Concomitant inpatient prescribing of strong opioids with sedatives: Associations with comorbid conditions.

Co-prescribing of opioids and sedatives is a known risk factor for opioid-induced ventilatory impairment (OIVI). Prevalence data for sedative and opioid co-prescription in inpatients in Australia are unknown. Our objective was to determine the prevalence of inpatient sedative and opioid co-prescribing and to identify factors associated with co-prescription. We conducted a retrospective cross-sectional study from July 2017 to October 2017 across four South Australian hospitals utilizing a centralized electronic health record. Multivariate analysis was used to identify characteristics predictive of co-prescribing of a strong opioid (fentanyl, hydromorphone, morphine, and oxycodone) and sedative medications (benzodiazepines, antiepileptics, antipsychotics, and tricyclic antidepressants). Of the 6170 inpatients, 2795 (45.3%) were prescribed a strong opioid and of those, 1889 (30.6% of all inpatients) were co-prescribed a sedative. Of those prescribed a strong opioid, five (0.18%) developed OIVI. Patients prescribed a strong opioid had a 27-77% increased likelihood of being prescribed a sedative. Factors predictive of sedative co-prescribing included the presence of disease of the central nervous system adjusted OR (aOR) 8.66 [95% CI 5.83-12.9] and respiratory disease aOR 1.42 [95% CI 1.17-1.72]. Nearly, one third of all hospital inpatients were co-prescribed a strong opioid and a sedative medication. Patients with comorbidities resulting in increased risk of respiratory depression/OIVI were more likely to have sedative co-prescription. Clinicians should be aware of the effects of high-risk medications and ensure that systems and monitoring are in place that help mitigate adverse outcomes.