Pharmacokinetics

Question 1

ADME acronym

Answer 1

Absorption
Distribution
Metabolism
Elimination

Question 2

Dose-effect relationship for pharmacokinetics

Answer 2

Pharmacokinetics: dose - concentration part
Pharmacodynamics: concentration - effect part

Question 3

The time it takes for a drug to be _____ and
______ mainly accounts for the appearance of its effects: onset of action

Answer 3

absorbed and distributed

Question 4

The time it takes for _____ and _____ accounts for the disappearance of a drug’s effect

Answer 4

metabolism; elimination

Question 5

_____: involves the movement of a drug from the site of application into the bloodstream

Answer 5

Absorption

Question 6

Rate and amount of drug absorbed depend on these factors

Answer 6

• route of administration
• local blood flow
• pH, drug ionization
• water solubility
• lipid solubility
• dose

Question 7

____- the fraction of unchanged drug reaching the systemic circulation by any route

Answer 7

Bioavailability

Question 8

What is the first pass effect?

Answer 8

the fraction of drug lost during the process of absorption

Question 9

____ is a major site of drug metabolism

Answer 9

Liver

Question 10

Pathway of oral drug to reach systemic circulation

Answer 10

oral-> gut-> portal circ. -> liver -> IVC -> heart-> lungs-> heart-> systemic circulation

Question 11

Most drugs are weak _____

Answer 11

acids or weak bases

Question 12

A drug is more readily absorbed and passes through cell membrane if it is uncharged- _____

Answer 12

non-ionized

Question 13

Due to greater blood flow, _____ is often the major site of entry into the bloodstream, rather than stomach (oral route)

Answer 13

duodenum

Question 14

______ - important enzyme for metabolizing endogenous compounds and drug biotransformation in the liver

Answer 14

Cytochrome P450

Question 15

Usually described as the ______; a measure of the apparent space in the body available to\ contain the drug

Answer 15

volume of distribution

Question 16

4 main compartments for drug distribution:

Answer 16

-blood (plasma)
-fat
-extracellular fluid
-intracellular fluid

Question 17

The balance between distribution compartments determined by

Answer 17

-permeability of barriers
-pH within the compartment
-binding capacity
-fat solubility of the drug

Question 18

A protein bound drug cannot do these things:

Answer 18

-diffuse through membranes
-be metabolized
-be excreted
-cause effects

Question 19

What is Vd?

Answer 19

Volume of distribution
the property of the drug which shows how much drug needs to be within the body to get a certain concentration in the plasma

Question 20

Plasma protein binding greatly _____ the amount of drug free in the plasma

Answer 20

reduces

Question 21

Vd formula

Answer 21

Vd = total amount of drug in the body /
concentration of drug in plasma

Question 22

T/F - Drugs with very high volumes of distribution have much higher concentrations in extravascular tissue than in the vascular compartment

Answer 22

T

Question 23

______: the set of chemical reactions and pathways by which living organisms transform chemical substances

Answer 23

Metabolism

Question 24

This process begins as soon as the drug reaches systemic circulation

Answer 24

Biotransformation
* One purpose is to eliminate
metabolic wastes
* Drug converted into a metabolite

Question 25

Most common form of drug inactivation

Answer 25

Active Drug --> inactive metabolites -typically metabolite is more water soluble -enhancing elimination

Question 26

Biotransformation that results in partial loss of activity

Answer 26

Active drug --> active metabolites (heroin--> morphine)

Question 27

Biotransformation that promotes absorption and maybe to bypass first pass elimination

Answer 27

Inactive drug → active metabolite (aspirin)

Question 28

What is a drug example of this type of biotransformation? Active drug → toxic metabolite

Answer 28

Acetaminophen

Question 29

Metabolism phases

Answer 29

* Phase 1: involves formation of a new or modified function group or cleavage – Hydroxylation: most common Phase 1 reaction * Phase 2: involves conjunction with an endogenous substance – Glucuronidation: most common Phase 2 reaction

Question 30

Drugs can act as:

Answer 30

– substrates- material upon which the enzyme acts – inhibitors- results in decreased metabolism of drugs; selective or non-selective inhibition – inducers- results in increased synthesis of P450 enzymes and increased metabolism of drugs

Question 31

How does the GI tract play a role in metabolism?

Answer 31

enzymes in mucosal cells of intestinal wall bacteria in large bowel

Question 32

How does plasma play a role in metabolism?

Answer 32

not a major site; enzymes that degrade drugs such as succinylcholine and procaine

Question 33

T/F with elimination drugs removed unchanged or as one or more metabolites

Answer 33

T

Question 34

the most important organs for drug removal

Answer 34

Kidneys

Question 35

T/F Reduced renal excretion accounts for more adverse drug effects in the elderly than any other pharmacokinetic factor

Answer 35

T

Question 36

Clearance equation

Answer 36

Cu x Vu / Cp Cu- concentration of drug in the urine Vu- rate of urine production Cp- concentration of drug in the plasma

Question 37

Half life of a drug

Answer 37

the amount of time it takes for the blood level (or concentration) of a drug to fall to exactly half of what it was at some previous time

Question 38

Time to reach steady state is____ half lives

Answer 38

4 ½ to 5

Question 39

The higher the Cp, the ____ excretion

Answer 39

Faster

Question 40

When the Elimination rate is proportional to drug concentration, these drugs are following what

Answer 40

first order kinetics

Question 41

When the Elimination rate becomes independent of drug in system, these drugs are following what

Answer 41

zero-order kinetics

Question 42

Which drugs are more easily overdosed

Answer 42

Zero-order kinetics

Question 43

Elimination of constant amount of drug per unit time with

Answer 43

zero-order kinetics

Question 44

Elimination is a constant percentage of drug/unit time with ___

Answer 44

First order kinetics