Pharmacokinetics Absorption/Distribution

Question 1

Pharmacokinetics relationship between what 2 things?

Answer 1

dose-concentration

Question 2

Biophase (PK-PD link) reflects what relationship?

Answer 2

plasma-effect site

Question 3

Pharmacodynamics reflects what relationship?

Answer 3

concentration-effect

Question 4

What does ADME stand for?

Answer 4

Absorption, Distribution, Metabolism, Excretion

Question 5

Simply define pharmacokinetics.

Answer 5

what the body does to a drug.

Question 6

Name 4 drug properties that affect absorption.

Answer 6

size, shape, degree of ionization(acidic/alkaline), lipid solubility

Question 7

What conditions at the site affect absorption?

Answer 7

blood flow, surface area, membrane thickness, presence of other substances, metabolism (1st pass hepatic metabolism), GI motility, pH

Question 8

The rate of diffusion is directly proportional to what?

Answer 8

concentration gradient, surface area

Question 9

The rate of diffusion is inversely proportional to what?

Answer 9

membrane thickness

Question 10

What’s Fick’s Law of Diffusion equation?

Answer 10

Rate of diffusion= conc. grad. * SA * Diffusion Coef / membrane thicknss

Question 11

Define Bioavailability.

Answer 11

Fraction of unchanged drug that reaches the systemic circulation following administration by any route

Question 12

Where is the principle route of absorption for oral route?

Answer 12

largest surface area of the small intestine

Question 13

Name 4 medications highly susceptible to first pass hepatic metabolism.

Answer 13

Aspirin, levadopa, metoprolol, morphine

Question 14

What common medication is hydrolyzed in the stomach?

Answer 14

penicillin

Question 15

True/False: Transmucosal meds (SL/buccal/intranasal) are subject to 1st pass hepatic effect.

Answer 15

False

Question 16

What percentage of body weight does water make up in men? women? infants?

Answer 16

60% men; 50% women; 70% infants

Question 17

How many L is total body water?

Answer 17

42L

Question 18

How many L of fluid is intracellular? Extracellular?

Answer 18

28L, 14L

Question 19

What % of CO is central compartment?

Answer 19

75%, peripheral comp. 25%

Question 20

What % of weight is central compartment

Answer 20

10%, peripheral comp. 90%

Question 21

Define Vd and it’s equation.

Answer 21

Vd relates the amount of drug given to plasma concentration. Vd=amount of drug/desired plasma conc.

Question 22

True/False: Small plasma concentration=large Vd.

Answer 22

True.

Question 23

What kind of drugs have large Vd?

Answer 23

Lipid soluble drugs, lipophilic. Needs larger dose for effect. Propofol

Question 24

What kind of drugs have low Vd?

Answer 24

hydrophilic drugs, highly water soluble, higher plasma concentrations. Neuromuscular blocking drugs

Question 25

True/False: Aqueous Diffusion involves lipophilic substances.

Answer 25

False, Hydrophilic substances. Driven by a concentration gradient, small molecular weight, assisted by osmotic or hydrostatic pressure.

Question 26

True/False: Lipid Diffusion is most pertinent to anesthesia.

Answer 26

True. Lipid soluble drugs, cross phospholipid bilayers based on conc. gradient to aqueous side.

Question 27

True/False: acidic drugs bind to alpha1-acid glycoprotein.

Answer 27

False. Acidic (thiopental) bind to albumin. Basic drugs (local anesthetics) bind to alpha1-acid glycoprotein.

Question 28

Name things that decrease albumin thereby increasing amount of free drug in the body.

Answer 28

renal disease, liver disease, old age, malnutrition, 3rd trimester

Question 29

What causes increased alpha1-acid glycoprotein (AAG) binding?

Answer 29

surgical stress, MI, chronic pain, RA, old age.

Question 30

What causes decreased (AAG) binding?

Answer 30

Neonates, 3rd trimester

Question 31

Vd of a drug is directly/inversely proportional to a drug?

Answer 31

inversely, but only when just looking at protein binding, there are many other factors.

Question 32

A drug changes from 98% protein bound to 94% protein bound, by what percentage has the amount of free fraction increased?

Answer 32

started with 2% unbound to 6% unbound, amount doubles twice, increases 200%. In highly protein bound drugs small changes can make a big difference

Question 33

Which are more lipid soluble? ionized or non-ionized?

Answer 33

non-ionized are 1000-10000 times more lipid soluble and rapidly diffuse across cell membranes. larger Vd.

Question 34

Ionized molecules are hydrophilic/lipophilic?

Answer 34

hydrophilic, doesn't cross membranes

Question 35

True/False: non-ionized molecules are negatively charged?

Answer 35

False, neutral charge.

Question 36

What is the order of routes of administration from fastest to slowest to reach peak plasma concentration?

Answer 36

IV, tracheal, intercostal, caudal, paracervical, epidural, brachial plexus, sciatic/subarachnoid, subcutaneous. I Think I Can Please Everyone But Susie & Sally.