Pharmacokinetics

Question 1

Define pharmacokinetic

Answer 1

This is the study of drug disposition and focuses on the changes in the drug plasma concentration.

Question 2

The plasma drug concentration of any drug will change.its will either rise or fall depending on which processes.

Answer 2

A. Absorption
B. Distribution
C.elimation
- metabolism)
-excretion)

Question 3

Which processes makes up biotransformation

Answer 3

Metabolism and excretion

Question 4

What is metabolism

Answer 4

This is the breaking down of the parent drug Into one or more metabolites.Mostly done by liver

Question 5

The excretion of the parent drug or metabolites is done by what.

Answer 5

It’s primarily done by the kidney

Question 6

What is absorption

Answer 6

This is the passage of drug molecules from the site of administration into the systemic circulation

Question 7

Absorption applies to all routes expect for two routes . name those routes giving reasons why

Answer 7

• The topical route.
  This is because drugs administered topically are directly applied on the target tissue.
• The lV route
  This is because drugs administered through the IV route are directly delivered into the circulation.

Question 8

Orally administered drugs have been found to face a greater barrier than the parenteral route True/ False

Answer 8

True

Question 9

Absorption is dependent on three major forms of transport.which are….

Answer 9

Passive diffusion
Active transport
Facilitated diffusion

Question 10

By which processe are most drugs absorbed

Answer 10

Passive diffusion across the biological barrier

Question 12

How is passive diffusion across a biological barrier achieved .

Answer 12

It’s accomplished either through lipid diffusion or aqueous diffusion

Question 14

What is lipid diffusion

Answer 14

This involves the dissolving of a drug in the lipid components of the cell membrane.

Question 15

What is the important facilitator for the process of lipid diffusion.

Answer 15

Lipid solubility

Question 16

What is aqueous diffusion

Answer 16

This involves the absorption of the drug molecules through the aqueous pores of the cell membrane.

Question 17

Aqueous diffusion is restricted by ……….of drugs and thus many drugs are too large to be absorbed by this process.

Answer 17

Molecular weight

Question 18

State Ficks law

Answer 18

This states that the rate of absorption is proportional to the concentration gradient across the barrier and the surface area available available for absorption at the site.

Question 19

What is active transport

Answer 19

This is a process that requires a carrier molecule and energy provided through the high energy phosphate bond of adenosine triphosphate (ATP)

Question 20

Give an example of a drug that can be transported against the concentration gradient.

Answer 20

5- fluouracil an antineoplastic drug

Question 21

What is facilitated diffusion

Answer 21

This is a process that needs a carrier molecule but no energy is needed.

Question 23

Which process cannot transport drugs against concentration gradient but diffusion is enhanced when the carrier molecule is absent.

Answer 23

Facilitated diffusion

Question 24

Which process Can transport drugs against the concentration gradient

Answer 24

Active transport

Question 25

Cephalosporines like cephalexin undergo facilitated diffusion by ............in .........

Answer 25

- oligopeptide transport protein..in intestinal epithelial tissues

Question 26

Generally ,many drugs exist as acids or bases , both existing as either...

Answer 26

Ionized form or non ionized from

Question 27

The non ionized form of drugs are sufficiently soluble in membrane lipid to cross the cell membranes and the ratio of the concentration of the ionized to the non ionized at a particular site influences what.

Answer 27

The rate of absorption

Question 28

In the stomach with a pH of 1 what will happen in terms of non ionized form of weak acids and ionized weak bases.

Answer 28

Both of them will dominant but weak acids will be more readily absorbed than weak bases.

Question 29

We're are weak bases mostly absorbed

Answer 29

In the intestines with pH of 7

Question 30

Weak acids can also be readily absorbed from the intestines than from the stomach despite their greater ionization because

Answer 30

Because of the increased surface area

Question 31

What is the use of the Henderson - Hasselbalch equation

Answer 31

It's useful for estimating the PH of a buffer solution and finding the equilibrium PH in an acid -base reaction

Question 32

What do the weak acids (HA) donate and what do the weak bases accept

Answer 32

The weak acids donate a proton (H+) to form anion (A-) while weak bases accept a proton to form cations

Question 34

How are drugs distributed to the body organs and tissues into the interstitial fluid and cells

Answer 34

Through circulation and diffusion

Question 35

A good number of drugs are not uniformly distributed throughout total body water.other drugs are restricted to the extracellular fluid or........

Answer 35

Plasma concentration

Question 36

Drugs with......... easily diffuse into cells through membranes

Answer 36

Sufficient lipid solubility

Question 37

Drugs can also be actually transported into cells eg ....

Answer 37

Drugs transportation into hepatic cells were they may undergo biotransformation

Question 39

Drugs distribution is some way opposed by a number of ATp driven efflux pumps known as ..

Answer 39

ABC transporters ( ABC being an acronym of ATP binding cassette)

Question 40

The most notable or widely studied ABC is the p- Glycoprotein(pgp) also called....

Answer 40

Permeability Glycoprotein. Which is expressed on the luminal side of intestines, brain capillaries.

Question 41

What do phg excludes from various tissues act as

Answer 41

They act as a detoxifying mechanism but can lead to therapeutic challenges like the exclusion of cancer drugs from tumours which can cause chemotherapeutic drug resistance

Question 42

Drugs like...........inhibit pgp and hence help in increasing tissue levels of these drugs and thereby augmenting their pharmacological effects

Answer 42

Amiodarone , erythromycin, propranolol

Question 45

Organ blood flow is one of the factors that affect drug distribution which tissues experience the rapid drug distribution and thus enabling a rapid onset of action

Answer 45

High perfused tissues like the brain, heart,liver and kidney

Question 46

Which tissues experience a low drug distribution.

