Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
27 Cards in this Set
- Front
- Back
|
How do drugs decay in the body
-why |
-exponentially
-first order kinetics |
|
|
Because drug is decreasing in the body exponentially, what does this mean for concentration?
|
-drug will stay in the body for a long time, but will probably not be at a high enough level to cause harm
|
|
|
Withdrawal time
-importance |
-ensure that drug concentrations in edible tissues deplete to levels that are safe for human consumption
-not necessarily when the levels are zero |
|
|
Withdrawal time
-aka |
-withhold time
|
|
|
NOEL
-define |
No Observable Effect Level
-oral dose that results in no toxic effects in test animals |
|
|
NOEL
-use |
-extrapolated to humans from test animals (minimum of 2 species)
|
|
|
Possible adverse effects that can occur when dose is above NOEL
|
-acute toxicity
-microbiological effects -carcinogenicity -teratogenicity |
|
|
ADI
-define |
Acceptable Daily Intake
-the total dose of the drug that an average human could ingest on a daily basis for their entire life |
|
|
Safety Factors
-purpose |
-used to extrapolate the NOEL to the ADI
|
|
|
Safety Factors considered
|
-interspecies extrapolation
-sensitive subpopulations -long-term exposure |
|
|
Safety Factor for large animal drugs
|
-1000x lower than NOEL
-10x for each of the 3 factors |
|
|
Calculating ADI
|
(NOEL/1000) x Avg. human weight
|
|
|
Safe Concentration
-define |
-allowable amount of drug in each of the edible tissues
|
|
|
Safe Concentration
-purpose |
-so human won't consume more than the ADI
|
|
|
ADI of animal parts for typical US diet (Food Consumption Factors)
|
-meat: 300 g
-Liver: 100 g -Kidney: 50 g -Fat: 50 g |
|
|
Calculating Safe Drug Concentrations for meat
|
ADI / Food Consumption Factor
|
|
|
Tolerance
-define |
-Allowable concentration of marker residue in edible tissue
|
|
|
Marker residue
-define |
-drug residue in known proportion to other residues so that not all residues need to be measured
|
|
|
How to calculate Total Drug Conc.
|
parent drug + metabolites
|
|
|
Determining tolerance
|
-carcass is tested for only one compound (marker residue)
-test of target tissue |
|
|
Target tissue
-define |
-tissue from which marker residue depletes the slowest
-typically liver or kidney because they are metabolizing organs so the drug will leave these organs last |
|
|
Tolerance
-calculation |
Safe Conc. x Proportion of marker residue
|
|
|
Withdrawal Time
-definition |
-time for marker residue in target tissue to deplete to concentrations below tolerance
|
|
|
How is withdrawal time determined
|
-give at known conc. to animals then slaughter at different times and measure the drug conc. levels in the target tissues
-withdrawal uses the upper 99th percentile of the population with 95% confidence |
|
|
Residue violation
-typically determined where |
-slaughterhouse
|
|
|
Extralabel drug uses that can result in residue violations if not compensated for correctly
|
-dose
-route of administration -duration of treatment -volume per injection site -species |
|
|
Extralabel drug use is allowed when?
|
-if enough information is available to calculate an extended withdrawal interval
|
