# Difference between revisions of "Defined daily dose"

Defined daily doses (DDDs) are a WHO statistical measure of drug consumption. DDDs are used to standardize the comparative usage of various drugs between themselves or between different health care environments.

• WHO`s definition: The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults
• A common problem when comparing drugs is that different medication can be of different strengths and different potency. Simply comparing 1g of one, with 1mg of another can be confusing, particularly if different countries use different doses. DDDs aims to solve this by relating all drug use to a standardized unit which is analogous to one day's worth
• The DDD system is most frequently used in academic articles and reports, as well as a tool for comparison and control over nationwide total drug consumption. For example the overall drug consumption of e.g. opioids, can be measured in DDDs and compared between different counties and nations.
• The formula for calculating DDDs is as follows.

${\displaystyle Drug\ Usage(DDDs)=\left({\frac {Items\ issued\times Amount\ of\ Drug\ per\ item}{WHO\ DDD\ Measure}}\right)}$

For example, paracetamol has a DDD of 3g, which means that an average patient who takes paracetamol for pain relief (Paracetamol main indication) uses 3 gram per day. This is equivalent to six standard (500mg) tablets. If a patient consumes twenty four (500mg) tablets (i.e. 12g of paracetamol in total) over the space of six days, he can have said to have consumed four DDDs of this drug.

${\displaystyle (12g(totalamountofdrug)/3g(amountofdruginaDDD)=NumberofDDDs}$