Re: ATC/DDD- what we learnt at WHO TBS

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Hello all, This is really very interesting topic as ATC/DDD holds very important position for drug utilization researchers. The field of drug utilization research has attracted increasing interest since its infancy in the 1960s. At a symposium in Oslo in 1969 entitled The Consumption of Drugs, it was agreed that an internationally accepted classification system for drug consumption studies was needed. By modifying and extending the European Pharmaceutical Market Research Association (EPhMRA) classification system, Norwegian researchers developed a system known as the Anatomical Therapeutic

Chemical (ATC) classification. In order to measure drug use, it is important to have both a classification system and a unit of measurement. To deal with the objections against traditional units of measurement, a technical unit of measurement called the Defined Daily Dose (DDD) to be used in drug utilisation studies was developed. The NLN (The Nordic Council on Medicines) published the Nordic Statistics on Medicines using the ATC/DDD methodology for the first time in 1976. Since then the interest in the ATC/DDD system for drug utilisation research has expanded. In 1981, the WHO Regional Office for Europe recommended the ATC/DDD system for international

drug utilization studies. In 1996, WHO recognised the need to develop use of the ATC/DDD system as an international standard for drug utilization studies. When the decision on globalizing the ATC/DDD system was taken, the WHO Division of Drug Management and Policies established the WHO International Working Group for Drug Statistics Methodology The purpose of the ATC/DDD system The purpose of the ATC/DDD system is

to serve as a tool for drug utilization research in order to improve quality of drug use The ATC classification – structure and principles Drugs are classified in groups at five different levels. The drugs are divided into fourteen main groups (1st level), with one pharmacological/therapeutic subgroup (2nd level). The 3rd and 4th levels are chemical/pharmacological/therapeutic subgroups and the 5th level is the chemical substance. The 2nd, 3rd and 4th levels are often used to identify pharmacological subgroups when that is considered more appropriate than therapeutic or chemical

subgroups. Principles for classification Medicinal products are classified according to the main therapeutic use of the main active ingredient, on the basic principle of only one ATC code for each pharmaceutical formulation (i.e. similar ingredients, strength and pharmaceutical form).A medicinal product can be given more than one ATC code if it is available in two or more strengths or formulations with clearly different therapeutic uses. A medicinal product may be used for two or more equally important indications, and the main therapeutic use of a drug may differ from one country to

another. This will often give several classification alternatives. Such drugs are usually only given one code, the main indication being decided on the basis of the available literature. Problems are discussed in the WHO International Working Group for Drug Statistics Methodology where the final classification is decided. Cross-references will be given in the guidelines to indicate the various uses of such drugs.The ATC system is not strictly a therapeutic classification system. At all ATC levels, ATC codes can be assigned according to the pharmacology of the product. Subdivision on the mechanism of action will, however, often be rather broad, since a too detailed classification according to mode of action often will result in having one substance per subgroup which as far as possible is avoided. Some ATC groups are subdivided in both chemical and pharmacological groups. If a new substance fits in both a chemical and pharmacological 4th level, the pharmacological

group should normally be chosen. Other ATC classification systems 1) ATCvet classification 2) ATC herbal classification This is about Anatomical therapeutic chemical classification. Regards Dr. sarang kunda gharpure <gharpurekunda@...> wrote: Hello All, The Anatomical Therapeutic Chemical classification and defined daily dose assignment (ATC/DDD) is a system wherein the medicines are divided into different groups according to the organ / system, on which they act, and their chemical, pharmacological and therapeutic properties. DDD is the assumed average maintenance dose per day for a medicine used for its main indication in adults. It is a tool for presenting drug utilization statistics with the aim of improving drug use. This system has been demonstrated to be suitable

for--- 1. National and international comparisons of drugs. 2. Evaluation of long term trends across nations 3. Assessing the impact of certain events on drug use. 4. Providing data in investigations of drug safety. The drug utilization research group (DURG) was established in 1969.It was given the task of development of internationally applicable method for drug utilization research. Subsequently the ATC/DDD system was developed and used for the first time in 1976.(Main contribution is of Norwegian

researchers) This post appears like class room teaching. But now I would like you to share with me your opinions on the use and misuse of this system and the limitations of using ATC/DDD method. kunda Get the freedom to save as many mails as you wish. Click here to know how.

