Glossarium

Defined daily dose (DDD) is a concept used for monitoring the use of human drugs (HOMO) internationally. The World Health Organization (WHO) offers a drug classification system (ATC) and proposes defined daily doses (DDD) for each drug. The system proposed by WHO was developed for statistical purposes and the proposed daily doses for each drug are based on the average maintenance dose per day for a drug used for its main indication in an adult human with a standardized weight of 70 kg. The concept is very well explained on the website (ATC and DDD, an international language for drug utilization research) .

The daily dose used by the international consortium is a standardized unit of measurement for statistical purposes and does not necessarily reflect the recommended, prescribed or used daily dose. Indeed, the actual therapeutic daily doses (DTQ) for individual patients and groups of patients will often differ from the daily dose proposed by the monitoring system (DDD). Indeed , the used dose will be based and optimized for the characteristics of the individual requiring a treatment (age, weight, physiological status, ethnic differences) and on the doses deemed ideal to ensure the effectiveness of the treatment of the targeted condition. On the other hand, the DDD proposed by the ATC/DDD monitoring system is almost always a compromise based on a review of the available information. The DDD retained by the ATC/DDD consortium is sometimes a “dose” that is rarely, if ever, prescribed, because it may be an average of two or more doses used in different contexts and countries.

The unit of DDD proposed by the ATC/DDD consortium is in milligrams per adult per day (mg*homo*day). The drug use monitoring system proposed by the ATC/DDD consortium excludes drugs used for children and adolescents (aged >1 month to 18 years) because the standardized reference weight (70 kg) and the defined daily doses proposed by the system does not apply.

More details about DDD _70kg on the following website (ATC and DDD, an international language for drug utilization research) .

Experts in monitoring the use of drugs used in animal populations have proposed adapting the concept used in humans to animals. The international system for animals currently offers the nomenclature system similar to that proposed for humans (ATCvet) but does not offer a concept of standardized defined daily dose by species.

In animal populations, experts from various organizations have proposed defined doses for monitoring the use of antibiotics (one drug among others). In animal populations, we cannot ignore the variability in the weight of animals during the growth period and the large difference in weight between breeds of the same species (e.g. dogs) to define a daily dose. Therefore, the unit of daily dose defined for animals is in milligrams per kg per day (mg/kg/day) and is described by the acronym “DDDvet” (vet for VETERINARIUS meaning animals).

Finally, the daily doses defined for monitoring drug use in animals and humans are based on similar theoretical bases, but the reference doses proposed for animals are based on 1 kg of live weight compared to 70 kg for the humans.

Therefore, this glossary uses weight indices to describe the DDDs proposed for humans (DDD _70kg) and those proposed for animals (DDDvet <sub>1kg</sub >). The reader must also retain that the concept of defined daily doses is a concept developed statistical purpose and that these doses are not necessarily considered “judicious” to ensure effective treatment, prevent side effects or prevent unwanted effects such as antibiotic resistance. Adapted from World Health Organisation Collaborative Centre (WHOCC) for drug statistics methodology documentation. —- === Dose: Defined Daily Doses (DDD₇₀ , mg/jour ) === Statistical measure of drug consumption developed by the World Health Organization (WHO) used to standardize the comparative usage of various drugs between themselves or between different healthcare environments independently of cost or drug formulation. CIPARS (2005)

The Defined Daily Dose (DDD) is a concept used in human medicine (HOMO). It is the assumed to be an average maintenance dose per day for a drug used for its main indication in human adults (≈ 70 kg). The DDD is a standardized unit of measurement and does not necessarily reflect the recommended or Prescribed Daily Dose. Therapeutic daily doses for individual patients and patient groups will often differ from the DDD as they will be based on individual characteristics (such as age, weight, ethnic differences, type and severity of disease) and pharmacokinetic considerations. For more details see "DDD for humans" on this wiki). Adapted from World Health Organisation Collaborative Centre (WHOCC) for drug statistics methodology documentation.