New research has reviewed the scientific evidence for medications used to treat insomnia. Lemborexant, a drug that is not yet authorized to be marketed in Brazil, was recognized as the most effective, although there are still no robust data on safety.
The drug is produced by the pharmaceutical company Eisai. Luiz Silva, technical manager for the company’s Brazilian branch, says that the drug is being analyzed by Anvisa (National Health Surveillance Agency). According to him, the expectation is that lemborexant will be approved in the first half of 2023.
If this really happens, “we intend to make the drug available in pharmacies still in the year 2023, probably in the second semester”. For now, the drug has no price estimate. In the US, they have been approved by the FDA (Food and Drug Regulatory Agency) since 2019. In the UK, it has not yet been approved.
The study that reached a favorable conclusion for lemborexant is a systematic review – that is, it considers the scientific evidence from other published articles. Signed by researchers at the University of Oxford, the new article was published in The Lancet in July this year.
Several drugs used to treat insomnia in adults were considered in the research. The objective was to compile the results on the effects that the drugs have in studies that also had a placebo group (when the participant does not take the drug, but without knowing this information).
The authors delimited four factors to analyze drug efficacy: drug efficacy in improving sleep quality, treatment discontinuation rate, side effects, and drug safety.
So, it was possible to compare the remedies and conclude which ones would be better. According to the authors, eszopiclone and lemborexant had the best results. The first, however, had greater side effects.
For Dalva Poyares, neurologist and member of the Brazilian Sleep Association (ABS), the result is not so surprising because the positive effect of the drug was already known.
She explains that the drug has shown good efficacy without causing many side effects among the elderly. This age group typically has adverse reactions to sleeping pills, such as mental confusion, but lemborexant has shown promising results. “Every sleeping pill has some of these issues in the elderly,” she says.
New drug family
Medicines such as lemborexant make up the so-called family of antagonists of hypocretin (or orexin), a substance present in the hypothalamus, a small region of the human brain.
“Hypocretin is involved in several processes in the body. Eating behavior and cardiovascular regulation are two of them. But one of the main functions is wakefulness, keeping the person awake”, he explains.
Under normal conditions, hypocretin has a drop in activity during the night, and when it is close to waking up, the substance begins to act and continues throughout the day.
Thus, researchers imagined that working with hypocretin could be a way to treat insomnia. By decreasing the activity of the substance during the night, this induces the patient to sleep because it is involved with the person’s wakefulness.
“These drugs are called antagonists because they block the action of hypocretin and promote sleep”, explains the neuroscientist.
She also points out that these types of drugs have the advantage of decreasing the chance of addiction. “The probability is almost nil.”
In addition to lemborexant, other drugs in this family of drugs already exist. The first of these was almorexant. The drug, however, was not approved for use because it showed liver toxicity, says Poyares.
Then came suvorexant, the first approved. “He had the problem that if he increased the dose and improved the effect, it would cause a residual effect in the morning (when the person is still sleepy the next day). It hurt him,” he says.
The lemborexant sought to overcome the residual problem – according to Poyares, the drug achieved this feat.
The neuroscientist claims that there is already another newer drug in the family that works with hypocretin: daridorexant. She explains that the results of studies already indicate that the drug is promising, but, because it is very new, it did not enter the newly published review.
it’s not for everyone
If approved in Brazil, the promising results do not indicate that anyone suffering from insomnia should go to the pharmacy to buy lemborexant. “It’s not for 100% of insomnia”, says the neuroscientist.
Poyares explains that a situation in which the remedy may not be the best is when insomnia is associated with another illness, such as depression. In these cases, it may be necessary to adopt medications that also act on the other condition in order to have positive results in sleep.
There is also a consensus that other non-pharmacological measures, such as sleep hygiene techniques, relaxation and cognitive-behavioral therapy, should always be prioritized in the treatment of insomnia.
The new systematic review also concluded that, although lemborexant had the best results and demonstrated safety in clinical studies, these latest data are still not very robust.
In Poyares’ view, this is due to the fact that the drug has not yet been on the market for a long time. Therefore, pharmacovigilance data (when users report situations with the drug) are scarce.
“Let’s say that in five years there will be four reports of people who started to eat at night. This can happen”, exemplifies the neuroscientist.
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