On prescribing and medicines management

'Our study found that typically 130 unique medications account for 90% of the prescribing volume of GP practices in England, and variation, which was primarily between practices, was relatively low. The mean DU90% of 130 per GP practice in this study is similar to previous studies which reported means ranging from 128 to 165 drugs in practices’ DU90%, and variation similarly in the range of two fold'

The drug utilisation 90% (DU90%) is a measure recommended by the WHO for drug utilisation research, and represents the number of unique drugs which makes up 90% of a doctor’s prescribing.

Doctors can develop expertise in only a certain number of drugs, and so may have to consult information sources when considering others they are less familiar with. For this reason, the WHO’s Guide to Good Prescribing suggests that prescribers should develop a personal list (ie, drugs they have chosen to prescribe regularly which they are familiar with that are their priority option for given indications)

Use of a relatively limited number of core drugs, which a prescriber is an expert in, may reduce task complexity in treatment decisions and potentially be associated with a higher quality of prescribing and reduced errors.7 8 The availability of many alternatives with similar therapeutic effects can compromise patient safety through potential confusion between drugs within a class but with different properties or dosage.9 Mitigating this risk of confusion is one basis for developing a core drug list for undergraduate and postgraduate prescribing education in the UK.10 11 Some countries have implemented restricted formularies or essential medicines lists on this basis, such as the ‘Wise List’ in Sweden and local formularies in the UK,9 12 13 to help facilitate clinicians in prescribing the most effective, safe and appropriate medications for their patients.14