Pharmacokinetics

Question 1

Vd equation

Answer 1

amount of drug/desired plasma concentration

Question 2

Volume distribution assumes (2 things)

Answer 2

the drug distributes completely all at once, does not undergo any biotransformation or elimination

Question 3

If a drug is lipophilic/hyrdophilic, it requires a ____/____ amount to achieve a plasma concentration

Answer 3

lipophilic=higher

hydrophilic=lower

Question 4

How do you calculate a loading dose of an IV med

Answer 4

IV dose= Vd x plasma concentration/ bioavailability -which is 1

Question 5

An acid ____ a H+

Answer 5

donates

Question 6

A base ___ a OH+

Answer 6

accepts

Question 7

What is ionization?

Answer 7

The process of when a molecule gains a positive or negative charge

Question 8

Ionized or nonionized is more water soluble?

Answer 8

Ionized

Question 9

Explain the following for nonionized molecules:
Solubility
Active or nonactive?
Hepatic biotransformation?
Renal elimination?
Diffuses across lipid barrier?

Answer 9

Solubility-lipophilic
Active or nonactive-active
Hepatic biotransformation? yes
Renal elimination? no
Diffuses across lipid barrier? yes

Question 10

Explain the following for ionized molecules:
Solubility
Active or nonactive?
Hepatic biotransformation?
Renal elimination?
Diffuses across lipid barrier?

Answer 10

Solubility-hydrophilic
Active or nonactive-nonactive
Hepatic biotransformation? no
Renal elimination? yes
Diffuses across lipid barrier? no

Question 11

What happens when you put a weak acid into a weak base?

Answer 11

It will become ionized. The acid wants to donate it’s protons and the base wants to accept it.

Question 12

What happens when you put a weak acid into an acid?

Answer 12

It will be nonionized. Both acids want to donate their protons so they both retain them.

Question 13

Name the 3 key plasma proteins

Answer 13

Albumin, AAG (alpha-1 acid glycoprotein), beta-globulin

Question 14

Do the following bind to acid or bases? Albumin, AAG, beta-globulin

Answer 14

Albumin-acids, AAG & beta-globulin-bases

Question 15

Which conditions decrease albumin?

Answer 15

Liver disease, renal disease, old age, malnutrition, pregnancy

Question 16

Which conditions increase a1-acid glycoprotein?

Answer 16

surgical stress, MI, Rheumatoid arthritis, chronic pain, advanced age

Question 17

Which conditions decrease a1-acid glycoprotein?

Answer 17

pregnancy, neonate

Question 18

Are protein binding and plasma concentration inversely or directly proportional?

Answer 18

inversely. As protein building increases, plasma concentration decreases.

Question 19

What are phase 1 reactions?

Answer 19

Oxidation, reduction, hydrolysis

Question 20

What is oxidation?

Answer 20

Adds an oxygen molecule to a compound. Involves loss of electrons.

Question 21

What is reduction?

Answer 21

Adds electrons to a compound.

Question 22

What is hydrolysis?

Answer 22

Adds water to a compound to split into 2 parts

Question 23

What is a phase 2 reaction? What happens?

Answer 23

Conjugation, adds an endogenous, highly polar, water substrate to make it inactive and water soluble.

Question 24

What are CP 450 inducers? What happens?

Answer 24

They break down drugs FASTER. Increased clearance, decreased plasma concentration, re-dosing may be needed.
Smoking, barbituates, ethanol, phenytoin, carbamazepine, rifampin

Question 25

What are CP 450 inhibitors? What happens?

