Pharm Kinetics & Dynamics PowerPoint

Question 1

In general, pharmacokinetics are?

Answer 1

What the body does to a drug once administered

Question 2

In general, pharmacodynamics are?

Answer 2

What a drug does to the body

Question 3

Would you need a bigger or smaller dose if a drug has a high bioavailability?

Answer 3

Smaller. More available, don’t need to give as much.

Question 4

What system is essential for delivery of drugs to various tissues

Answer 4

vascular system

Question 5

Do bound or unbound drugs enter organs, muscles, fats and bind to receptors

Answer 5

Unbound. Cannot bind to receptors or pass through membranes when bound to albumin

Question 6

If drugs are highly protein-bound, would you need a higher or lower dose?

Answer 6

Higher dose. Less free drug is available when bound.

Question 7

What are nondrug properties that influence uptake?

Answer 7

Amt of blood flow to tissue
Concentration gradient of drug across membrane.

Question 8

When pH = pKa of a drug, how is drug ionization affected?

Answer 8

ph = pka of a drug:
50% ionized
50% nonionized form

Question 9

When a drug is in its ionized form, what is its solubility and ability to cross membranes

Answer 9

Water Soluble (polar)
Unable to easily penetrate lipid cell membranes

Question 10

When a drug is in nonionized form, what is its solubility and ability to cross membranes?

Answer 10

Lipid Soluble (nonpolar)
Diffuses across cell membranes easily. Like Blood-brain barrier, gastric cells, placental barriers

Question 11

How does pKa relate to acid base dissociation?

Answer 11

Pka is the negative log of the equilibrium constant of the acid or base. The pH at which the drug is 50:50 ionization

Question 12

What is the most abundant plasma protein

Answer 12

albumin

Question 13

High protein binding results in what kind of plasma concentrations?

Answer 13

High plasma concentration. Low tissue/target receptor concentrations

Question 14

The number of protein binding sites for a drug is finite. How can we “overcome” this?

Answer 14

By adding more drug, we can surpass the amount of protein binding sites available and force drug out of plasma and across membranes

Question 15

Receptors have what three common properties?

Answer 15

Sensitivity
Selectivity
Specificity

Question 16

What are the 5 types of bonds drugs and receptors form?

Answer 16

van der Waals
Hydrophobic
Hydrogen
Ionic
Covalent

Question 17

Do drug receptors need to be completely saturated to elicit effect?

Answer 17

No. Complete saturation of available receptors with drug is not necessary for a desired tissue response. This is due to sensitivity.

Question 18

What is affinity

Answer 18

Degree of attraction b/t a drug and its receptor on the cell’s surface

Question 19

What is efficacy

Answer 19

a drugs capacity to produce an effect

Question 20

How are compartment models useful?

Answer 20

Useful for predicting serum concentrations and changes in drug concentrations in other tissues

Question 21

The single-compartment model is NOT sufficient to describe many drugs, including?

Answer 21

Lipid-soluble anesthetic drugs. Such as propofol.

Question 22

What is the equation for volume of distribution

Answer 22

Vd= dose of drug / plasma concentration

Question 23

What is the effect of enzyme induction?

Answer 23

Increase in enzymes.
System can break down more agent that uses the same enzymatic system for biotransformation
-leads to reduced half-lives

Question 24

Describe First-Order Kinetics

Answer 24

Drug is cleared at a rate proportional to the amount of drug present in the plasma.
-Always a proportional rate, a percentage.
-Negative exponential curve

Question 25

Do most drugs follow First or Zero order Kinetics

Answer 25

First Order

Question 26

Describe Zero Order Kinetics

Answer 26

Is an Amount. (not a proportion or percent)
A constant amount of drug is cleared regardless of plasma concentration.
-Negative Liner Curve

Question 27

Matabolism occurs in two phases. Do all drugs go through phase 1 and then phase 2?

Answer 27

No. Many drugs already possess an appropriate functional group for conjugation and do not need to be modified by a prior phase 1 rxn to be conjugated.

Question 28

Drug is regarded as fully eliminated when ~95% has been eliminated. This usually occurs when?

Answer 28

~4-5 half lives

Question 29

What is clearance?

Answer 29

The volume of plasma completely cleared of drug by metabolism and excreted per unit of time

Question 30

Clearance is directly and inversely related to?

Answer 30

Directly: The dose
Indirectly: The agent half-life and concentration in the central compartment