Lecture 1 1/23/24 Flashcards
What constitutes a drug product?
the active and inactive components
What is a drug?
any substance that brings about a change in biologic function through its chemical action
What is a receptor?
a specific molecule that a drug molecule interacts with
What are the potential ways to identify a specific drug?
-chemical name
-chemical abstracts registry number
-generic name
-trade name
Which agencies are involved in the regulation of animal drugs?
-FDA
-USDA
-EPA
-state pharmacy boards
-state veterinary boards
Which products are regulated by the FDA?
-human and veterinary drugs
-biological products
-medical devices
-food supply
-cosmetics
-radiation-emitting products
What is the role of the USDA and APHIS?
-regulate veterinary biologics
-regulate drug residues in edible animal tissues
Which products are regulated by the EPA?
-topically applied parasiticides
-animal facility insecticides/parasiticides
What are the steps of drug approval?
-begins with a sponsor that collects and submits all info about a drug
-NADA process to ensure drug safety, efficacy, and potential adverse environmental effects
-presentation of NADA to FDA; drug can be sold if approved
What are the 5 major sections of the NADA?
-target animal safety
-effectiveness
-human food safety
-chemistry, manufacturing, and controls
-environmental impact
What are the 2 minor sections of the NADA?
-all other information
-labelling
Who determines if a drug is safe for over-the-counter use or must be used under veterinary oversight?
FDA
What are the characteristics of an ANADA?
-abbreviated NADA application for generic drugs
-drugs must be proven to be the same as approved brand name
-bioequivalence must be proven
-generic labelling must match approved brand labelling
What is pharmacokinetics?
-study of the time course of drug absorption, distribution, metabolism, and excretion
-what the body does to the drug
What is kinetic homogeneity?
a predictable relationship between plasma drug concentration and concentration at the receptor site
What is pharmacodynamics?
-study of biochemical and physiological effects of drugs, their modes of action, and the relationship between drug concentration and effect
-how a drug behaves in the body
What is drug action?
initial consequence of drug-receptor combination
What is drug effect?
biochemical and physiological changes that occur as a consequence of drug action
What is the therapeutic window?
range of a drug’s serum concentration at which a desired effect occurs
How is the therapeutic index calculated?
dividing 50% value of toxicity by 50% value of efficacy
How does therapeutic index relate to drug safety?
the wider the therapeutic index, the safer the drug
What values are most important to determine when conducting therapeutic drug monitoring?
-peak: maximum drug efficacy
-trough/low: when to give next dose as to not cause toxicity
What is therapeutic drug monitoring?
-use of assay procedures to determine drug concentrations in plasma
-interpretation of assays to develop safe and effective drug regimens
What are the criteria for conducting therapeutic drug monitoring?
-narrow therapeutic window
-variable pharmacokinetics
-correlation between concentration and efficacy
-no alternative therapies
What is potency?
a measure of drug activity, expressed in terms of the amount required to produce an effect of given intensity
How do higher potency drugs differ from lower potency drugs?
-higher potency drugs will evoke a given response at low concentrations
-lower potency drugs can only evoke the same response at higher concentrations
What is drug efficacy?
-the maximum effect that can be achieved by a drug
-how well a drug produces a desired effect
What is important about the relationship between potency and efficacy?
high potency does not imply high efficacy
What is EC50?
concentration required to achieve 50% maximal effect of a drug
When comparing two drugs, how is it possible to determine the more potent drug?
the drug with the lower EC50 has greater potency
Which should be favored clinically, efficacy or potency?
efficacy
What are agonists?
drugs that occupy receptors and activate them
What are antagonists?
drugs that occupy receptors but do not activate them
What is a partial agonist?
drug that acts at a receptor but produces less than maximal effect
What is competitive inhibition?
inhibition of a pathway due to one substance competing with another substance
Is the effect of a competitive antagonist able to be overcome? If so, how?
-yes
-increasing the dose of the agonist can negate the effect of the antagonist
What are the two potential types of noncompetitive inhibition?
-irreversible binding of antagonist at the receptor
-interaction of the antagonist at a site away from the receptor that prevents initiation of effect
Is the effect of a noncompetitive antagonist able to be overcome? If so, how?
not completely
What are the characteristics of pharmacodynamic tolerance?
-response to a given drug concentration is progressively reduced
-concentration needs to keep increasing to maintain the effect
What are the potential mechanisms of pharmacodynamic tolerance?
-decreased receptor affinity/response
-changes in signaling pathways
-decreases in receptor density
-engaging compensatory mechanisms
