Phamacodynamics

Question 1

what is pharmacodynamics

Answer 1

study of the biochemical and physiological effects of drugs and their mechanisms of action, including the relationship between the dose (or concentration) of a drug and the effect it produces

Question 2

the effects of most drugs results from what

Answer 2

their reversible association with a functional macromolecular component of the cell

Question 3

what is a receptor or “drug target”

Answer 3

a functional macromolecular component

Question 4

the receptor is a component of what

Answer 4

a cell or organisms that interacts with a drug and initiates the chain of biochemical or physiological events lead to the effects of the drug

Question 5

what are the general types of drug receptors for endogenous physiological regulatory molecules

Answer 5

• neurotransmitters
• hormones & growth factors
• autocoids (substances which are formed and act locally)

Question 6

other cellular proteins or constituents of drug receptors

Answer 6

• enzymes
• transport proteins; carrier molecules
• ion channnels
• structural proteins
• nucleic acids; nuclear transcription factors/elements

Question 7

define agonists

Answer 7

drugs that mimic the effects of endogenous ligands by interaction with the same receptor

Question 8

define antagoinists

Answer 8

compounds that inhibit the response of a specific agonist by competition for binding sites

Question 9

how are drug receptors identified or classified

Answer 9

on the basis of the relative potencies of structurally related agonists and the effect or lack thereof, of selective antagonists or agonists

Question 10

what are the major signalling mechanisms

Answer 10

1. intracellular response elements; transcription factors; DNA-coupled receptors
2. transmembrane enzymes, including tyrosine protein kinases
3. ligand gated ion channels (iontropic)
4. G protein coupled receptors (metabotropic)

Question 11

see diagrams: slide 6-9

Answer 11

see diagrams: slide 6-9

Question 12

name a few drug actions not mediated by receptors

Answer 12

1. chelating agents
2. antacids
3. chemical neutralization
4. osmotic diuretics

Question 13

what are chelating agents

Answer 13

drugs used to treat pts whose body is heavily burdened or has high levels of toxic metals; chelating agents bind heavy metals, take them to the kidney and excrete them; only interacting with heavy metal, not other body tissue

Question 14

what are antacids

Answer 14

neutralize stomach acid, don’t interact with receptor

Question 15

what are chemical neutralization

Answer 15

treat certain toxicities. Ex. Heprain a coagulant is a heavily charged polysaccharide. If too much heparin is in the body the pt will start to bleed. The anecdote for heparin is to squirt in protame which is heavily positively charged

Question 16

what are osmotic diuretics

Answer 16

manatal, works as an osmotic particle exerting coagulative propeties, gets filtered in the glomerulus, doesn’t get reabsorbed and then draws water in with it bc of its osmotic properties and increases urine formation; not interacting with receptors

Question 17

see diagrams: slide 12-13

Answer 17

see diagrams: slide 12-13

Question 18

what is the spare-receptor concept

Answer 18

-a maximal effect can be produced by a drug when only a small proportion of receptor is occupied; the response is not linearly proportional

Question 19

see diagrams: slide 15+16

Answer 19

see diagrams: slide 15+16

Question 20

efficacy

Answer 20

• the maximum effect of a drug is termed efficacy
• this term does not refer to the therapeutic efficacy of the drug, but to the stimulus properties of the drug receptor complex

Question 21

potency

Answer 21

• is a comparative measure that refers to the different doses of two drugs that are needed to produce the same effect

Question 22

(Full) Agonist

Answer 22

-is a drug capable of generating a maximal response

Question 23

Partial Agoinst

Answer 23

• is a drug that will generate a response, but that response is less than the maximum

Question 24

antagonist

Answer 24

• is a drug that reduces the effect of an agonist (an agonist must be present?)

Question 25

inverse agonist

Answer 25

• is a drug that stabilizes an “active receptor” in the inactive conformation

Question 26

see diagrams: slide 18-21

Answer 26

see diagrams: slide 18-21

Question 27

what are they types of drug antagonism

Answer 27

1. competitive
2. noncompetitive
3. physiologic (functional)
4. Chemical (neutralization)

Question 28

see diagrams: pic 23-26

Answer 28

see diagrams: pic 23-26

Question 29

what pharmacodynamic changes occur with aging

Answer 29

• CNS more “sensitive”
• Beta adrenoceptors “less sensitive”
• orthostatic hypotension is more common
• potassium, electrolyte imbalance is more common
• the incidence of occult blood loss with aspirin or NSAIDs is higher

Question 30

what is heterogeneity in the elderly

Answer 30

aging associated with physiologic decline and an increase in the prevalence of disease

Question 31

how is heterogeneity in the elderly slowed

Answer 31

by maintaing physical fitness

Question 32

what clinically impacts heterogeneity in the elderly

Answer 32

• increased biologic variation is characteristic of this age group
• physiologic functions that affect drug disposition
• each pt must be evaluated individually

Question 33

geriatric prescribing

Answer 33

-Adequate review of patient medication regimens; obtain a detailed drug history
-Critically address whether drug therapy is indicated at all; reevaluate drug use at frequent intervals
-Consider physiologic or pathologic changes that may affect drug response
-Pick endpoints to follow carefully
Start low and go slow
-Communicate effectively; enhance patient compliance; emphasize the alliance with the patient