Characteristics of demand for antibiotics in primary care: an almost ideal demand system approach

We model demand for different classes of antibiotics used for respiratory infections in outpatient care using a linear approximate almost ideal demand system approach. We compute elasticities to socioeconomic determinants of consumption and own- and cross- price elasticities between different groups of antibiotics. We find significant elasticities between newer/more expensive generations and older/less expensive generations of antibiotics. The larger use of more expensive antibiotics is also associated with the self-dispensing status of practices, ceteris paribus.