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[Guest guest]

Hi,

The need exists for a uniform global classification for medicines so

that international comparisons become relevant and meaningful.The

quantum calculations will subserve the utilization studies when the

DDD is considered. Even though these were suggested by WHO decades

back, these did not gain popularity because of the different

national " priorities " and " considerations " over international one.

Hence the ATC and DDD are being re-emphasised.

Vijay Thawani

>

> Hello All,

>

> The Anatomical Therapeutic Chemical classification and defined

daily dose assignment (ATC/DDD) is a system wherein the medicines are

divided into different groups according to the organ / system, on

which they act, and their chemical, pharmacological and therapeutic

properties. DDD is the assumed average maintenance dose per day for a

medicine used for its main indication in adults.

> It is a tool for presenting drug utilization statistics with the

aim of improving drug use.

> This system has been demonstrated to be suitable for---

> 1. National and international comparisons of drugs.

> 2. Evaluation of long term trends across nations

> 3. Assessing the impact of certain events on drug use.

> 4. Providing data in investigations of drug safety.

> The drug utilization research group (DURG) was established in

1969.It was given the task of development of internationally

applicable method for drug utilization research.

> Subsequently the ATC/DDD system was developed and used for the

first time in 1976.(Main contribution is of Norwegian researchers)

>

> This post appears like class room teaching. But now I would like

you to share with me your opinions on the use and misuse of this

system and the limitations of using ATC/DDD method.

> kunda

>

>

>

> ---------------------------------

> Get the freedom to save as many mails as you wish. Click here to

know how.

>

[Guest guest]

Hi Sarang,

Good work in helping the moderator Kunda in taking the topic ahead.

Keep up.

Vijay

> Hello All,

>

> The Anatomical Therapeutic Chemical classification and defined

daily dose assignment (ATC/DDD) is a system wherein the medicines are

divided into different groups according to the organ / system, on

which they act, and their chemical, pharmacological and therapeutic

properties. DDD is the assumed average maintenance dose per day for a

medicine used for its main indication in adults.

> It is a tool for presenting drug utilization statistics with the

aim of improving drug use.

> This system has been demonstrated to be suitable for---

> 1. National and international comparisons of drugs.

> 2. Evaluation of long term trends across nations

> 3. Assessing the impact of certain events on drug use.

> 4. Providing data in investigations of drug safety.

> The drug utilization research group (DURG) was established in

1969.It was given the task of development of internationally

applicable method for drug utilization research.

> Subsequently the ATC/DDD system was developed and used for the

first time in 1976.(Main contribution is of Norwegian researchers)

>

> This post appears like class room teaching. But now I would like

you to share with me your opinions on the use and misuse of this

system and the limitations of using ATC/DDD method.

> kunda

>

>

> ---------------------------------

> Get the freedom to save as many mails as you wish. Click here to

know how.

>

>

>

>

> ---------------------------------

> Be a better friend, newshound, and know-it-all with Mobile.

Try it now.

>

[Guest guest]

Thanks Sarang for the details . I will be back with more relevant information.

kunda

Hello All,

The Anatomical Therapeutic Chemical classification and defined daily dose assignment (ATC/DDD) is a system wherein the medicines are divided into different groups according to the organ / system, on which they act, and their chemical, pharmacological and therapeutic properties. DDD is the assumed average maintenance dose per day for a medicine used for its main indication in adults.

It is a tool for presenting drug utilization statistics with the aim of improving drug use.

This system has been demonstrated to be suitable for---

1. National and international comparisons of drugs.

2. Evaluation of long term trends across nations

3. Assessing the impact of certain events on drug use.

4. Providing data in investigations of drug safety.

The drug utilization research group (DURG) was established in 1969.It was given the task of development of internationally applicable method for drug utilization research.

