Lecture 34 & 35

Question 1

Pharmacokinetics are the ____steps of the drugs, from absorption

Answer 1

Pharmacokinetics are the first steps of the drugs, from absorption

Question 2

ADME stands for:

Answer 2

Absorption
Distribution
Metabolism
Excretion

Question 3

Oral - __ _____- portal vein - _____

This is problem as the ____may inactivate the majority of the drug

Answer 3

Oral - GI tract - portal vein - liver

This is problem as the liver may inactivate the majority of the drug = hepatic first pass

Question 4

Injections can be:

Answer 4

injections can be

venous
muscular
arterial (uncommon)

Question 5

Crossing the epithelium, what are the ways in which this can happen?

Answer 5

Through aqueous channels (size and charge limitation)

Across cell membrane (lipid soluble)

via Transporters

Diffusion

Question 6

The fastest method of cell absorption is?

Answer 6

Lipid soluble diffusion

Question 7

true or False:

The uncharged species of a drug are much more likely to be lipid soluble than a charged species

Answer 7

True

Question 8

Aspirin is a weak acid - can change to a ______species in the blood - pH trapped

Answer 8

Aspirin is a weak acid - can change to a charged species in the blood this

Question 9

Endothelial cell in capillary is continuous except for little _____

Answer 9

Endothelial cell in capillary is continuous except for little vesicles

Question 10

Fenestrated capillaries are leaky, the leak

Answer 10

whatever is in the blood,

in both directions

Question 11

Where do you get Fenestrated capillaries

Answer 11

Kidneys, intestines and Liver

Question 12

Brain capillaries have

Answer 12

tight junctions

Question 13

What are the two ways drugs can enter the brain then?

Answer 13

Be lipid soluble or use a transporter, like those used to transport Glucose (GLUT 3?)

Question 14

Fat has a ____blood flow

Answer 14

low

Question 15

With a single capillary (from a drug distribution perspective), the rate of delivery will be depend on __________ and _____

High flow - delivery only dependent on ___________in the blood

Low flow - dependent on _____

Answer 15

With a single capillary (from a drug distribution perspective), the rate of delivery will be depend on concentration and flow

High flow - delivery only dependent on concentration in the blood

Low flow - dependent on both

Question 16

Thiopental is ___-___ dependant

Answer 16

Thiopental is blood-flow dependant

high blood flow in blood - goes in readily.

then leaves after a period of time and disperses around the body (particularly in the fat - high affinity for lipids)

Question 17

Protein binding affects drug distribution and __________

Answer 17

Protein binding affects drug distribution and clearance

Tends to have a longer half-life in the blood

Question 18

Thyroxine - ___% protein bound in the plasma

Answer 18

99.96%

Question 19

Aspirin is readily absorbed into the ______ ____ circulation

Higher conc. in the ______ blood than in systemic circulation so, _____dose is effective in the portal blood

– then acts to acetylate COX in platelets.

Answer 19

Aspirin is readily absorbed into the hepactic portal circulation

Higher conc. in the potrtal blood than in systemic circulation so, low dose is effective in the portal blood

– then acts to acetylate COX in platelets.

Question 20

Hepatic metabolism:

_______drugs
________drugs (prodrugs)
Makes drugs more easily excreted by the _______

Answer 20

Hepatic metabolism:

Inactivates drugs
Activates drugs (prodrugs)
Makes drugs more easily excreted by the kidneys

Question 21

2 Types of reactions in liver, phase 1 and 2:

Phase 1 - modification of _______ ____

Phase 2 - attachment of ______derivative 3 (enhances water solubility)

Answer 21

2 Types of reactions, phase 1 and 2

Phase 1 - modification of functional group

phase 2 - attachment of sugar derivative 3 (enhances water solubility)

Question 22

Secretion is the ______pumping of solutes into the _______

Answer 22

Secretion is the active pumping of solutes into the filtrate:

organic cation transporters
organic anion transporters.

Question 23

Secretion can also occur in the ______, where drugs are pumped into the _____- then reabsorbed.

Answer 23

Secretion can also occur in the liver, where drugs are pumped into the bile - then reabsorbed.

Question 24

Lipid soluble drugs tend to be eliminated inefficiently in the _____, because they come back out of _____in into the blood.

Why the liver is also important - to make _____soluble.

Answer 24

Lipid soluble drugs tend to be eliminated inefficiently in the kidney because they come back out of urine in into the blood.

Why the liver is also important - to make water soluble.

Question 25

Bioavailabilty is the fraction of the drug reaching ______circulation that is administered.

Answer 25

Bioavailabilty is the fraction of the drug r4eaching systemic circulation that is administered.

Question 26

What are some things that can affect bioavailability?

Answer 26

intestinal transit time
stomach emptying time (acid secretion can be inhibited to help)

for destruction:
hepatic disease
competition between drugs and enzymes
enzyme inhibitors

Question 27

Volume of distribution is:

Answer 27

amount of drug in body / plasma drug concentration

the volume which would have to hold the amount of drug in the body for it to be at a concentration equal to the plasma drug concentration

Question 28

V (d) is influenced by:

Answer 28

Protein distribution

Access to body compartments

Lipid solubility