Administration of Pro Re Nata Medication: A Retrospective Quantitative Study in Mental Health Acute Care Inpatient Units

Pro re nata medication use in inpatient mental health services is frequent and may not be as effective as regularly administered medications. Previous studies usually only include specific pro re nata medication types, such as antipsychotics or sedatives, which account for a relatively small proportion of all pro re nata medications. This study aimed to provide a comprehensive overview of the frequency of pro re nata medication administrations, including the types of medications used. A retrospective cohort study across three acute adult inpatient mental health units was conducted. Medication data were extracted from the clinical information system and linked to clinical coding data. Pro re nata medications were administered in 83% of hospital admissions (n = 2011). The most frequently administered medication categories were benzodiazepines, antipsychotics, analgesics and anti-inflammatories. There was more frequent administration of pro re nata to younger consumers and when regular medication was also administered. This study found that pro re nata medication administration is common in inpatient mental health units and is influenced by multiple factors, including consumer age and medication type. Routine use of pro re nata medication, alongside regular medication, may lead to unsafe combined doses, and indicate untreated mental and physical symptoms.