Session 2 - Pharmacodynamics and Pharmacokinetics 2 Flashcards Preview

ESA 5 - Pharmacology > Session 2 - Pharmacodynamics and Pharmacokinetics 2 > Flashcards

Flashcards in Session 2 - Pharmacodynamics and Pharmacokinetics 2 Deck (26):
1

What is a partial agonist?

Agonist cannot enact 100% response. When in solution with an agonist can act as a competitive antagonist

2

What is drug Specificity and drug selectivity?

Specificity - Targets only one subtype of a receptor e.g. beta2

Selectivity - Targets all types of a particular receptor e.g. beta receptors

3

What is affinity?

Tendency of a drug to bind to a specific receptor type

4

What is efficacy?

Ability of a drug to produce a response as a result of receptor being occupied

5

What is potency?

Dose required to produce the desired biologic response

6

How do you calculate the therapeutic index of a drug?

EC50 (adverse effect) / EC50 (desired effect)

7

How do you calculate the Vd?

Vd = Dose/[Drug]t0

8

What effect does grapefruit juice have on enzymes?

Inhibits several CYP450 isoenzymes

9

What effect does cranberry juice have on enzymes?

inhibits CYP2C9 isoform enzyme

10

How can liver failure impact on drug clearance?

Increased half life, less enzymes

11

How can cardiac disease impact drug clearance?

Reduced organ perfusion of liver and kidneys

12

How does renal failure impact drug clearance?

Less quickly eliminated through waste

13

How would you calculate the loading dose necessary for a drug?

Loading dose = Vd x [drug]target

14

What is the relationship between half life of drug and volume of distribution?

Higher volume of distribution = higher half life

15

How does the multi compartment model affect drug clearance?

Drug can be excreted from different compartments (muscle, fat, plasma) at different rates

16

What are the main routes of administration via the enteral route?

oral, rectal, sublingual

17

What are the primary parenteral routes?

intravenous, intra-arterial, intramuscular, intrathecal, subcutaneous

18

What are the pros and cons of enteral?

pros - cheaper, easier to use, can self administer

cons - drug can be metabolised, slower onset, irritates GI, unsuitable if vomiting (oral)

19

What are the pros and cons of parenteral?

Pros - quick onset, no degradation, dosing can be exact

Cons - must be sterile, requires HCPs, more expensive, unconvenient

20

What are the pros and cons of transdermal delivery?

Pros - steady rate of drug delivery, avoid breakdown by liver

Cons - Suitable only for lipid soluble drugs, relatively expensive

21

Some drugs work at a concentration in the plasma that approaches total saturation of the serum albumin. Why would increasing the dosage of such a drug have a disproportionate effect on the body?

Only the unbound molecules are active. Increasing drug conc when total saturation has reached would result in far more unbound molecules than in previous increases of drug conc

22

How does the blood flow through adipose tissue affect uptake of drugs into adipose?

Body fat has a low blood supply and therefore when drugs are administered acutely only very lipid soluble drugs will partition siginificantly into fat.

However, when a drug is administered chronically then levels of that drug can build up over time in the fat stores

23

What pH drug does albumin mainly bind?

Acidic drugs

24

What 2 factors concerning the drug itself determine the rate of drug absorption from the intestine?

Lipid solubility and ionisation

25

Define bioequivalence

2 drugs that are expected to act in a very similar way

26