Guidelines for ATC classification and DDD assignment - WHOCC

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Diuretics in combination with angiotensin II antagonists are classified in
C09DA.
The need for a systematic approach to classify combinations of different
antihypertensives has resulted in a ranking according to the ATC codes.
Substances classified in ATC group C02AA take precedence over
C02AB and substances in C02A take precedence over C02B etc.
Example: A combined preparation containing bietaserpine, hydralazine
and hydrochlorothiazide will be given the code C02LA07 according to
the above mentioned ranking.
Combinations with psycholeptics are classified at separate 5th levels
using the corresponding 70-series.
It has been considered most appropriate to assign fixed DDDs
based on the average use of the different combinations without
considering and comparing the strengths of the various
components. 1 tablet is the fixed DDD for products given once
daily whereas the fixed DDD for products given twice daily and
three times daily is respectively 2 tablets and 3 tablets. The
assigned DDDs cannot always be compared with the DDDs
assigned for plain preparations.
C02LA Rauwolfia alkaloids and diuretics in combination
C02LB Methyldopa and diuretics in combination
C02LC Imidazoline receptor agonists in combination with diuretics
C02LE Alpha-adrenoreceptor antagonists and diuretics
C02LF Guanidine derivatives and diuretics
C02LG Hydrazinophthalazine derivatives and diuretics
C02LK Alkaloids, excl. rauwolfia, in combination with diuretics
C02LL MAO inhibitors and diuretics
C02LN Serotonin antagonists and diuretics