Medicines have been used irrationally for as long as they have been available; this reduces quality of care, wastes resources and may cause harm to patients. The first step to improving drug use is to investigate what kinds of problems there are and the extent to which they occur. Unless drug use is investigated, measured and documented, it is impossible to evaluate the effectiveness of interventions to promote rational use. This chapter describes a number of methods or tools to investigate drug use. It is up to the reader to choose the combination of methods most suited to the type of problem to be investigated and the type of data available.

STEP 1 General investigation to identify problem areas

Initial investigation should identify broad areas of inappropriate use of medicines. There are two main ways of doing this:

• Aggregate data methods (section 6.2) use data that are not collected at the individual patient level; such data are often routinely available for purposes other than investigating drug use, for example stock records. Aggregate data give an overview of drug use, which is useful in managing the formulary list.

• Indicator study methods (section 6.3) use data which are collected at the individual patient level, for example prescriptions or patient-provider interactions. Indicator study data are collected specifically to investigate medicine use, but do not include sufficient information to make individual judgements concerning the appropriateness of a drug prescription for an individual diagnosis. Such data can therefore be collected by trained personnel who are not doctors, pharmacists or nurses.

STEP 2 In-depth investigation of specific problems

Once an area of inappropriate medicine use is identified, it should be examined in depth in order to determine the size and nature of the problem and the reasons underlying the problem. Such investigation may include, for example:

• Prescription audit to see if the treatment of a specific disease is in accordance with guidelines (see section 6.3 on the complementary indicator - the percentage of prescribing encounters in accordance with standard treatment guidelines).

• Qualitative methods to determine the causes of a drug use problem (see section 6.4). There may be many rational reasons why people use medicines inappropriately; unless these reasons are understood it is impossible to devise an effective strategy to change behaviour.

• Drug utilization review to see if the use of a specific medicine is in accordance with previously agreed criteria (see section 6.5).

STEP 3 Develop, implement and evaluate strategies to correct the problem

Strategies to promote more rational use of medicines are described in chapter 7. Box 8.3 in section 8.2 describes how the use of injections was investigated in Indonesia and then a strategy developed and implemented to reduce inappropriate use.