Deck 3: Basic Principles of Pharmacology

Question 1

When drugs with sedative-hypnotic properties are administered chronically, what is the general effect on the P450 enzymes of the liver?

Answer 1

The rate of synthesis and levels of these enzymes will increase over time
Multiple choice questions.

Question 2

Describe the structural basis of the "blood-brain barrier" and list two characteristics of a drug that
e.g., like alcohol or lipid soluble or possess a structure allowing it to bind to a transport protein to be carried across these lipid membranes.

Answer 2

would allow it to pass through the BBB.
A .The cells comprising the capillaries that provide blood to the brain are tightly packed together, with minimal pores between them.In addition, parts of glial cells may cover the outside of the capillaries.These comprise a lipid barrier through which non-lipid soluble drugs cannot pass, unless the molecules are compatible with transport proteins that can carry them across these membranes.Thus, in order to penetrate this barrier, the molecule must be small and nonionized, e.g., like alcohol or lipid soluble or possess a structure allowing it to bind to a transport protein to be carried across these lipid membranes.

Question 3

Distinguish between a drug's "therapeutic index" and its "therapeutic window" (assuming the latter applies).

Answer 3

The therapeutic index, i.e., the ratio of a drug's LD50 to its ED50, is a gross measure of the drug's safety, whereas a drug's therapeutic window refers to the plasma concentration levels of the drug that are clinically effective, with levels below or above those levels being ineffective.

Question 4

The effects of a particular dose of a drug may differ significantly in young adults and elderly people, even if the dose is administered on a mg/kg basis.Give two reasons why this may occur.

Question 5

Assume that we have established a dose-response function for drowsiness induced by morphine and found that drowsiness occurred in 5% of people at 3 mg morphine, 20% at 6 mg morphine, 50% at 9 mg morphine, 85% at 12 mg morphine, and 100% at 15 mg morphine.We then find that three alcoholic beverages induce drowsiness in 5% of people.When we give different doses of morphine to people along with three alcoholic beverages, we find that now drowsiness occurs in 20% of people at 3 mg morphine, 50% of people at 6 mg morphine, 85% at 9 mg morphine, 100% at 12 mg morphine, and 100% at 15 mg morphine.What phenomenon are we most likely observing? Explain your answer.

Question 6

What is the "blood brain barrier"?

Question 7

Describe or define the following terms:
active placebo:

Question 8

Describe or define the following terms:
pharmacodynamics:

Question 9

Although heroin and morphine both exhibit analgesic properties, heroin is more potent that morphine when injected intravenously.What is the clinical relevance of this difference in potency between these two drugs?

Question 10

Assume that 30 mg of drug A puts 10% of people to sleep and that 100 mg of drug A puts 80% of people to sleep.Assume that drug B has no effect on sleep at any dose (except at lethal doses).If we give 100 mg of drug B along with 30 mg of drug A, we observe that the combination puts 50% of people to sleep.What phenomenon are we observing? Explain your answer.

Question 11

What are two reasons that the relative concentrations of a psychoactive drug may be lower in an
expectant mother's brain than in her fetus' brain?

Question 12

We often compare drugs in terms of their potency.Of what significance to therapeutics is the potency of a drug?

Question 13

What is the distinction between a drug's "clinical efficacy" and its "potency"?
e.g., the proportion of patients responding, the degree of response, the time it takes to respond, etc.Potency refers to the relative degree to which a drug produces a specific type of effect and the magnitude of the effect.The lower the dose necessary to produce that effect or magnitude of effect, the more potent the drug.(For example, clozapine [Clozaril] is considerably less potent than haloperidol [Haldol], because it requires considerably higher doses to control the symptoms of schizophrenia, but it has a greater clinical efficacy because it is more effective in reducing some of the core symptoms of the disease, is effective in a higher percentage of schizophrenic patients, and induces fewer of the types of side effects that lead to noncompliance with treatment.)

Question 14

Fred, a lipid-soluble drug molecule, has just been swallowed by a human.Trace Fred's likely routes through the body and describe what is likely to happen to Fred by the time he leaves the humans' body.

Question 15

Describe or define the following terms:
Effective dose (ED50):

Question 16

Distinguish between a drug's "efficacy" and its "potency".

Question 17

Assume that 30 mg of drug A puts 10% of people to sleep and that 100 mg of drug A puts 80% of people to sleep.Assume that drug B has no effect on sleep at any dose (except at lethal doses).If we give 100 mg of drug B along with 30 mg of drug A, we observe that the combination puts 50% of people to sleep.What phenomenon are we observing? Explain your answer.

Question 18

What is the primary function of the P450 enzymes in the liver?

Question 19

Mathematically, how does one determine a drug's "therapeutic index"?

Question 20

What does "first-pass metabolism" refer to?

