Computerised advice on drug dosage to improve prescribing practice

Maintaining therapeutic concentrations of toxic drugs is a complex task. Several computer systems have been designed to help doctors determine optimum drug dosage. Significant improvements in health could be achieved if computer advice was shown to be beneficial.

To assess whether computer support for drug dosage benefits patients and hence whether it should be more widely available.

We searched the Cochrane Effective Practice and Organisation of Care Group specialised register (June 1996), MEDLINE (1966 to June 1996), EMBASE (1980 to June 1996), hand searched the journal Therapeutic Drug Monitoring (1979 to June 1996), reference lists of articles and contacted experts in the field.

Randomised trials, interrupted time series and controlled before and after studies of computerised advice on drug dosage. The participants were health professionals responsible for patient care. The outcomes were: any objectively measured change in the behaviour of the health care provider (such as changes in the dose of drug used); any change in the health of patients, resulting from computer support (such as adverse reactions to drugs).

Two reviewers independently extracted data and assessed study quality.

Fifteen trials involving 1229 patients were included. The drugs studied were theophylline, warfarin, heparin, aminoglycosides, nitroprusside, lignocaine, oxytocin, fentanyl and midazolam. Interventions usually targeted doctors although some studies attempted to influence prescribing by pharmacists and nurses. All included studies took place on acute medical conditions in hospital settings. Although all studies used reliable outcome measures, sample size was often small and only two studies reported a sample size calculation. Computer support for drug dosage gave significant benefits reducing: 1. The time to achieve therapeutic control (standardised mean difference -0.44, 95% CI -0.70 to -0.17); 2. Toxic drug levels (risk difference -0.12, 95% CI -0.24 to -0.01); 3. Adverse reactions (risk difference -0.06, 95% CI -0.12 to 0.00); 4. Length of hospital stay (standardised mean difference -0.32, 95% CI -0.60 to -0.04). There was a tendency for computer support to result in higher doses of drugs, although this did not reach statistical significance.

This systematic review provides evidence to support the use of computer assistance in determining drug dosage. Further clinical trials are necessary to determine whether the benefits seen in specialist applications can be realised in general use.