VPT 421: Veterinary Toxicology (2+0)

PHARMACOKINETICS AND RESIDUES

• How a drug or a combination of drugs behaves in the body after administration not only is important from a therapeutic point of view but is of paramount importance to the producer and the veterinarian in order to prevent residues in the edible tissues after the disease process has been resolved and the animal is slaughtered.
• For therapeutic usefulness and drug residue determinations, a known amount of drug is administered to a healthy animal. Serum concentration data are collected and mathematical models are created so that the overall disposition of the drug in the body can be evaluated in relation to absorption, distribution, metabolism and elimination.
• If the half-life of the drug in the muscle is doubled, perhaps due to a disease state, then the elimination half-life would also double, thereby increasing the risk of violative drug residues in the edible tissues of that animal.
• Drugs that have a slow rate of elimination from body will tend to have protracted half-lives, whereas those that are eliminated quickly will have shorter half-lives.