Question 21

A drug's pharmacodynamics refers to its

A)movements through the body
B)biochemical and physiological effects and mechanisms of action
C)effects on behavior and mental processes
D)metabolic properties

Question 22

Drugs are most commonly administered

A)intravenously
B)orally
C)through inhalation
D)intramuscularly

Question 23

Drug metabolism refers to

A)the chemical changes that the drug goes through in the body
B)inactivation of the drug in the body
C)an increase in activity of the drug in the body
D)the activity of the drug at its site of action

Question 24

Excretion of drugs occurs most commonly through

A)the lungs
B)renal (i.e., involving the kidneys) excretion
C)hepatic (i.e., involving the liver) excretion
D)the feces

Question 25

A drug's therapeutic index is

A)a coarse measure of the relative safety of the drug
B)derived by dividing the drug's ED50 by its LD50
C)independent of the type of effect that is desired
D)all of the above

Question 26

The textbook suggests that morphine is more potent than aspirin because morphine

A)is more likely to induce side effects
B)is more lethal
C)requires lower doses for inducing analgesia
D)all of these

Question 27

Drugs A and B both reduce depression, but drug A is twice as potent as drug B.This difference in potency is

A)clinically important because one only needs to take half as much of drug A as drug B
B)not clinically important unless drug B's maximal response is less than that of drug A
C)not clinically important unless drug A's side effects are less disturbing than drug B's side effects
D)both b and c

Question 28

Teratogenic effects of drugs

A)have been observed to occur with the majority of drugs of abuse
B)have been observed to occur with some psychotropic drugs used in the treatment of mental disorders
C)may not be evidenced until years after birth
D)all of the above

Question 29

With chronic exposure, barbiturates and many other drugs with sedative properties have a tendency to ___________________ drug metabolizing enzymes.

A)have little effect on
B)increase production of
C)decrease production of
D)counteract the action of

Question 30

A shift in the dose-response function to the right indicates

A)an increase in potency
B)an increase in slope
C)a decrease in potency
D)a decrease in slope

Question 31

Which of the following drugs is most potent?

A)LSD
B)heroin
C)cocaine
D)none of these; it depends upon the specific effect one is looking for

Question 32

The "blood brain barrier" is primarily the result of

A)a number of astrocyte cells between the brain's extracellular space and the neurons
B)the brain capillaries' tightly packed endothelial cells and minimal pores
C)brain capillaries being separated from the blood vessels of the rest of the body
D)glial feet lining the brain's extracellular space

Question 33

Which of the following statements about a dose-response function is FALSE?

A)the function always shows the response magnitude increasing proportional to the dose
B)its form is always dependent upon the time since the drug was administered.
C)its form is often dependent upon the number of previous exposures to the drug.
D)its form is often dependent upon the interval between drug exposures.

Question 34

The therapeutic index is a

A)measure of relative safety of a drug
B)computed as a ratio of a drug's LD50 to its ED50
C)dependent upon the type of effect that is desired
D)all of the above

Question 35

Metabolism of drugs occurs primarily in the

A)plasma
B)kidneys
C)lungs
D)liver

Question 36

In a meaningful double-blind study

A)neither the investigators assessing the drug's effects nor the participants know which drug the participants received
B)placebo drugs are never administered
C)expectancy effects are not a factor
D)only the investigators assessing the drug's effects know what drug the participants received

Question 37

A major difference between oral and intramuscular drug administration is

A)variability in absorption
B)intensity of effect
C)time of onset of effect
D)all of these

Question 38

Choose the correct statement:

A)microsomal liver enzymes appear to have evolved to decrease the toxicity of drugs contained in plants
B)some drugs do not became psychoactive until they become ionized in the liver
C)unlike other enzymes, liver microsomal enzymes do not act on a wide variety of substances
D)the liver is the first place in which a drug can be rendered inactive

Question 39

Potency is inversely related to

A)the D2 enzyme.
B)the LD50.
C)the CP450.
D)the ED50.

Question 40

An enzyme

A)is used in an electrical action
B)is modified by a drug to produce an agonist
C)inhibits the formation of drugs
D)is a catalyst for a chemical reaction in the body

Question 41

As blood passes through the liver, drugs diffuse into the liver cells and are acted upon by

A)glycogen
B)leukocytes
C)cytochrome P450 enzymes
D)antigens

Question 42

Metabolism of drugs by the liver may involve

A)catabolism
B)anabolism
C)enhanced drug water solubility
D)all of these

Question 43

If a pregnant woman were to take a psychoactive drug, which of the following would be expected to exhibit the higher brain levels of the drug?

A)the pregnant woman
B)her fetus
C)the levels would be comparable in both
D)the levels would not be measurable

Question 44

Drug A is capable of reducing most of the symptoms of depression in 60% of depressed patients at 40 milligrams per day, but more than 40 milligrams per day doesn't produce any greater effect.Drug B is capable of reducing most of the symptoms of depression in 70% of depressed patients at 100 milligrams per day, but more than 100 milligrams per day doesn't produce any greater effect.Drug C is capable of reducing most of the symptoms of depression in 60% of depressed patients at 40 milligrams per day, but more than 40 milligrams per day produces severe side effects.Which of these drugs has the greatest clinical efficacy?

