Suvorexant Prescription-Record Rates After a Palliative Care Pocket Manual Revision: A Single-Centre Interrupted Time Series Study.

To examine whether a palliative care pocket manual revision suggesting suvorexant for nocturnal awakening was associated with changes in suvorexant prescription-record rates. We conducted a single-center retrospective interrupted time series study at a Toyama University Hospital using weekly prescription records for suvorexant (15 mg and 20 mg tablets combined). Prescription records, not unique patients, were analyzed with segmented negative binomial regression using an offset for days per week. The manual was updated on 16 May 2025; the first post-implementation week was 19 May 2025. The primary all-hospital series included 105 wk and 3,927 records. The immediate level change was in the direction of increase but statistically uncertain (IRR 1.34, 95% CI 0.88 to 2.05; p = 0.177), with no slope change (IRR per week 1.00, 95% CI 0.98 to 1.02; p = 0.888). Outpatient prescription-record rates showed a modest immediate increase (IRR 1.38, 95% CI 1.01 to 1.90; p = 0.043), whereas inpatient estimates were imprecise. Outpatient sensitivity analyses reduced statistical clarity. This local pharmacotherapy guidance revision coincided mainly with a secondary outpatient prescribing signal. Causality, clinical utility, and patient outcomes cannot be inferred.