Pharmacodynamics

Question 1

Define pharmacodynamics.

Answer 1

what the drug does to the body.

Question 2

Define ligand.

Answer 2

a molecule that is able to bind to a complex with a receptor to produce a biological response.

Question 3

What is an endogenous ligand?

Answer 3

created inside the body. ex: neurotransmitters/hormones

Question 4

What is an exogenous ligand?

Answer 4

can mimic structures of endogenous or be slightly different but still bind to receptor sites.

Question 5

Name the 4 types of receptor-ligand bonds from strongest to weakest.

Answer 5

Covalent, Ionic, Hydrogen, Van de Waals.

Question 6

Which type of bond is irreversible?

Answer 6

Covalent

Question 7

Describe a Van de Waals bond.

Answer 7

2 molecules with electrostatic attraction between bipoles, weak bond

Question 8

Describe a Hydrogen bond.

Answer 8

occurs with negatively charged molecule that has electrostatic attraction to a positively charged hydrogen

Question 9

Describe Ionic bond.

Answer 9

positive and negatively charged molecules attracted

Question 10

Describe covalent bond.

Answer 10

Chemical bond with sharing of electron pairs with atoms.

Question 11

Name the 4 types of receptors.

Answer 11

ligand-gated, g-protein coupled, enzyme linked, intracellular

Question 12

Describe a ligand gated receptor.

Answer 12

as the ligand binds to a receptor, the gates open, activation of the receptor which allows charged substances to enter or exit cell.

Question 13

Name an example of ligand-gated receptor.

Answer 13

Acetylcholine receptors, Sodium/Potassium pumps

Question 14

Describe a g-protein coupled receptor.

Answer 14

more complex, ligand specific to receptor, binds causing structural changes to g-protein inside the cell, activating and released downstream to find effector protein and create a response.

Question 15

Name an example of a g-protein coupled receptor.

Answer 15

GABA receptors

Question 16

Describe enzyme linked receptors.

Answer 16

drug or hormone binds and extracellular ligand transmits and causes enzyme to become activated, goes down to effector protein for effect. Not very applicable to anesthesia.

Question 17

Name an example of an enzyme linked receptor.

Answer 17

tyrosine kinase

Question 18

Describe intracellular receptors.

Answer 18

simplest, ligand small and lacks polarity, passes through phospholipid bilayer and go directly to receptor site.

Question 19

Describe the law of mass action.

Answer 19

assume binding is reversible and binding is due to drugs colliding with receptors from diffusion. Dependent on concentration. Increased concentration=increased likelihood of complexes.

Question 20

True/false: dose response curves factor in time.

Answer 20

false. they are independent of time.

Question 21

What is the x-axis on a dose/response curve? y-axis?

Answer 21

x-axis=dose/potency; y-axis=efficacy

Question 22

Define and give example of a full agonist.

Answer 22

binds to receptor and mimics endogenous ligand. reaches full Emax; fentanyl

Question 23

Define and give example of a partial agonist.

Answer 23

binds to same receptor and activates a partial cellular response, doesn’t reach Emax, agonist/antagonist=competitively blocks other agonists; Nalbuphine

Question 24

Explain the difference between a competitive and noncompetitive antagonist.

Answer 24

Both antagonists bind to a receptor to block it rather than cause a response. Competitive=reversible, increased concentration of agonist can offset effects. Noncompetitive=irreversible/covalent bond, long duration of action, cant be overcome unless new receptor sites formed.

Question 25

Define and give example of an inverse agonist.

Answer 25

binds to receptor causing opposite effect of agonist; inverse efficacy; propranolol, flumazenil

Question 26

Define potency on a dose response curve.

Answer 26

amount of a drug needed to produce an effect, where the curve lies on x-axis. decreased potency to the right.

Question 27

Define efficacy on a dose response curve.

Answer 27

ability of a drug to produce a physiologic or clinical effect, number of drug-receptor complexes formed, efficiency of receptor binding and cellular response

Question 28

Define slope on a dose response curve.

Answer 28

drug receptor affinity, number of receptor ligand complexes. Gentler slope is safer, if steep than the drug has increased affinity and less safety.

Question 29

Name things that cause variation in the population.

Answer 29

Genetics (CYP2D6, CYP2C19), Drug metabolism/liver function (P450), renal function, receptor numbers/structure, age, gender, race, medical history, diet, concomitant drugs, placebo.

Question 30

Which is safer, a wide or narrow therapeutic window?

Answer 30

wide!

Question 31

What is the equation for Therapeutic Index?

Answer 31

TI= LD50/ED50; TD used interchangeably with LD for human studies.

Question 32

Name drugs with narrow TI.

Answer 32

volatile anesthetics, chemo, warfarin, lithium, digoxin, phenytoin. drugs that need peaks/troughs/serum level monitoring.

Question 33

Describe addition combination therapy.

Answer 33

1+1=2. 2 drugs given at the same time added to each other. same MoA

Question 34

Describe Synergism.

Answer 34

1+1=3. 2 drugs given at the same time is greater than the sum of their individual effects. drugs with different MoA

Question 35

Describe Potentiation.

Answer 35

1+0=3. effect of one drug is enhanced by a drug that has no effect of its own. different MoA

Question 36

Describe Antagonism.

Answer 36

1+1=0. simultaneous administration of one drug cancels out the effect of a second drug.

Question 37

Describe metabolic physiologic tolerance.

Answer 37

increase enzyme activity to deactivate drug; alcohol, opioids, barbiturates.

Question 38

Describe tachyphylaxis.

Answer 38

Acute rapid decrease in response to a drug after its administration. typically sudden and not dose dependent.

Question 39

What does tachyphylaxis do to a dose response curve?

Answer 39

shifts curve right, no Emax. will require higher dose to receive some effect.

Question 40

Define stereochemistry.

Answer 40

Study of 3D structures of molecules.

Question 41

Define chiral.

Answer 41

molecules with 3D asymmetry, almost always centered around a tetrahedral bonded carbon, the more chiral carbons, the more enantiomeres in a solution.

Question 42

Define enantiomerism

Answer 42

pairs of molecules existing in 2 forms that are mirror images (likely chiral). Ex: your hands

Question 43

Describe racemic mixtures.

Answer 43

50/50 mixture of left and right handed enantiomeres of a chiral molecule. 1/3 of the drugs we use can be considered racemic. Ex iso and des.