===== Defined Daily Dose for human medication statistics (DDD) =====


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.\\ \\
Only one DDD is assigned per ATC code and route of administration (e.g. oral formulation).  The DDD is nearly always a compromise based on a review of available information including doses used in various countries when this information is available.  The DDD is sometimes a “dose” that is rarely if ever prescribed, because it might be an average of two or more commonly used doses. 

The unit of Defined Daily dose for humans is milligrams per human adult per day (mg*homo*day).  The concept of "homo" refers to an adult human weihging 70 kg. Consequently, the World Health Organization’s guidelines for ATC classification and DDD assignment in humans states that DDDs in children ages >1 month to 18 years are impossible to assign, as pediatric doses are dependent on age and weight, which vary widely
         
For animals it is recommended to use "DDDvet" (VETERINARIUS meaning animals).  Obviously, in animals, we cannot ignore the variability in animal weight during the growth period and the large difference of weights between breeds (ex: dogs) and claim that all antibiotics are used on an adult animals with one standradized weight.  Consequently, the unit of Defined Daily dose for animals is defined  in milligrams per kg  per day (mg/kg/day).  

Consequently, the use of the acronym “DDD” should be reserved for describing the use of drugs intended for humans and should not be used to report "Defined daily doses" for animals.

More details on DDDs in the following website [[https://www.whocc.no/ | (ATC and DDD an international language for drug utilization research) ]]