Any bulletin that is intended to change prescribing must be informed by knowledge of what is being prescribed and what the problems are. These problems may range from use of a less than ideal drug because the best drug is unavailable, to overuse of expensive drugs for simple problems. The quality of data available will vary greatly. Some countries have good records of all drug prescriptions, but few collect information about the indications for prescribing.

Where prescription data are collected, it is often the trends in utilisation that are the most interesting to monitor. For example, in many countries the use of selective serotonin re-uptake inhibitors (SSRIs) for depression has increased greatly even though it remains unclear when they should be preferred to older and cheaper antidepressants. Figure 4.1 shows an example from the Italian bulletin Dialogo sui Farmaci, which has access to drug utilisation data, showing the growth in use of atypical antipsychotic drugs in recent years.

Changes in prescribing can signal problems, as may reports of adverse drug reactions or interactions. It may also be possible to discover what proportion of hospital admissions are due to problems with medication, for example overdose or failure to take necessary drugs.

Laboratory data can also be useful, for example an increase in resistant bacteria may imply the over use of broad-spectrum antibiotics.

Assuming patients have access to necessary medicines, various utilisation problems may be encountered:

• using a drug with no therapeutic effect, e.g. most tonics;

• prescribing a drug when it is not indicated (and its use is pointless, e.g. it is not effective);

• prescribing a drug which does not cure a condition that should be cured, e.g. prescribing an anti-ulcer drug instead of eradicating Helicobacter pylori;

• using an expensive drug when a cheaper one is equally effective;

• using a drug which is more potent than necessary;

• using drugs for longer than needed or at higher doses than necessary, e.g. non-steroidal anti-inflammatory drugs;

• not using drugs for long enough, e.g. chemotherapy of tuberculosis;

• using too low or too high a dose;

• patients misunderstanding the best way to use their medicines.

Figure 4.1. Change in use of typical and atypical antipsychotic drugs (expressed as Defined Daily Dose DDD/1000 inhabitants/day) in Italy

Source: Dialogo sui Farmaci, Italy.