Subsequently the ATC/DDD system was developed and used for the first time in 1976.(Main contribution is of Norwegian researchers)

This post appears like class room teaching. But now I would like you to share with me your opinions on the use and misuse of this system and the limitations of using ATC/DDD method.

kunda

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[Guest guest]

Dear madam, The limitations could be finding ATC for newly marketed drugs, for off-label use of drugs, drugs with many indications... Our Netrum friends, I am sure will find some more limitations. The use looks simpler than misusing this classification! Anupama. kunda gharpure <gharpurekunda@...> wrote: Hello All, The Anatomical Therapeutic Chemical classification and defined daily dose assignment (ATC/DDD) is a system wherein the medicines are divided into different groups according to the organ / system, on which they act, and their chemical, pharmacological and therapeutic properties. DDD is the assumed average maintenance dose per day for a medicine used for its main indication in adults. It is a tool for presenting drug utilization statistics with the aim of improving drug use. This system has been demonstrated to be suitable for--- 1. National and international comparisons of drugs. 2. Evaluation of long term trends across nations 3. Assessing the impact of certain events on drug use. 4. Providing data in investigations of drug safety. The drug utilization research group (DURG) was established in 1969.It was given the task of development of internationally applicable method for drug utilization research. Subsequently the ATC/DDD system was developed and used for the first time in 1976.(Main contribution is of Norwegian researchers) This post appears like class room teaching. But now I would like you to share with me your opinions on the use and misuse of this system and the limitations of using ATC/DDD method. kunda Get the freedom to save as many mails as you wish. Click here to know how.

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[Guest guest]

Dear Anupama

what you have indicated as limitations of assigning ATC codes is actually done by the WHO International Working Group for Drug Statistics Methodology.An application is to be sent to the group for inclusion of a new drug/new use/new dose/new formulation. The application can be downloaded from their site www.whocc.no

kunda

Hello All,

The Anatomical Therapeutic Chemical classification and defined daily dose assignment (ATC/DDD) is a system wherein the medicines are divided into different groups according to the organ / system, on which they act, and their chemical, pharmacological and therapeutic properties. DDD is the assumed average maintenance dose per day for a medicine used for its main indication in adults.

It is a tool for presenting drug utilization statistics with the aim of improving drug use.

This system has been demonstrated to be suitable for---

1. National and international comparisons of drugs.

2. Evaluation of long term trends across nations

3. Assessing the impact of certain events on drug use.

4. Providing data in investigations of drug safety.

The drug utilization research group (DURG) was established in 1969.It was given the task of development of internationally applicable method for drug utilization research.

Subsequently the ATC/DDD system was developed and used for the first time in 1976.(Main contribution is of Norwegian researchers)

This post appears like class room teaching. But now I would like you to share with me your opinions on the use and misuse of this system and the limitations of using ATC/DDD method.

kunda

Get the freedom to save as many mails as you wish. Click here to know how.

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[Guest guest]

Hello all, Here are principles of DDD asignments.... Principles for DDD assignment DDDs for plain substances are normally based on monotherapy. Exceptions to this rule are given in the guidelines.A DDD will normally not be assigned for a substance before a product is approved and marketed in at least one country.The assigned DDD is based on the following principles: The average adult dose used for the main

indication as reflected by the ATC code. When the recommended dose refers to body weight, an adult is considered to be a person of 70 kg. It should be emphasised that even special pharmaceutical forms mainly intended for children (e.g. mixtures, suppositories) are assigned the DDD used for adults. Exceptions are made for some preparations mainly used by children, e.g. growth hormones and fluoride tablets. The maintenance dose is usually preferred when establishing the DDD. Some drugs are used in different initial doses but this is not reflected in the DDD. The treatment dose is

generally used. If, however, prophylaxis is the main indication, this dose is used, e.g. for fluoride tablets (A01AA01) and some antimalarials. A DDD is usually established according to the declared content (strength) of the product. Various salts of a substance are usually not given different DDDs. Exceptions are described in the guidelines for the different ATC groups. The DDD is nearly always a compromise based on a review of the available information including doses used in various countries when this information is available. The DDD is sometimes a dose that is rarely if ever prescribed, because it is an average of two or more commonly used dose

