Talk:Australian Drug Categories
|About Discussion Pages|
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 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)
Typical testing of new drug compound today involves a lengthy series of animal and human 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.
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. firstname.lastname@example.org. 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.