Answer 25

``` They SLOW metabolism of drugs. Decreased clearance, increased plasma concentration, may have to decrease dose. Grapefruit Cimetidine Omeprazole Isoniazid SSRI's Erythromycin Ketoconazole ```

Question 26

What is pharmacokinetics?

Answer 26

What the body does to the drug

Question 27

What is pharmacodynamics?

Answer 27

What the drug does to the body

Question 28

What does ADME mean in pharmacokinetics?

Answer 28

A-absorption, D-distribution, M-metabolism, E-elimination

Question 29

Conditions that affect site of absorption

Answer 29

Blood flow, surface area, membrane thickness, metabolism, GI motility, pH, presence of other substance

Question 30

Rate of diffusion equation

Answer 30

Concentraion gradient x SA x diffusion coefficient/ membrane thickness

Question 31

The rate of diffusion is directly proportional to what?

Answer 31

Concentration gradient and SA

Question 32

The rate of diffusion is inversely related proportionally to what?

Answer 32

Membrane thickness

Question 33

What is the definition of bioavailability?

Answer 33

Fraction of unchanged drug that reaches the systemic circulation following administration

Question 34

Aqueous Diffusion: Flow (with or against) a concentration gradient.

Answer 34

concentration, with

Question 35

Lipid Diffusion: goes from (greater/less) to (greater/less) concentration.

Answer 35

greater to less

Question 36

Active transport diffusion

Answer 36

uses ATP (Na/K pump)

Question 37

Facilitated Diffusion

Answer 37

Passive action without the use of ATP, (glucose and insulin)

Question 38

Endocytosis diffusion

Answer 38

the wall of the membrane engulfs the molecule. (Phagocytosis, Pinocytosis)

Question 39

Protein binding can affect:

Answer 39

Distribution of drugs, potency, elimination

Question 40

Hepatic microsomal enzymes are mainly found in the ______ of the _____. Examples:

Answer 40

endoplasmic reticulum, liver. Ex: Cytochrome P-450, Acetyl CoA, Transferases

Question 41

CYP-2D6 inducers.

Answer 41

Phenytoin, Carbamazepine, dexamethasone

Question 42

CYP-2D6 Inhibitors

Answer 42

Isoniazid, SSRI's, Quinidine

Question 43

What is absolute bioavailability?

Answer 43

the amount of drug that reaches the systemic circulation from an IV dose

Question 44

What is relative bioavailability?

Answer 44

the amount of drug that reaches the systemic circulation from a non-IV form

Question 45

Name fastest to slowest routes to reach peak plasma concentration:

Answer 45

(I) (T)hink (I) (C)an (P)lease (E)veryone (B)ut (S)usie & (S)ally IV, tracheal, Intercostal, Caudal, Paracervical, Epidural, Brachial Plexus, Sciatic/Subarachnoid, Subcutaneous

Question 46

Ion trapping is:

Answer 46

a build-up of a higher concentration across a cell membrane due to the pKa value and difference in pH across the membrane.

Question 47

Define clearance

Answer 47

volume of plasma that is cleared of drug per unit time

Question 48

What are the major clearing organs

Answer 48

liver, kidney

Question 49

Define steady state

Answer 49

occurs when the amount of drug entering the body is equivalent to the amount of drug being eliminated from the body.

Question 50

Clearance is directly proportional to:

Answer 50

blood flow to clearing organ, extraction ratio, drug dose

Question 51

Clearance is inversely proportional to:

Answer 51

half life, drug concentration in the central compartment

Question 52

How many half-times must elapse to achieve steady state?

Answer 52

5

Question 53

Renal excretion of drugs involves__ (3 things)

Answer 53

glomerular filtration, active tubular secretion, passive tubular secretion

Question 54

Renal clearance is inversely correlated with:

Answer 54

age and creatinine clearance

Question 55

The distribution phase of elimination or the ___ phase is:

Answer 55

alpha; redistribution of drug from the plasma and vessel rich group to the less perfused tissues of the peripheral compartment

Question 56

The elimination phase or ____ phase:

Answer 56

after distribution slows, get slow continuous elimination from the central compartment

Question 57

Weak acids combine with salts to make ____ charged ions

Answer 57

positively. Ex sodium thiopental, sodium nitroprusside

Question 58

Weak bases combine with salts to make ____ charged ions

Answer 58

negatively. Ex: morphine sulfate, lidocaine hydrochloride

Question 59

The higher the pka, the _____ the amount of drug in the nonionized form

Answer 59

greater

Question 60

What is the drug class that doesn't fall into an acid or base?

Answer 60

NMBDs

Question 61

CYP-2D6 deficient individuals have less response to ____

Answer 61

codeine

Question 62

CYP-2D6 inducer individuals have decreased response to ____

Answer 62

Zofran