Pharmacokinetics 1

Question 1

pharmacokinetics studies what 3 things?

Answer 1

how drugs enter and leave the body. plasma drug concentrations vs. time. what the body does to a drug.

Question 2

ADME

Answer 2

absorption from site of administration. distribution within body. metabolism. excretion.

Question 3

pharmacokinetic properties of drugs are ___ and ____? provides what clinically relevant information (4)?

Answer 3

distinct + drug specific. optimal route of drug admin, required drug dose + dosing interval, variations in drug levels in disease, how to optimize drug therapies

Question 4

movement of drug molecules in body: 3?

Answer 4

bulk flow, passive diffusion, transport/carrier systems.

Question 5

movement of drug molecules in body: bulk flow?

Answer 5

drug moves in bloodstream around body, lymphatic system, cerebrospinal fluid

Question 6

movement of drug molecules in body: passive diffusion depends on?

Answer 6

drug concentration gradient. rate is very drug specific, depends on ionization/lipid solubility, molecular size.

Question 7

2 types of drug administration

Answer 7

systemic: use blood as delivery system. local: drug given directly to site of action.

Question 8

oral administration: aka? absorption %?

Answer 8

enteral administration. less than 100%

Question 9

why is GI tract absorption less than 100%? (6)

Answer 9

disintegration/solubility. drug ionization. stability (stomach acid). gastric emptying, GI motility. GI blood flow. first pass effect

Question 10

gastric emptying/GI motility: most of drug absorbed where? slowed by?

Answer 10

upper GI. gastric emptying slowed by food.

Question 11

bio-availability def? aka? partial loss due to?

Answer 11

“F”: perception of dose entering circulation. partial loss due to metabolism or excretion.

Question 12

first pass effect: aka? what?

Answer 12

pre-systemic elimination. GI blood first enters hepatic portal circulation so partial loss due to metabolism or ecretion.

Question 13

first pass effect: direct effect on? likely to vary with? examples?

Answer 13

therapeutic outcome, varies with liver function. ASA 30% lost. morphine 70% lost. nitroglycerin 99% lost.

Question 14

advantages of oral route (3)

Answer 14

no need for drug to be pure/sterile. common, easy for patient, no pain. cheap formulations, multi dose bottles.

Question 15

disadvantages of oral route (5)

Answer 15

requires conscious cooperative patient. slow so not good for emergencies. variable absorption/bioavailibility. loss of drug if patient vomits. potential for upper GI tract irritation.

Question 16

rectal administration: speed? first pass effect?

Answer 16

rapid absorption possible; less first pass effect.

Question 17

rectal administration: good for patients who?

Answer 17

cannot swallow, unconscious. won’t swallow - children or psychotics. may be vomiting

Question 18

parental means? does not mean?

Answer 18

NOT by enteral route, doesn’t mean only by injection

Question 19

sublingual route: what? ___ entry to? first pass?

Answer 19

drug place under tongue = direct entry to systemic circulation, no first pass

Question 20

sublingual route: speed? pH? so? pros?

Answer 20

rapid absorption despite low area. pH about 7 so avid labile drugs are stable. fast, easy, comfortable.