A)Drug A
B)Drug B
C)Drug C
D)They're all equal in clinical efficacy

Question 45

Antabuse (disulfiram) may be useful in the treatment of alcoholism because it

A)rapidly metabolizes alcohol into an inactive substance
B)reduces the ability of the body to inactivate a metabolite of alcohol which can make the person nauseated and throw up
C)decreases the activity of alcohol at it sites of action
D)all of the above

Question 46

Although rarely used in humans, injections of drugs into the abdominal cavity, called _____________, is commonly used with small animals such as rats.

A)intraperitoneal injection
B)intrathecal injection
C)sublingual administration
D)intraarterial injection

Question 47

A drug is generally considered to be any

A)chemical taken into the body
B)non-nutritive substance taken into the body
C)nonfood chemical that alters one or more biological activities in the body
D)chemical for which there are legal restrictions regarding its use

Question 48

If given in an amount proportional to body weight, a water-soluble drug (e.g., alcohol) is likely to achieve higher blood concentrations in

A)women than men
B)men than women
C)young people than elderly people

Question 49

The rate of excretion of certain acidic drugs can be enhanced by "alkalization" of the urine; also the rate of excretion for alkaline drugs can be enhanced by "acidification" of the urine.This is called

A)pH transduction
B)potentiation
C)metabolic reversal
D)ion trapping

Question 50

A drug's clinical efficacy is commonly determined on the basis of

A)the percentage of patients exhibiting symptom relief with the drug
B)the degree of symptom relief produced in patients given the drug
C)the time is takes for symptom relief to occur
D)all of the above

Question 51

The rate at which a drug is metabolized is proportional to the plasma concentration of the drug (in log units).This is referred to as ______________ kinetics.

A)zero order
B)first order
C)second order
D)third order

Question 52

When one is concerned with a drug's pharmacodynamics, one is chiefly concerned with

A)the behavioral effects of the drug
B)the mechanism of action of the drug
C)the long term consequences of exposure to the drug
D)the processes involved in the absorption, metabolization, and excretion of the drug

Question 53

Metabolism of drugs by the liver can result in

A)an increase in their potency
B)enhanced water solubility of the drug
C)enhanced ionization of the drug
D)all of the above

Question 54

The "first pass" metabolism effect will occur primarily with drugs administered

A)orally
B)rectally
C)subcutaneously
D)intravenously

Question 55

When a drug passes through the liver, the primary function of this organ is to

A)deflect the normal route of the drug
B)remove the drug from the bloodstream
C)bind the drug to albumin
D)change the drug's molecular structure so that it is easier to excrete

Question 56

If the rate at which a drug is metabolized is constant, i.e., is not proportional to the plasma concentration of the drug (in log units), it is referred to as _______________ kinetics.

A)zero order
B)first order
C)second order
D)third order

Question 57

In a proper double-blind experiment

A)the effects of an active drug treatment are compared with the effects of a placebo
B)neither the subjects nor the experimenters know what treatment the subjects receive until after all the drug tests are completed
C)subjects receive the active drug treatment and then are shifted to the placebo treatment without their being informed of the switch
D)only a and b above

Question 58

Alcohol is metabolized at a fairly constant rate regardless of the amount of alcohol ingested.This is referred to as _________________ kinetics.

A)third-order
B)second-order
C)first-order
D)zero-order

Question 59

When one is concerned with a drug's pharmacokinetics, one is chiefly concerned with

A)the behavioral effects of the drug
B)the mechanism of action of the drug
C)the long term consequences of exposure to the drug
D)the processes involved in the absorption, metabolization, and excretion of the drug
Chapter 3.Answers to multiple choice questions and

Question 60

The ED 50 for drugs A, B, C, and D are 10 mg, 50 mg, 100 mg, and 200 mg, respectively.The LD 50 for drugs A, B, C, and D are 100 mg, 150 mg, 500 mg, and 800 mg, respectively.Assuming the lethal dose response functions for all four drugs have the same slope, in general, which drug has the greatest margin of safety?

A)drug A
B)drug B
C)drug C
D)drug D

Question 61

Matching questions.In the space provided, indicate the letter corresponding to the most appropriate term that is defined or described below.
a.blood-brain barrier
b.agonist
c.enzyme
d.pharmacokinetics
e.efficacy
f.clinical efficacy
g.ion
i.metabolism
j.therapeutic index
k.pharmacodynamics
l.potency
m.physiological antagonism
1) _____ Study of the biochemical and physiological effects of drugs and their mechanisms of action.
2) _____ Refers specifically to the dose at which the effect occurs.
3) _____ A drug's relative margin of safety.
4) _____ Refers to the relative capability of an agent to activate a receptor after binding with the receptor.
5) ____ The processes involved in a drug's absorption, distribution, binding or localization in tissues, metabolic alterations, and excretion from the body.
6) _____ Structurally consisting of tightly packed endothelial cells of brain capillaries, surrounded by a very lipid sheath made up of extensions of "glial feet" from nearby astrocyte cells, which prevent non-lipid-soluble (most non-nutritive) substances from entering the central nervous system.
7) _____ A protein secreted by cells that acts as a catalyst to induce chemical changes in other substances, but which itself is unchanged in the process.