Effect of Suvorexant on Nocturnal Delirium in Elderly Patients with Alzheimer's Disease: A Case-series Study

Suvorexant, an orexin receptor antagonist used for insomnia, has been shown to have a preventive effect on delirium in a randomized placebo-controlled trial. However, its effectiveness in the management of nocturnal delirium has not yet been determined. Here we report four cases in which elderly patients with moderate to severe Alzheimer's disease who developed nocturnal delirium were treated with suvorexant. In case 1, 15 mg suvorexant was initiated to manage nocturnal delirium refractory to antipsychotics, antidepressants, and a Japanese herbal medicine, resulting in immediate sleep improvement. However, treatment discontinuation led to recurrence of symptoms, which were reversed by recommencing suvorexant. In case 2, as antipsychotics used for the treatment of nocturnal delirium were ineffective, 15 mg suvorexant was administered. The patient achieved rapid improvement in sleep. In case 3, the use of atypical antipsychotics for the treatment of nocturnal delirium was contraindicated, as the patient had diabetes. Therefore, 15 mg suvorexant was administered following good outcomes in cases 1 and 2, resulting in immediate sleep improvement. Finally, in case 4, 15 mg suvorexant was used as an initial medication for nocturnal delirium, and the patient showed sleep improvement immediately. Elevated orexin levels in the cerebrospinal fluid are reportedly linked to sleep deterioration in patients with moderate to severe Alzheimer's disease. The immediate and reproducible action and effectiveness of suvorexant observed in our patients suggest that enhanced cerebral orexin activity might be associated with sleep-wake cycle disturbances due to delirium in elderly patients with Alzheimer's disease.

Assessment of Switching to Suvorexant versus the Use of Add-on Suvorexant in Combination with Benzodiazepine Receptor Agonists in Insomnia Patients: A Retrospective Study

OBJECTIVE: Suvorexant is a novel hypnotic drug that does not interact with the conventional γ-aminobutyric acid (GABA)-A receptor. We investigated the method by which suvorexant was introduced in insomnia patients who were taking benzodiazepine receptor agonists (BzRA). METHODS: This was a retrospective study. We extracted clinical data for patients who were prescribed suvorexant and were already using BzRA. The patients were assigned to two groups, the switching and add-on groups. We assessed the suvorexant discontinuation rate at one month after the prescription of the drug. RESULTS: One hundred and nineteen patients were assigned to the switching group, and 109 were assigned to the add-on group. The add-on group exhibited a significantly higher all-cause discontinuation rate than the switching group (odds ratio, 2.7; 95% confidence interval, 1.5 to 5.0; adjusted p < 0.001). Intolerability was a significantly stronger risk factor for suvorexant discontinuation in the add-on group (22.0% vs. 7.6%, p < 0.002), and the most common adverse effect was oversedation. CONCLUSION: Our results show that the add-on of suvorexant increases the frequency of oversedation compared with switching in insomnia patients that are taking BzRA. However, this was only a preliminary retrospective study, and further studies will be required to confirm our findings.

Efficacy and safety of suvorexant for the treatment of primary insomnia among Chinese: A 6-month randomized double-blind controlled study

Background: Insomnia often responds to the orexin receptor antagonist suvorexant. This study aimed to evaluate the efficacy and adverse events of suvorexant for Chinese patients with primary insomnia over 6 months. Methods: A total of 120 patients with primary insomnia were assigned randomly to two groups that received placebo or suvorexant (40 mg) for 6 months. The primary outcomes were the total sleep time (sTST), time to sleep onset (sTSO), and sleep quality (sQUAL). The secondary outcomes were the Insomnia Severity Index (ISI) score and adverse events. Results: A total of 111 patients completed the study and all of them were included in the final analysis. Suvorexant showed greater efficacy than the placebo in enhancing sTST, sTSO, sQUAL and ISI score at months 1 and 6. Serious adverse events were documented in 2 patients (3.3%) in the suvorexant group and 1 patients (1.7%) in the placebo group. The most common adverse event was somnolence, which occurred in 7 patients (11.7%) in the suvorexant group and 2 patients (3.3%) in the placebo group. No death related to suvorexant treatment was recorded. Conclusions: Suvorexant was efficacious and well-tolerated in a group of Chinese patients with primary insomnia over 6 months.