Toxicology Flashcards
What is an acute toxicity study?
- Give a single dose of drug to an animal - let it sink in for two weeks, then look for order of magnitude response
What is done in a subacute toxicology study?
Use a dose that passed the acute toxicity study, then repeatedly dose animals - give for 14 days - and examine their histopathology
What is a chronic toxicology study?
Give a non-toxic dose of a drug for up to two years- then kill animal to study histology
What is the NOAEL?
“No observed adverse effect level”= defined as the highest dose tested that does not cause a statistically significant toxic response
What is a problem with the NOAEL?
must be a tested dose
depends on the number of animals used
and depends on assay used
What does LOAEL stand for?
lowest observed adverse effect level = lowest dose tested that generates a statistically significant toxic effect
What is a reference dose?
This is a dose that is taken daily and assumed to be safe in the human population - environmental scientists use this to determine the safe amounts of a chemical in the environment
What is the maximum tolerable dose?
Derived from sub chronic studies - there are multiple definitions of this
1) dose that causes 10% reduction in weight gain- but other measures can also be used
Why is the absolute toxicity not as relevant as the effective/toxic dose?
Because if the effective dose and toxic dose are close together, you’re likely to overdose if you take more than one pill that day. Absolute toxicity isn’t very relevant b/c the effective dose may be much less - therefore overdose is very unlikely
What is the maximum dose you can use in your clinical trials?
it is a tenth of the maximum effective dose used in animal models
What are the three stages of cancer? What constitutes a complete carcinogen?
Initiaion, promotion, progression
a complete carcinogen has all three activities
What are the classifications of carcinogenicity?
Class 1 = carcinogenic
Class 2 - probably carcinogenic
Class 3 - not enough data to say one way or another
Class 4 = no evidence of carcinogenicity
What is the Ames test?
Test for mutagenicity- but tests have proven that mutagenicity does not equate to carcinogenicity b/c it only effects the first stage of cancer development, but does not necessarily promote tumour growth
What is the 3 test genotoxicity Battery ?
3 required test for gene toxicity
1) test for bacteria gene mutations
2) in vitro test for chromosomal damage in mammalian cells
3) in vivo test for chromosomal damage to rat haematopoietic cells
