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'As required' medication regimens for seriously mentally ill people in hospital

  • Review
  • Intervention




Drugs used to treat psychotic illnesses may take weeks to be effective. In the interim, additional 'as required' doses of medication can be used to calm patients in psychiatric wards. The practice is widespread with 20% - 50% of people on acute psychiatric wards receiving at least one 'as required' dose of psychotropic medication during their admission.


To compare the effects of 'as required' medication regimens with regular regimens of medication for the treatment of psychotic symptoms or behavioural disturbance, thought to be secondary to psychotic illness.

Search methods

We searched The Cochrane Schizophrenia Group's register of trials (March 2006).

We updated this search July 2012 and added three new trials to the awaiting classification section.

Selection criteria

We included all relevant randomised control trials involving hospital inpatients with schizophrenia or schizophrenia-like illnesses, comparing any regimen of medication administered for the short term relief of behavioural disturbance, or psychotic symptoms, to be given at the discretion of ward staff ('as required', 'prn') with fixed non-discretionary patterns of drug administration of the same drug(s). This was in addition to regular psychotropic medication for the long-term treatment of schizophrenia or schizophrenia-like illnesses where prescribed.

Data collection and analysis

We independently inspected abstracts, extracted data from the papers and quality assessed the data. For dichotomous data we would have calculated the relative risks (RR), with the 95% confidence intervals (CI) and the number needed to treat statistic (NNT). Analyses would have been conducted on an intention-to-treat basis.

Main results

We did not identify any randomised trials comparing 'as required' medication regimens to regular regimens of the same drug.

Authors' conclusions

There is no evidence from within randomised trials to support this common current practices. Current practice is based on clinical experience and habit rather than high quality evidence.

Note: the three citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.

Plain language summary

'As required' medication regimes for seriously mentally ill people in hospital

Schizophrenia is a mental health problem whose symptoms can cause agitation, aggression and distress to those who have it. The drugs used to treat it are called antipsychotics and usually take several weeks to work. In the interim for people in hospital, medication can be given ‘as required’ (sometimes called 'pro re nata' or prn) and is often used to help them to feel less anxious and/or to reduce disturbed behaviour. It is usually written on the drug chart by the clinician so that the nurses can administer it at their discretion and in the doctor’s absence. Although there are many advantages to this practice, there are also potential disadvantages in that staff on the ward might use medication for individuals who are upset, rather than spending time with them or considering other approaches.

This review attempts to find evidence to find out whether the use of ‘as required’ medication is good clinical practice or not, when compared to the same drug given regularly, for people with a diagnosis of schizophrenia who are in hospital. However the search strategy used only found trials that compared two different drugs both of which were used as required. No trials were found that compared ‘as required’ with regular medication.

Although the practice of using medication as required is common, there is no good evidence whether this is the best way of helping people to be less agitated when comparing it to being given a regular dose of medication. A well designed, conducted and reported randomised trial would help to answer this question.

(Plain language summary prepared for this review by Janey Antoniou of RETHINK, UK