types of sleeping pills prescribed to millions around the world could leave people sleeping through smoke alarms, a new study suggests.
In a trial of benzodiazepines – sedative drugs prescribed for insomnia and anxiety – half the participants slept through a fire alarm that was as loud as someone vacuuming next to their bed.
During sleep, the brain continuously processes sensory information, waking us if it detects a threat – but benzodiazepines make us less likely to rouse in response to sensory input, the researchers explained.
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“Benzodiazepines stimulate the widespread brain receptor GABA-A, which makes us sleepy but also suppresses off-target brain areas, including the ‘gatekeeper’ that decides which sensory inputs to process,” senior study author Professor Tomoyuki Kuwaki, of Kagoshima University, Japan, said.
However, a new and improved type of sleeping pill could offer patients another option. Over the last decade, researchers have been developing a new class of hypnotic drugs called dual orexin receptor antagonists (DORAs).
DORAs more selectively target the brain’s sleep/wake pathways, which gives them advantages over benzodiazepines. These include a reduced ‘hangover effect’, with DORAs less likely to affect driving ability the day after use.
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Professor Kuwaki and his team tested the impact of the new drug DORA-22, compared to a benzodiazepine (called Triazolam) and a placebo in mice.
The research, published in the journal Frontiers in Behavioural Neuroscience, found DORA-22 and Triazolam had similar sleep promoting effects, extending the duration of deep sleep by 30-40% compared to the placebo.
However, when presented with a simulated threat (such as the smell of a fox), mice were more likely to wake after they’d been given DORA-22 compared to Triazolam. They also fell back to sleep quickly after the perceived threat subsided.
The researchers have called for further trials of the drug in humans – fingers crossed it’s available soon.