Limited Evidence for the Effectiveness of P.R.N. Medications Among Psychiatric Inpatients

Abstract

The use of medications on a p.r.n. basis on psychiatric inpatient wards is common and widespread but without clear evidence of effectiveness. While individual studies have explored the use of p.r.n. medications in patients receiving scheduled psychotropic medications, no systematic review of the effectiveness of this use of p.r.n. medications has been done. A MEDLINE search was performed of all articles published in English between 1966 and November 2008. Studies were included only if they involved psychiatric patients and if they quantitatively explored the effectiveness of p.r.n. medications. Ten retrospective studies were identified that met inclusion criteria. Among the studies involving adult inpatients, estimates of effectiveness, primarily in the management of agitation, were consistently moderately high, averaging approximately 75%. These studies mainly involved use of antipsychotics and benzodiazepines. Lower estimates of about 30% were obtained in studies involving non-adult inpatients who had few psychotic disorders and among whom there was only minimal use of p.r.n. benzodiazepines. The meaning of effectiveness was often unclear across these retrospective studies. It also appears that important outcome measures, such as duration of hospitalization, may not be affected. Administration of p.r.n. medication was also associated with a greater risk of adverse events. Future studies concerning use of p.r.n. medications in psychiatric patients should examine objective ratings of agitation, medication effects, and adverse events.

A study of the prescription and administration of sedative PRN medication to older adults at a secure hospital

“…Srivastava (2009) has pointed out that agitation is a vague and illdefined concept that could be seen to cover a multitude of behaviors. The most common antecedent documented was threatened or actual violence but it is likely that when PRN was used to prevent or manage serious incidents then these would be more likely to be documented in the patient's case notes than when PRN was used in less pressing circumstances or at patient request.…”

A study of the use of sedative PRN medication in patients at a secure hospital

“…Another problem is that there is a lack of scientific evidence for the effectiveness of PRN medication. There have been two systematic reviews of the subject and both of these failed to find good-quality evidence of the efficacy of PRN medication (Chakrabarti, Whicher, Morrison, & Douglas-Hall, 2007;Srivastava, 2009). Neither review identified any randomised controlled trials of PRN medication and Chakrabarti et al (2007) concluded that the current practice of making common use of PRN 'is based on clinical experience and habit rather than high quality evidence'.…”

“…Like Thapa and colleagues, Smith et al (2008) concluded there had been a reduction in unnecessary patient exposure to medication and that the hospitals concerned had become safer places. Patients receiving PRN medication are at increased risk of drug interactions and side effects (Davies et al, 2007;Srivastava, 2009) and those prescribed PRN antipsychotics may thereby be exposed to high-dose antipsychotics and antipsychotic polypharmacy with the associated increase in physical morbidity such as QTc prolongation, extra-pyramidal side effects, sedation, etc. (Milton, Lawton, Smith, & Buckley, 1998;Paton, Barnes, Rose-Cavanagh, Taylor, & Lelliott, 2008).…”

Patient participation in pro re nata medication in psychiatric inpatient settings: An integrative review

“…). The most frequently prescribed PRN medications are hypnotics, anxiolytics, and antipsychotics (Mullen & Drinkwater ; Srivastava ; Wright et al . ).…”