sizes. Combination products The DDDs assigned for combination products are based on the main principle of counting the combination as one daily dose, regardless of the number of active ingredients included in the combination. If a treatment schedule for a patient includes e.g. two single ingredient products, then the consumption will be measured by counting the DDDs of each single ingredient product separately. If , however, a treatment schedule includes a combination product containing two active ingredients, then the calculated consumption measured in DDDs will normally be lower since the DDD for the combination will be counted. Example I: Treatment with two products, each containing one active ingredient: Product A: Tablets containing 20 mg of substance X (DDD = 20 mg) Product B: Tablets containing 25 mg of substance Y (DDD = 25 mg) The dosing schedule 1 tablet of A plus 1 tablet of B daily will be calculated as a consumption of 2 DDDs. Example II: Treatment with a combination product containing two active ingredients: Products C: Tablets containing 20 mg of substance X and 12.5 mg of substance Y. The DDD of the combination products is assigned as 1 UD = 1 tablet. The dosing schedule 1 tablet of C daily will be calculated as 1 DDD (even though it will be equivalent to 1.5 DDD of the single active ingredients). The following principles for assigning DDDs to combination products apply: For combination products (other than the combination products used in hypertension, see point 2 below) where the ATC code identifies the main ingredient (i.e. for the 50- and 70-series combinations and for some 4th levels combinations), the DDD for the combination product should be equal to the DDD for the main active ingredient. For combination products used for treatment of hypertension (i.e. ATC group C02L, C02N, C03E, C07b-f, C08 and C09), DDDs are based on the average number of dosing intervals per day. This means that: 1 tablet is the DDD for combinations given once daily, whereas 2 tablets is the DDD for combinations given

twice daily and 3 tablets is the DDD for combinations given three times daily etc. This principle means that the assigned DDDs may differ from the DDD assigned for the main active ingredient (according to ATC code). In some ATC groups, it has been decided to use fixed DDDs for all combination products given in e.g. number of tablets regardless of strength. These rules are clearly stated in the chapters of each ATC main group in this publication (e.g. ATC group A02AD, A02BD and A02BX). For all combination products where a DDD assigned deviates from the two rules given above, a list

of these DDDs are available from the Centre and on this website Principles for reviewing and changing DDDs. As the dosages used may change over time, it will always be necessary to make some alterations. The International Working Group for Drug Statistics Methodolgoy may review a DDD whenever the Group finds it appropriate.Changes of DDDs should be kept to a minimum and avoided as far as possible. Too many alterations will always be disadvantageous for long-term studies on drug utilization. Before alterations are made, difficulties arising for the users are weighed against the benefits achieved by the alteration. The same principles used to assign new DDDs also apply when DDDs are reviewed. Changes are generally not made unless they are at least of the order of 50%. This rule is not used for the three-year revision of DDDs, where smaller alterations are allowed. Further, minor alterations are allowed for important drugs, which are frequently used. DDD review after three years All newly assigned DDDs are reviewed during the third year after inclusion in the ATC index with DDDs. The DDDs are reviewed at the first semi-annual meeting of the WHO International Working Group for Drug Statistics Methodology. Further reviews of DDDs After the first three years period, the DDD normally remains unchanged for at least five years unless the WHO Working Group decides to make a total revision of all DDDs assigned in an ATC group. Proposed changes in DDDs based on new information will always be considered, but only after the three years revision has been performed. Regsrds Dr. sarang

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[Guest guest]

Hello Sarang

based on these principles , you could try to reply to my problems posted earlier.

so I understand that you have got the point.

kunda

From: sarang deshmukh <drsarang2000@...>Subject: Re: ATC/DDD- what we learnt at WHO TBSnetrum Date: Saturday, 5 January, 2008, 5:07 PM

Hello all,

Here are principles of DDD asignments.. ..

Principles for DDD assignment

DDDs for plain substances are normally based on monotherapy. Exceptions to this rule are given in the guidelines.A DDD will normally not be assigned for a substance before a product is approved and marketed in at least one country.The assigned DDD is based on the following principles:

The average adult dose used for the main indication as reflected by the ATC code. When the recommended dose refers to body weight, an adult is considered to be a person of 70 kg. It should be emphasised that even special pharmaceutical forms mainly intended for children (e.g. mixtures, suppositories) are assigned the DDD used for adults. Exceptions are made for some preparations mainly used by children, e.g. growth hormones and fluoride tablets.

The maintenance dose is usually preferred when establishing the DDD. Some drugs are used in different initial doses but this is not reflected in the DDD.

The treatment dose is generally used. If, however, prophylaxis is the main indication, this dose is used, e.g. for fluoride tablets (A01AA01) and some antimalarials.

A DDD is usually established according to the declared content (strength) of the product.. Various salts of a substance are usually not given different DDDs. Exceptions are described in the guidelines for the different ATC groups.

The DDD is nearly always a compromise based on a review of the available information including doses used in various countries when this information is available. The DDD is sometimes a dose that is rarely if ever prescribed, because it is an average of two or more commonly used dose sizes.

