Computer based prescribing

Better accuracy and appropriateness

Tools for computer based prescribing range from existing general practice systems, such as those for repeat prescribing, through computerised textbooks such as the new electronic British National Formulary, to decision support tools that extract data from the patient's record and suggest a ranked list of suitable drugs.9 These more sophisticated decision support tools can improve the accuracy, appropriateness, speed, and cost of prescribing. Evidence from three randomised studies showed that use of decision support tools improved the accuracy of drug dosing,10 while ward pharmacists who used decision support tools in an American hospital made better choices of which antibiotic to prescribe.11 British studies showed that using a computer for repeat prescribing saved just over a minute of medical time per prescription and led to 38% fewer phoned requests from patients and 5% fewer inquiries from pharmacists.12 Cost savings of up to 30% were also documented.13

Computer tools have been associated with an 8% increase in generic prescribing14 and make prescriptions more legible and complete; prescribing data on “free” general practice computer systems were 95% complete, whereas handwritten notes were 42% complete.15 A randomised trial is in progress to assess the effects of an advanced decision support tool on the prescribing patterns among British general practitioners [RW, Proceedings of the annual conference of the British Computer Society Primary Health Care Specialist Group, 1993.] Preliminary findings suggest that the prescribing behaviour of general practitioners using the system is closer to that of expert doctors in that they select a higher proportion of appropriate, generic, and cost effective drugs.

Computer based tools assist prescribing in various ways, including by increasing legibility and routinely checking for potential interactions. Some general practitioners, however, find these checks overinclusive or too slow (even a 10 second delay is too long during a consultation16) and turn them off. Prescribing tools can also calculate the appropriate dose and suggest a suitable preparation; a systematic review of drug dose calculators is under way. To work effectively these decision support tools need a computerised list of patients' problems, allergies, and past drug treatment; the legalisation of paperless general practitioner records next April should mean that more doctors keep these data on computer. Preferential prescribing of certain drugs simply because they appear higher on a computer generated list is a potential hazard (G Hayes, personal communication), so lists should be ranked in order of each drug's likely effectiveness for the patient's condition.

Prescribing systems must include a complete, contemporary list of preparations; maintain an accurate prescribing record for every patient (this is invaluable when the government pronounces on the risks of certain drugs, as recently with the newer oral contraceptive pills); and must print out the prescription for the doctor to sign,17 as electronic signatures are not yet legal. Hospital clinicians may be put off using these tools by insufficient space in clinic rooms, lack of funds to install computer workstations at every bedside, and previous experience with inadequate systems.

Several new developments are promised that should improve current systems. Full integration with electronic patient records,16 facilitated by the clinical terms project,18 will provide prescribers with more appropriate lists of drugs and patients with tailored leaflets to improve compliance.19 Once electronic signatures become legal and the NHS-wide network is complete, doctors will be able to send prescriptions electronically to a pharmacy, eliminating signed printouts and speeding follow up inquiries by pharmacists. Perhaps, one day, automated pill counters will even be able to dispense some drugs directly.

The new electronic British National Formulary contains the full text of the paper version with a more detailed seven level hierarchical table of contents and direct links from each drug's entry to its interactions. This is a landmark in the struggle to make prescribing more “evidence based,” but its full potential will be realised only when the information is available in a more structured form for use with the new generation of decision support systems. The compilers of the British National Formulary have begun the enormous task of structuring our knowledge about drugs for use with computers. This important task is central to the next generation of decision support systems for prescribing, which will keep doctors and patients informed and help the NHS to manage its resources more effectively.