This article aims to explore mental health professionals' common clinical practices associated with the prescription and administration of pro re nata (p.r.n.) psychotropic medication within acute inpatient mental health settings.

A convenience sample of 59 mental health professionals participated in face-to-face semistructured interviews that explored their p.r.n. psychotropic medication practices in acute mental health settings in a large city in the United Kingdom in 2005. Thematic content analysis was carried out.

Mental health professionals identified a number of themes that were associated with their clinical practices. These included a balanced usefulness of p.r.n. psychotropic medications, factors that influenced their decision making and use of p.r.n. as a clinical intervention and widespread variations in clinical practices. These findings have important implications on how p.r.n. psychotropic medications use differs between individuals, professional groups and organizations within acute inpatient mental health settings.