# Slumber’s Duel: The Upstart Orexin Receptor Antagonists Versus the Battle-Hardened Z-Drugs: Systematic Review and Meta-Analysis Unveiling a Tale of Efficacy and Safety of Two Contenders

**Authors:** Asha Devi Dhandapani, Sathyan Soundara Rajan, Gaurav Uppal, Sneh Babhulkar, Betsy Marina Babu

PMC · DOI: 10.1192/bjo.2025.10086 · 2025-06-20

## TL;DR

This study compares two types of sleep medications, finding that orexin receptor antagonists are as effective as Z-drugs but safer, especially for older adults.

## Contribution

A systematic review and meta-analysis comparing the efficacy and safety of orexin receptor antagonists and Z-drugs for insomnia.

## Key findings

- ORAs reduced sleep onset latency more than Z-drugs by 15.3 minutes.
- ORAs showed a lower risk of next-day somnolence, cognitive impairment, and dependency.
- No significant publication bias was found among the studies analyzed.

## Abstract

Aims: 
Primary insomnia, a separate diagnosis that is now included within the newly broader categorization of insomnia, greatly affects the quality of life. This meta-analysis evaluates the efficacy and safety of orexin receptor antagonists (ORAs) and Z-drugs for insomnia in adults.

Pharmacological approaches to the management of insomnia include the use of our own rendition of those generic drugs commonly referred to as ORAs and Z-drugs. Z-drugs are mainly used; nevertheless, doubts as to their long-term security remain. Targeted at orexin receptors, ORAs are novel. This system consolidates knowledge for use in clinical evaluation and management.

Methods: Accordingly, a Cochrane-Central Register of Controlled Trials Database, a Systematic review using the keywords, ORAs, and Z-drugs was conducted. The criteria for patient inclusion involved all adults diagnosed with insomnia. Measurements of the extent of benefits from the interventions were: Total sleep time, sleep onset latency, and adverse effects.

Bias was determined using SRR and overall risk of bias was determined using the ROB 2 tool. This meta-analysis was conducted by applying random effects models.

Results: Six trials showed that ORAs shortened sleep onset latency compared with zolpidem and other Z-drugs (mean difference −15.3 min, 95% CI −22.1 to −8.5). Total sleep time was similar to total time between sleep onset and wake-up in both groups. ORAs demonstrated a superior safety profile, with lower incidence of next-day somnolence (risk ratio: 0).

This was associated with a decreased risk for cognitive impairment at follow up (risk ratio: 0.65, 95% CI: 0.52–0.81) and for dependency (risk ratio: 0.38, 95% CI: 0.25–0.58).

According to the funnel plot analysis there was no significant publication bias that exists within the studies.

Conclusion: They [ORAs] are at least as effective as the Z-drugs in the management of insomnia and are safer in terms of next-day implications and withdrawal especially in elderly patients. These experiments affirm using ORAs as a first-line pharmacological remedy in chronic insomnia in adults.

## Linked entities

- **Chemicals:** zolpidem (PubChem CID 5732)
- **Diseases:** insomnia (MONDO:0013600)

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Source: https://tomesphere.com/paper/PMC12260697