Guidelines for ATC classification and DDD assignment - WHOCC

- Liquid preparations for inhalation:
1 UD equals 1 ml of the preparation.
- Liquid preparations for inhalation in single dose units (unit dose):
1 UD equals 1 unit dose inhal.sol
- Enemas:
1 UD equals 1 enema.
- Plaster for transdermal application:
1 UD equals 1 plaster.
- Vaginal cream:
1 UD equals 1 dose, 1 application.
Route of administration
The route of administration is indicated by the following codes:
Inhal = Inhalation R = Rectal
N = Nasal SL = Sublingual/buccal
O = Oral TD = Transdermal
P = Parenteral V = Vaginal
C. Pediatric DDD
DDDs are normally assigned based on use in adults (see page 22).
For medicinal products approved for use in children, the dose recommendations
will differ based on age and body weight. Many medicinal products used on
children are not even approved for such use, and documentation regarding dose
regimens is not available.
Thus the WHO International Working Group for Drug Statistics Methodology has
concluded that pediatric DDDs are impossible to assign and problems related to
drug utilization research in children cannot be solved by such means.
Estimating prevalence of drug use in children is not possible by using crude sales
data presented in DDDs. Prescribed daily dosages and indications in a pediatric
population should be used if available and compared with the DDD values. If the
pediatric subgroup is difficult to identify, the general DDD should be used as a
measuring tool for overall comparisons.
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