Combination products

The DDDs assigned for combination products are based on the main principle of counting the combination as one daily dose, regardless of the number of active ingredients included in the combination. If a treatment schedule for a patient includes e.g. two single ingredient products, then the consumption will be measured by counting the DDDs of each single ingredient product separately. If , however, a treatment schedule includes a combination product containing two active ingredients, then the calculated consumption measured in DDDs will normally be lower since the DDD for the combination will be counted.

Example I:

Treatment with two products, each containing one active ingredient:

Product A: Tablets containing 20 mg of substance X (DDD = 20 mg)

Product B: Tablets containing 25 mg of substance Y (DDD = 25 mg)

The dosing schedule 1 tablet of A plus 1 tablet of B daily will be calculated as a consumption of 2 DDDs.

Example II:

Treatment with a combination product containing two active ingredients:

Products C: Tablets containing 20 mg of substance X and 12.5 mg of substance Y. The DDD of the combination products is assigned as 1 UD = 1 tablet.

The dosing schedule 1 tablet of C daily will be calculated as 1 DDD (even though it will be equivalent to 1.5 DDD of the single active ingredients) .

The following principles for assigning DDDs to combination products apply:

For combination products (other than the combination products used in hypertension, see point 2 below) where the ATC code identifies the main ingredient (i.e. for the 50- and 70-series combinations and for some 4th levels combinations) , the DDD for the combination product should be equal to the DDD for the main active ingredient.

For combination products used for treatment of hypertension (i.e. ATC group C02L, C02N, C03E, C07b-f, C08 and C09), DDDs are based on the average number of dosing intervals per day. This means that: 1 tablet is the DDD for combinations given once daily, whereas 2 tablets is the DDD for combinations given twice daily and 3 tablets is the DDD for combinations given three times daily etc. This principle means that the assigned DDDs may differ from the DDD assigned for the main active ingredient (according to ATC code).

In some ATC groups, it has been decided to use fixed DDDs for all combination products given in e.g. number of tablets regardless of strength. These rules are clearly stated in the chapters of each ATC main group in this publication (e.g. ATC group A02AD, A02BD and A02BX).

For all combination products where a DDD assigned deviates from the two rules given above, a list of these DDDs are available from the Centre and on this website Principles for reviewing and changing DDDs.

As the dosages used may change over time, it will always be necessary to make some alterations.

The International Working Group for Drug Statistics Methodolgoy may review a DDD whenever the Group finds it appropriate.Changes of DDDs should be kept to a minimum and avoided as far as possible. Too many alterations will always be disadvantageous for long-term studies on drug utilization. Before alterations are made, difficulties arising for the users are weighed against the benefits achieved by the alteration.

The same principles used to assign new DDDs also apply when DDDs are reviewed.

Changes are generally not made unless they are at least of the order of 50%. This rule is not used for the three-year revision of DDDs, where smaller alterations are allowed. Further, minor alterations are allowed for important drugs, which are frequently used.

DDD review after three years

All newly assigned DDDs are reviewed during the third year after inclusion in the ATC index with DDDs.

The DDDs are reviewed at the first semi-annual meeting of the WHO International Working Group for Drug Statistics Methodology.

Further reviews of DDDs

After the first three years period, the DDD normally remains unchanged for at least five years unless the WHO Working Group decides to make a total revision of all DDDs assigned in an ATC group. Proposed changes in DDDs based on new information will always be considered, but only after the three years revision has been performed.

Regsrds

Dr. sarang

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[Guest guest]

Dear Sarang,

Please use standard font size.The smaller size makes it difficult to

read.

Thanks

Vijay

>

> Hello all,

> Here are principles of DDD asignments....

> Principles for DDD assignment DDDs for plain substances are

normally based on monotherapy. Exceptions to this rule are given in

the guidelines.

>

> A DDD will normally not be assigned for a substance before a

product is approved and marketed in at least one country.

>

> The assigned DDD is based on the following principles:

>

> The average adult dose used for the main indication as reflected

by the ATC code. When the recommended dose refers to body weight, an

adult is considered to be a person of 70 kg. It should be emphasised

that even special pharmaceutical forms mainly intended for children

(e.g. mixtures, suppositories) are assigned the DDD used for adults.

Exceptions are made for some preparations mainly used by children,

e.g. growth hormones and fluoride tablets.

> The maintenance dose is usually preferred when establishing the

DDD. Some drugs are used in different initial doses but this is not

reflected in the DDD.

