Unit of measurement:(defined daily dose, DDD)
The World Health Organization Collaborating Center of Drug Statistics Methodology defined the DDD as the assumed average maintenance dose per day for a drug used in its main indication in adults . It is a theoretical dose, a compromise between the dosage recommendations of various indications, fixed and regularly updated by the WHO. The DDD system measures the quantity of used drugs, independently of the dosage and the package size, which facilitates the comparisons of consumption.
The quantities in grams of antibiotics were converted in DDD and then expressed in DDD per 1000 inhabitants a day. They are recommended by the WHO as the unit of measurement for drug utilization studies in the ambulatory care setting .
Data collection and results
Based on sales data (IMS Health GmbH), the consumption of antibiotics in the Swiss ambulatory care setting was explored in the study of Filippini et al  and compared with the use from the other European countries. The analysis revealed that Switzerland exhibits relatively low levels of consumption among European countries. On a national level, significant differences were observed across cantons and llinguistic regions. A continuous monitoring of antibiotic use should take over the study. Similar data on the general practitioners' prescription had been collected by the group Sentinella (www.sentinella.ch) or in collaboration with the billling office of the Swiss Society of Pharmacy (OFAC, Geneva).
Regularly updated data are currently being revised and will be available for you.
 World Health Organization Collaboration Center for Drug Statistics Methodology. ATC index with DDDs. Oslo : World Health Organization, 2005.
 Dukes MN. Drug utilization studies. Methods and uses. WHO Reg Publ Eur Ser. 1993 ; 45 :1-4.
 Filippini M, Masiero G, Moschetti K. Socioeconomic determinants of regional differences in outpatient antibiotic consumption : evidence from Switzerland. Health Policy. 2006; 78(1) :77-92.