Measurement of drug utilization in Sweden: methodological and clinical implications.

The available sources of information on drug utilization in the Swedish population at large are reviewed. They comprise whole-sale statistics, drug deliveries to hospitals and prescription data. Drug consumption is preferably expressed in defined daily doses (DDD) per capita, where DDD is the average recommended dose on the major indication of the drug. Under ideal circumstances--drugs used continuously on one indication--the number of DDDs per population ought to agree with morbidity data. This turned out to be the case with antidiabetic drugs. The pitfalls with this unit of measurement include major discrepancies between recommended and prescribed doses, and the use of the drug on vastly different indications (such as neurosis and psychosis in the case of neuroleptics). Nevertheless, the DDD methodology may serve as a therapeutic audit in attempts to follow and influence therapeutic habits of health personnel in hospitals and primary health care. Wholesale data combined with individual-based prescription data are particularly useful in this regard.