Pharmacodynamics

Question 1

What is a drug class?

Answer 1

a grouping of drugs that work by similar mechanisms of action, or that produce a similar physiological, biochemical, or clinical response

Question 2

2 aims of drug therapy?

Answer 2

maximize efficacy and minimize adverse effects (detailed answer: rapidly deliver and maintain therapeutic, yet nontoxic levels of most appropriate drug in target tissue so that the disease is treated without adversely affecting the patient)

Question 3

To accomplish the 2 aims of drug therapy, you must know what 4 components?

Answer 3

need to know what, how much, how long, and to who

Question 4

Name 5 questions to answer before prescribing a drug

Answer 4

Which class of drugs? Which drug in that class? Are drug combinations appropriate? What dose? How often? By what route? How long to use for? What benefit to expect, and how soon can you expect it? What adverse effects to monitor for and/or manage? Withdrawal time?

Question 5

What is an international non-proprietary (INN) or generic drug name?

Answer 5

A unique name for a drug that is globally recognized and public property; identifies a pharmaceutical substance or actor pharmaceutical ingredient

Question 6

What is a generic product?

Answer 6

Product using a drug that is not patent protected

Question 7

What is an approved drug?

Answer 7

Drug with demonstrated efficacy and safety for label claims; a country- and species-specific process

Question 8

What is extra-label drug use? Is it legal?

Answer 8

Using a drug in a manner inconsistent with its label claims, whether this is regarding species, disease, dose, or route of administration. Legal for veterinarians to do, but has certain responsibilities to follow.

Question 9

What is the Compendium of Veterinary Products (CVP)?

Answer 9

Compendium which includes all veterinary approved products in Canada

Question 10

When the formulation of a drug is changed, typically the ____ properties stay the same but the ______ may change.

Answer 10

Pharmacodynamic properties stay the same but the pharmacokinetics may change when the formulation is changed

Question 11

What is drug or pharmaceutical formulation?

Answer 11

Process through which a variety of substances are combined with the drug’s active pharmaceutical ingredient (API) to finally produce a drug product that can be successfully given to patients

Question 12

What is the basic difference between pharmacodynamics and pharmacokinetics?

Answer 12

Pharmacodynamics is what a drug does to the body (how the drugs interacts with and affects biological systems). Pharmacokinetics is what the body does to the drug (processes of absorption, distribution, metabolism, elimination).

Question 13

What are the 8 principles of pharmacodynamics?

Answer 13

Drugs act primarily through molecular targets; receptor types determine response to many drugs; receptors can be on or off; multiple mechanisms of antagonism exist; efficacy is not the same as potency; receptors are not static; selectivity is important; body tries to maintain homeostasis

Question 14

Definition of drug target?

Answer 14

Where a drug binds or interacts to produce pharmacological effect

Question 15

What is a receptor?

Answer 15

Cell surface or intracellular protein that receives and transducer a signal; specific type of target with unique pharmacologic properties

Question 16

Name at least 4 drug targets

Answer 16

Receptors, enzymes, ion channels, transporters. Less important ones to remember are cell membranes, carrier molecules, structural proteins, DNA, RNA

Question 17

What is affinity?

Answer 17

Strength with which a drug binds to its target

Question 18

Which type of activation involves ion channels opening or closing and has an immediate effect without any second messenger molecules or processes?

Answer 18

Direct activation

Question 19

Which type of activation involves translation of receptor activation through downstream signals before achieving its eventual effect?

Answer 19

Signal transduction

Question 20

Endogenous ligands and receptor agonists both result in signal ____.

Answer 20

transduction

Question 21

Name at three classifications of drug antagonists

Answer 21

Non-competitive antagonists (bind receptors at site other than that bound by agonists of that receptor). Competitive antagonists (bind at same site as agonists would). Irreversible antagonists (same binding site, no out-competition possible)

Question 22

Name 4 main types of receptors. Which type is fastest to respond?

Answer 22

ligand-gated ion channels (ionotropic receptors) - take milliseconds to respond.
G-protein coupled receptors - take seconds to respond.
Kinase-linked (enzyme-linked) receptors - take hours to respond.
Intracellular receptors - take hours to days to respond.

Question 23

Which receptor type involves signal amplification?

Answer 23

G-protein coupled receptors. Signal amplification refers to more than one G-protein can be activated by the receptor and activated G proteins persist longer than the activated receptor.

Question 24

what does receptor type determine in regards to pharmacodynamics?

Answer 24

nature of response to a drug and speed of that response

Question 25

with regard to receptor subtype, what 3 things do the effects of a drug depend on

Answer 25

what receptors it affects, how in interacts with them, and were those receptors are located

Question 26

____ binding to a receptor will turn it on

Answer 26

agonist

Question 27

____ binding to a receptor will turn it off or decrease its response

Answer 27

antagonist

Question 28

in the presence of a competitive antagonist, the dose response curve shows what kind of shift can the maximum effect still be attained?

Answer 28

parallel shift. maximum effect can be attained if more ago sit is present

Question 29

in the presence of a non-competitive antagonist, the dose response curve shows what kind of movement? can the maximum effect still be attained?

Answer 29

decreased maximal response. no.

Question 30

what is the difference between efficacy and potency?

Answer 30

efficacy refers to how effective a drug is at producing a response; potency refers to the concentration of the drug needed to produce a response

Question 31

what is the EC50 or half maximal effective concentration?

Answer 31

the concentration of drug that gives a response equal to half of the maximal response

Question 32

in general, does potency influence the dose of the drug we need to use OR which drug we choose?

Answer 32

potency influences dose (efficacy influences which drug)

Question 33

in general, does efficacy influence the dose of the drug we need to use OR which drug we choose?

Answer 33

efficacy influences which drug (potency influences dose)

Question 34

what is the difference between clinical and pharmacological efficacy?

Answer 34

clinical efficacy is the magnitude and percent of clinical response, while pharmacological efficacy is inhibition or activation of receptor activity

Question 35

potency and efficacy depend on what two basic factors? (hint: involves an effect)

Answer 35

what effect you are interested in and how you are measuring it

Question 36

what is a partial agonist

Answer 36

a drug that binds to its receptor and turns it on but not to its maximum effect

Question 37

through what processes could receptors become desensitizes, down-regulated, or refractory to stimulation?

Answer 37

change in number of receptors; change in receptor responsiveness

Question 38

many drugs bind to more than one receptor type. why should we care?

Answer 38

adverse effects! (increasing the dose of a drug will cause it to affect targets other than its principal one)