The World Health Organization (WHO) reports the Defined Daily Dose (DDD) for selected drugs that have an Anatomic Therapeutic Chemical (ATC) classification.

Purpose of the DDD: to provide rough insights into how much of a particular drug is used in a population (drug utilization and consumption monitoring)


Limitations of the DDD:

(1) not all drugs have a DDD

(2) not all formulations of a given drug have a DDD. Only one DDD is assigned per ATC code and route of administration.

(3) a given DDD may reflect the average maintenance dose of a drug if several different doses are available

(4) the given DDD may not correlate with the appropriate dose for a patient

(5) assignment of a DDD is not a recommendation for its use


A DDD may not be assigned for a drug used to treat a rare disease with highly individual dosing schedules.

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