To define the characteristics of general practices with a special clinical interest in
asthma and to estimate the resulting extra prescribing costs, we sent a postal questionnaire to all English practices containing members of the General Practitioners in
Asthma Group. Item and cost comparisons for 24 PACT (prescribing analysis and cost) aggregates were made between practices who had operated an agreed, written management plan for
asthma before 1 April 1990 and all other practices in their respective Family Health Services Authorities. One hundred and sixty-three practices with GPIAG members responded (70%), of which 26 filled the management plan requirement. These 26 practices showed evidence of significantly better
asthma care provision than the remainder of the sample. Their prescribing costs were significantly higher for respiratory drugs (median 37% higher) but lower in other
drug categories. For respiratory drugs, costs were significantly higher for inhaled
adrenoceptor stimulants,
steroid inhalers, large spacers, and peak flow meters, but lower for
cough medicines and systemic
nasal decongestants: the number of items prescribed showed similar patterns. The prescribing costs of practices claiming a special interest in
asthma are likely to show higher respiratory drug costs, but overall prescribing costs showed no increase in the practices studied.