Computerised advice on drug dosage to improve prescribing practice

  • Review
  • Intervention


  • RT Walton,

  • E Harvey,

  • S Dovey,

  • N Freemantle

Dr Robert Walton, Honorary Senior Clinical Lecturer, University of Oxford Department of Public Health and Primary Care, Imperial Cancer Research Fund General Practice Research Group, Institute of Health Sciences, Old Road, Headington, Oxford, OX3 7LF, UK.



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.

Search strategy

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.

Selection criteria

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).

Data collection and analysis

Two reviewers independently extracted data and assessed study quality.

Main results

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.

Authors' conclusions

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.

Plain language summary

Plain language summary

Computer-assisted drug dosage guidance can improve therapeutic outcomes, leading to reduced costs and more effective patient care

Certain drugs used in the management of acute conditions can have adverse effects if given in high doses. Calculating and administering the optimal amount of such drugs to individual patients is a complicated and time-consuming process for the clinician. Trials have shown that computer-assisted dosage advice can lead to faster and improved control and treatment. Adverse effects and the length of hospital stay were reduced, leading to a cut in costs. In the future, computerised advice on prescribing levels and drug interactions could be effective in other settings, such as primary care.