> The treatment dose is generally used. If, however, prophylaxis

is the main indication, this dose is used, e.g. for fluoride tablets

(A01AA01) and some antimalarials.

> A DDD is usually established according to the declared content

(strength) of the product. Various salts of a substance are usually

not given different DDDs. Exceptions are described in the guidelines

for the different ATC groups.

> The DDD is nearly always a compromise based on a review of the

available information including doses used in various countries when

this information is available. The DDD is sometimes a dose that is

rarely if ever prescribed, because it is an average of two or more

commonly used dose sizes.

> Combination products

> The DDDs assigned for combination products are based on the main

principle of counting the combination as one daily dose, regardless

of the number of active ingredients included in the combination. If a

treatment schedule for a patient includes e.g. two single ingredient

products, then the consumption will be measured by counting the DDDs

of each single ingredient product separately. If , however, a

treatment schedule includes a combination product containing two

active ingredients, then the calculated consumption measured in DDDs

will normally be lower since the DDD for the combination will be

counted.

> Example I:

> Treatment with two products, each containing one active

ingredient:

> Product A: Tablets containing 20 mg of substance X (DDD = 20 mg)

> Product B: Tablets containing 25 mg of substance Y (DDD = 25 mg)

> The dosing schedule 1 tablet of A plus 1 tablet of B daily will

be calculated as a consumption of 2 DDDs.

> Example II:

> Treatment with a combination product containing two active

ingredients:

> Products C: Tablets containing 20 mg of substance X and 12.5 mg

of substance Y. The DDD of the combination products is assigned as 1

UD = 1 tablet.

> The dosing schedule 1 tablet of C daily will be calculated as 1

DDD (even though it will be equivalent to 1.5 DDD of the single

active ingredients).

> The following principles for assigning DDDs to combination

products apply:

>

> For combination products (other than the combination products

used in hypertension, see point 2 below) where the ATC code

identifies the main ingredient (i.e. for the 50- and 70-series

combinations and for some 4th levels combinations), the DDD for the

combination product should be equal to the DDD for the main active

ingredient.

> For combination products used for treatment of hypertension

(i.e. ATC group C02L, C02N, C03E, C07b-f, C08 and C09), DDDs are

based on the average number of dosing intervals per day. This means

that: 1 tablet is the DDD for combinations given once daily, whereas

2 tablets is the DDD for combinations given twice daily and 3 tablets

is the DDD for combinations given three times daily etc. This

principle means that the assigned DDDs may differ from the DDD

assigned for the main active ingredient (according to ATC code).

> In some ATC groups, it has been decided to use fixed DDDs for

all combination products given in e.g. number of tablets regardless

of strength. These rules are clearly stated in the chapters of each

ATC main group in this publication (e.g. ATC group A02AD, A02BD and

A02BX).

> For all combination products where a DDD assigned deviates from

the two rules given above, a list of these DDDs are available from

the Centre and on this website Principles for reviewing and changing

DDDs.

> As the dosages used may change over time, it will always be

necessary to make some alterations.

> The International Working Group for Drug Statistics Methodolgoy

may review a DDD whenever the Group finds it appropriate.

>

> Changes of DDDs should be kept to a minimum and avoided as far as

possible. Too many alterations will always be disadvantageous for

long-term studies on drug utilization. Before alterations are made,

difficulties arising for the users are weighed against the benefits

achieved by the alteration.

>

> The same principles used to assign new DDDs also apply when DDDs

are reviewed.

> Changes are generally not made unless they are at least of the

order of 50%. This rule is not used for the three-year revision of

DDDs, where smaller alterations are allowed. Further, minor

alterations are allowed for important drugs, which are frequently

used.

> DDD review after three years All newly assigned DDDs are

reviewed during the third year after inclusion in the ATC index with

DDDs.

> The DDDs are reviewed at the first semi-annual meeting of the WHO

International Working Group for Drug Statistics Methodology.

> Further reviews of DDDs After the first three years period, the

DDD normally remains unchanged for at least five years unless the WHO

Working Group decides to make a total revision of all DDDs assigned

in an ATC group.

>

> Proposed changes in DDDs based on new information will always be

considered, but only after the three years revision has been

performed.

>

> Regsrds

> Dr. sarang

>

>

>

> ---------------------------------

> Never miss a thing. Make your homepage.

>