Module 3: Toxicology - Section 1: Introduction to Occupational Toxicology

TOX 1.5: Axioms of Toxicology

AXIOMS OF TOXICOLOGY

• There is enough similarity in the biochemistry in similar species to allow for extrapolation from laboratory animal data to human exposure settings.
• Any substance can cause toxicologic injury at a high enough exposure. The dose makes the poison.
• There is a dosage or exposure level that has no effect on the health of animals, as measured by methods which have a finite sensitivity to measure dysfunction or injury, a No Observed (Adverse) Effect Level (NOAEL)
• Toxicological data from animal experiments can be used to determine the dosage that will not adversely affect human health. Potential or real inter and intra species differences dictate that uncertainty factors be applied when extrapolating from animal threshold doses in order to ensure an adequate margin of safety for humans.

REFERENCES:

There is an excellent Toxicology Tutorial available at the National Institutes of Health, National Library of Medicine website at
http://www.sis.nlm.nih.gov/Tox/ToxTutor.html

Postgraduate Diploma in Occupational Health (DOH) - Modules 3: Occupational Medicine & Toxicology (Basic) by Profs Mohamed Jeebhay and Rodney Ehrlich, Health Sciences UCT is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License. Major contributors: Mohamed Jeebhay, Rodney Ehrlich, Jonny Myers, Leslie London, Sophie Kisting, Gail Todd, Neil White. Source available from here. For any updates to the material, or more permissions beyond the scope of this license, please email healthoer@uct.ac.za or visit www.healthedu.uct.ac.za. Last updated Jan 2007.
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