Answer 46

Less perfused tissues like the skin, bones and skeletal muscles

Question 48

Almost all drugs are reversibly bound to plasma proteins primarily albumin while others are what...

Answer 48

Lipoprotein, glycoprotein and B-globulins

Question 49

The extent of binding depends on what

Answer 49

Drugs affinity for the protein binding site which ranges from 10 -99% of the plasma concentration

Question 50

Plasma protein binding is saturable and a drug can be displaced by another drug with what

Answer 50

Higher affinity for such sites

Question 51

Molecular size is one of the factors that affect drug distribution . what kind of drugs does it affect and give an example.

Answer 51

It's affects the distribution of extremely large molecules eg antic

Question 56

What is drug biotransformation or metabolism

Answer 56

This is an enzyme catalyzed conversation of drugs to their metabolites

Question 57

Biotransformation mostly takes place in the liver but the metabolizing enzymes are also found were

Answer 57

They are also found in other tissues like the gut , brain, kidney, lungs and skin

Question 58

Which two processes are responsible for the decline of plasma drug concentration over time

Answer 58

Biotransformation and excretion

Question 59

Which process are involved I. Drug elimination

Answer 59

Biotransformation and excretion

Question 60

Define clearance

Answer 60

Is a measure of the rate of elimination of the drug

Question 61

What is the role of drug biotransformation

Answer 61

The fundamental role is to inactive drugs and other foreign compounds that Can harm the body It's also acts as the natural detoxifying process

Question 62

Why is it that drug metabolites are usually excreted by the kidney s

Answer 62

Because drug metabolites are usually more water soluble than their parent drugs Note some drug metabolites are are active while others are inactive

Question 63

What is conjunction

Answer 63

This is the process by which drugs undergo attachment to polar groups Note a general rule suggest that most of these conjugated drugs are inactive expect with a few exceptions

Question 64

Give an example of a active drug that can be converted to their active metabolites

Answer 64

Sedatives drugs like deazepam

Question 65

How do drugs absorbed through the gut reach the liver

Answer 65

It's reaches the liver through the hepatic portal vein before entering the systemic circulation.

Question 66

What type of reaction does phase l include or involve

Answer 66

It's involves oxidative, hydrolytic, deamination and reductive reactions

Question 67

What is a prodrug

Answer 67

Theses are pharmaceutically formulated inactive compounds which are biotransformed into active metabolites.

Question 69

Drug biotransformation is dividend into two phrases each carried out by unique sets of metabolic enzymes these phases are what

Answer 69

Phase l and phase II

Question 70

In which phase is drugs metabolites mostly active and in which phase is drug mostly inactive.

Answer 70

In phase I drug metabolites are pharmacologically active and mostly in phase ll drug metabolites are inactive.

Question 71

Which phase l reaction of biotransformation is catalyzed by enzymes isolated by the microsomal fraction of the liver

Answer 71

Oxidative reaction

Question 72

What happens at phase l

Answer 72

In phase l ezymetic reactions create or unmask a chemical group required for phase for phase l l

Question 73

What is the microsomal cytoplasm p450 ( Cyp) mono- oxygenase system

Answer 73

This is a family of enzymes that catalyzes the biotransformation of drugs with a wide range of chemical structure

Question 74

Give an example of a prodrug

Answer 74

Enalapril

Question 75

CYP exist in different families as what

Answer 75

CYP1,CYP2, CYP3 which are likely related by gene duplication

Question 76

How is each family divided

Answer 76

It's divided into subfamilies with a related homologous protein sequence of which CYP3A catalyzes more than half of microsomal drug oxidation

Question 77

There are a number of drugs that affect the metabolism of drugs by either....

Answer 77

Inducing or inhibiting the CyP enzymes

Question 78

What do CYP450 enzyme inducers do

Answer 78

They cause the increase in the enzyme secretion

Question 79

What happens when the CYP inducers are given concomitantly with another drug whose metabolism is dependent on the CYP enzyme.

Answer 79

The other drug is metabolized at an increased rate.which may affect the therapeutic effect because of the reduced bioavailability of the other drug

Question 80

Give examples of cyp enzyme inducers

Answer 80

Rifampicin, phenobarbitone, carbamazepine, phenytoin (RPPC)

Question 81

What do CYP450 enzyme inhibitors do

Answer 81

They cause the reduction in the secretion of the enzyme

Question 82

What happens when the secretion of enzymes is reduced

Answer 82

It's leads to the accumulation of the other drug whose metabolism is dependent on the CYP enzyme because of reduced clearance.which will eventually lead to toxicity

Question 83

Give examples of cyp enzyme inhibitors

Answer 83

Erythromycin, ciprofloxacin, cimetidine .

Question 84

Alcohol is metabolized to aldehyde by what...

Answer 84

Alcohol dehydrogenase

Question 85

Caffeine and theophylline a bronchodilator are metabolized by what enzyme

Answer 85

Xanthine oxidase

Question 87

Amides and esters are hydrolyzed by a variety of enzymes including

Answer 87

Cholinesterase which inactivate choline esters

Question 88

A drug esmolol is used for what

Answer 88

The treatment of tachycardia

Question 89

Which vasodilator undergoes reductive hydrolysis catalyzed by glutathione organic nitrate reductase

Answer 89

Nitroglycerine

Question 90

Chloramphenicol,an antimicrobial agent is metabolized by what

Answer 90

By nitro reductase with also an involvement of CYP enzymes

Question 91

Which reaction is less common compared to oxidative and hydrolytic reactions

Answer 91

Reductive reactions