Defined Daily Doses
Encyclopedia
The defined daily dose is a statistical measure of drug consumption, defined by the World Health Organization
(WHO). It is used to standardize the comparison of drug usage between different drugs or between different health care environments. The DDD is not to be confused with the therapeutic dose or with the dose actually prescribed by a physician for an individual patient.
The WHO's definition is: "The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults."
propranolol are much less effective than 20 mg of the beta blocker bisoprolol
. To reflect this, the WHO has decided on a DDD for propranolol of 160 mg and for bisoprolol of 10 mg. Individual patients can still be prescribed higher or lower doses, for instance in children, patients with liver or kidney impairment, patients with a combination therapy
, or due to differences in drug metabolism
between individuals or ethnicities (genetic polymorphism).
The DDD system is most frequently used in academic articles and reports, and as a tool for comparison and control over nationwide total drug consumption. For example, the overall drug consumption of beta blockers can be measured in DDDs and compared between different countries, sexes or other populations.
For example, the analgesic
(pain reliever) paracetamol
has a DDD of 3 g, which means that an average patient who takes paracetamol for its main indication, which is pain relief, uses 3 grams per day. This is equivalent to six standard tablets of 500 mg each. If a patient consumes 24 such tablets (12 g of paracetamol in total) over a certain span of time, this equals a consumption of four DDDs.
World Health Organization
The World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
(WHO). It is used to standardize the comparison of drug usage between different drugs or between different health care environments. The DDD is not to be confused with the therapeutic dose or with the dose actually prescribed by a physician for an individual patient.
The WHO's definition is: "The DDD is the assumed average maintenance dose per day for a drug used for its main indication in adults."
Use
A common problem when comparing drugs is that different medications can be of different potency. For example, 20 mg of the beta blockerBeta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
propranolol are much less effective than 20 mg of the beta blocker bisoprolol
Bisoprolol
Bisoprolol is a drug belonging to the group of beta blockers, a class of drugs used primarily in cardiovascular diseases. More specifically, it is a selective type β1 adrenergic receptor blocker. The FDA approved Duramed Pharmaceutical's application for Zebeta Oral Tablets as a new molecular...
. To reflect this, the WHO has decided on a DDD for propranolol of 160 mg and for bisoprolol of 10 mg. Individual patients can still be prescribed higher or lower doses, for instance in children, patients with liver or kidney impairment, patients with a combination therapy
Combination therapy
Combination therapy or polytherapy is the use of more than one medication or other therapy. In contrast, monotherapy is any therapy which is taken by itself....
, or due to differences in drug metabolism
Drug metabolism
Drug metabolism is the biochemical modification of pharmaceutical substances by living organisms, usually through specialized enzymatic systems. This is a form of xenobiotic metabolism. Drug metabolism often converts lipophilic chemical compounds into more readily excreted polar products...
between individuals or ethnicities (genetic polymorphism).
The DDD system is most frequently used in academic articles and reports, and as a tool for comparison and control over nationwide total drug consumption. For example, the overall drug consumption of beta blockers can be measured in DDDs and compared between different countries, sexes or other populations.
Calculation
If the DDD for a certain drug is given, the number of DDDs used by an individual patient or (more commonly) by a collective of patients is as follows.For example, the analgesic
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
(pain reliever) paracetamol
Paracetamol
Paracetamol INN , or acetaminophen USAN , is a widely used over-the-counter analgesic and antipyretic . It is commonly used for the relief of headaches and other minor aches and pains and is a major ingredient in numerous cold and flu remedies...
has a DDD of 3 g, which means that an average patient who takes paracetamol for its main indication, which is pain relief, uses 3 grams per day. This is equivalent to six standard tablets of 500 mg each. If a patient consumes 24 such tablets (12 g of paracetamol in total) over a certain span of time, this equals a consumption of four DDDs.
See also
- Anatomical Therapeutic Chemical Classification SystemAnatomical Therapeutic Chemical Classification SystemThe Anatomical Therapeutic Chemical Classification System is used for the classification of drugs. It is controlled by the WHO Collaborating Centre for Drug Statistics Methodology , and was first published in 1976....
- ADQ (average daily quantity), a BritishUnited KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
alternative