Talk:Australian Drug Categories

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Cite this page: Hill, M.A. (2019, June 24) Embryology Australian Drug Categories. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Australian_Drug_Categories

Australian Drug Evaluation Committee (ADEC) 1963.


Australian Drug Categories 
Legal drugs are classified, usually by each country's appropriate regulatory body, on the safety of drugs during pregnancy. In Australia, the Therapeutic Goods Authority has classes (A, B1, B2, B3, C, D and X) to define their safety. In the USA, drugs are classified by the Food and Drug Administration (FDA) into classes (A, B, C, D, and X) to define their safety. (More? Australian Drug Categories)


  • Pregnancy Category A - Have been taken by a large number of pregnant women and women of childbearing age without an increase in the frequency of malformations or other direct or indirect harmful effects on the fetus having been observed.
  • Pregnancy Category B1 - Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have not shown evidence of an increased occurrence of fetal damage.
  • Pregnancy Category B2 - Have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.
  • Pregnancy Category B3 - Have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.
  • Pregnancy Category C - Have caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be reversible.
  • Pregnancy Category D - Have caused, are suspected to have caused or may be expected to cause, an increased incidence of human fetal malformations or irreversible damage. These drugs may also have adverse pharmacological effects.
  • Pregnancy Category X - Have such a high risk of causing permanent damage to the fetus that they should NOT be used in pregnancy or when there is a possibility of pregnancy.

Abnormal Development - Drugs


Drug Testing

Typical testing of new drug compound today involves a lengthy series of animal and human studies.

Animal studies

Usually tested in at least two mammalian species (rats and guinea pigs) using both single and repeated doses. For determining reproductive effects, tests on both male and female animals with dosing begins 4 weeks prior to mating are conducted to determine effects on fertility in both sexes, on embryogenesis, and on fetal malformation.

Human Clinical trials

Following animal studies to determine dose, efficacy and apparent safety, human studies can commence. Clinical trials are carried out under very strict conditions, set by international regulatory bodies in agreement with the principles espoused in the Declaration of Helsinki. There are four phases to the trials.

  • Phase I trials - are typically conducted in healthy young male volunteers in groups of about 10−20. They are designed to assess how the drug is absorbed, distributed, metabolised and excreted by the body (that is, pharmacokinetics) and to establish the safe dose for phase II trials.
  • Phase II trials - are designed to examine what effect the drug has on the body (that is, pharmacodynamics) such as heart rate, blood pressure and cognitive effects, depending on the disease the drug is being developed to treat. These studies are usually conducted in 50−100 patients with the disease rather than healthy volunteers as in phase I.
  • Phase III trials - involve larger numbers (100’s) of patients with a particular disease or condition and are usually randomised comparative double-blinded studies. The comparator is either placebo or an active drug already well established as treatment for the disease under investigation, or both. Several phase III trials are usually required by the regulatory authorities. Even with a large-scale phase III program, uncommon adverse events may not be detected until the new medicine is used widely in the community.

Phase IV trials - (post-registration) trials are those undertaken after the new medicine has been registered and are usually randomised controlled trials. Very large studies involving thousands of patients for several years.


After phase I to III the pharmaceutical company compiles all study data for independent assessment by the government regulatory authorities (FDA in the USA, Therapeutic Goods Administration (TGA) in Australia, and Medsafe in New Zealand).

Summarised from VOLUME 29 : NUMBER 6 : DECEMBER 2006 http://www.australianprescriber.com/magazine/29/6/159/61


The World Medical Association (WMA) has developed the Declaration of Helsinki as a statement of ethical principles for medical research involving human subjects, including research on identifiable human material and data. It is widely regarded as the cornerstone document on human research ethics.


2011

A to X: the problem of categorisation of drugs in pregnancy--an Australian perspective

Med J Aust. 2011 Nov 21;195(10):572-4.

Kennedy DS. Source MotherSafe, Royal Hospital for Women, Sydney, NSW, Australia. debra.kennedy@sesiahs.health. nsw.gov.au Comment in Med J Aust. 2012 Feb 20;196(3):172; author reply 172-3. Med J Aust. 2012 Feb 20;196(3):172-3.

PMID 22106996

https://www.mja.com.au/journal/2011/195/10/x-problem-categorisation-drugs-pregnancy-australian-perspective