Overview of Pharmacology: Part 2

Question 1

Distribution

Answer 1

Process by which the drug becomes available to body fluids and body tissues

Question 2

Distribution process

Answer 2

Blood flow to tissues > Exiting the vascular system > Entering the cells

Question 3

Protein binding

Answer 3

Drugs are distributed in the plasma > bound to protein

Question 4

Only _____ _____ are active and can create a pharmacologic effect

Answer 4

Free drugs

Question 5

Competition exists between drugs for…

Answer 5

Protein binding sites

Question 6

When a drug is bound to albumin, it..

Answer 6

Does nothing

Question 7

Bioavailability

Answer 7

The amount of drug available for use by the body (free drug)

Question 8

What does the protein do over time?

Answer 8

Releases the drug, allows for a certain amount to be present at any given time

Question 9

When two drugs compete for binding to albumin…

Answer 9

One loses and has a much higher level of free drug in the blood

Question 10

In protein-binding competition, Coumadin (warfarin)….

Answer 10

Will always lose and be in high amounts in the blood

Question 11

Drug metabolism

Answer 11

Process by which the body inactivates or bio transforms the drug

Question 12

Primary site of drug metabolism

Answer 12

Liver

Question 13

Usually a drug has been ___ by the time it is metabolized

Answer 13

Used

Question 14

Hepatic Enzyme System is AKA

Answer 14

Cytochrome P450 Family

Question 15

P450 System

Answer 15

Group of 12 closely related enzyme families, performs drug metabolism in liver

Question 16

How are the enzymes named?

Answer 16

CYP1, CYP2, etc

CYP2D6

Question 17

Every single P450 enzyme..

Answer 17

Has a group of drugs that it metabolizes

Question 18

If you give two drugs at the same time that are metabolized by the same enzyme…

Answer 18

One will be metabolized and one will not

Question 19

Does drug metabolism always result in the breakdown of drugs?

Answer 19

No! It can also result in the synthesis of molecules larger than the parent drug

Question 20

Consequences of drug metabolism

Answer 20

Accelerated renal excretion
Drug inactivation 
Decreased toxicity
Increased toxicity
Activation of prodrugs
Increased therapeutic action

Question 21

Increased therapeutic action (liver)

Answer 21

Ex: when codeine is metabolized in the liver, it becomes chemically similar to morphine

Question 22

Activation of prodrugs (liver)

Answer 22

Prodrugs are given as physiologically inert drugs, converted in the liver to active drugs (Dopamine for Parkinson’s)

Question 23

Increased toxicity (liver)

Answer 23

Ex: Tylenol taken in too large of a dose follows a metabolic pathway that creates metabolites that destroy the liver (Ibuprofen is similar w/ kidney)

Question 24

Factors in drug metabolism

Answer 24

Age
Induction of drug-metabolizing enzymes
First-pass effect
Competition between drugs

Question 25

An infant's liver enzyme system does not even mature until...

Answer 25

6 months

Question 26

Induction of drug metabolizing enzymes example

Answer 26

Phenytoin: old anti seizure medication, induces the P450 enzymes so that any drug given will get metabolized quickly

Question 27

First pass effect

Answer 27

Oral drug goes through GI, then hepatic portal vein to liver, liver metabolizes certain amount of drug before it has even been to the tissues

Question 28

The higher the first-pass effect...

Answer 28

The higher the dose necessary

Question 29

First pass effect explains the difference between dosages in...

Answer 29

Oral vs. IV

Question 30

Excretion (methods)

Answer 30

``` Renal (main excretor) Breast milk Bile Lungs Sweat / saliva ```

Question 31

Why do we want anesthetic patients to wake up?

Answer 31

So that they can breathe deeply and excrete the drug via the respiratory route

Question 32

Plasma drug levels (3 levels)

Answer 32

Minimum effective concentration Therapeutic range Toxic concentration

Question 33

Minimum effective concentration

Answer 33

Plasma drug level below which therapeutic effects will not occur

Question 34

Therapeutic range

Answer 34

Objective of drug dosing

Question 35

There is a window between...

Answer 35

MEC and toxic concentrations- we prefer this to be large

Question 36

Loading dose

Answer 36

Takes a while to get into therapeutic range, we give a larger amount of drug to get patient into therapeutic range

Question 37

Drug Half-life

Answer 37

The time takes for one half of the drug concentration to be eliminated

Question 38

Repeated dosing of medications can help cause..

Answer 38

Plateau levels, reducing fluctuations

Question 39

Morphine has a half life of 3 hours. If 50 mg were given at noon...

Answer 39

3pm- 25mg 6pm-12.5mg 9pm-6.25mg

Question 40

Pharmacodynamics

Answer 40

What the drug does to the body