Week 9 formative quiz

Question 1

Displacement of a drug from plasma protein results in reduced bioavailability of the drug

Answer 1

False – displacement from plasma proteins results in increased bioavailability, and can lead to toxicity

Question 2

If a drug undergoes extensive firstpass metabolism it will have a lower bioavailability

Answer 2

True – first-pass metabolism refers to when drugs are metabolized (eg by the gut lumen, gut wall, liver, etc) before entering the systemic circulation

Question 3

Prolongation of the half-life will increase plasma levels of a drug

Answer 3

True, as this means it takes a longer time for the drug to be cleared

Question 4

There are 6 steps on the stages of change cycle. Patients must always enter at the pre- contemplation stage.

Answer 4

False. Patients can enter and exit at any stage on the cycle

Question 5

Drugs must be bound to plasma proteins to be biologically active

Answer 5

False – only drugs that are not bound to protein are biologically active

Question 6

Drug interactions are most likely to occur in patients receiving large numbers of drugs

Answer 6

True – the more drugs, the more potential for interaction

Question 7

Drugs applied to the skin will not have a systemic effect

Answer 7

False – drugs given topically (eg. Steroids) will still be absorbed and may have a systemic effect. Drugs can also be applied as patches, where the intention is for systemic activity (eg. A contraceptive patch or a nicotine patch.)

Question 8

Phase 2 metabolism involves oxidation, reduction or hydrolysis

Answer 8

False – these reactions take place in Phase 1 metabolism. Phase 2 metabolism involves conjugation

Question 9

Up to 3% of hospital deaths occur as a result of an adverse drug reaction

Answer 9

True – ADRs are a major cause of morbidity and mortality in hospitalised patients

Question 10

Drug-drug interactions can be beneficial

Answer 10

True – we frequently use drugs in combination to treat a condition, to utilise the way they interact together

Question 11

Drugs which are absorbed slowly will have a shorter time to peak concentration (Tmax)

Answer 11

False – rapid absorption leads to a shorter time to peak concentration (Tmax)

Question 12

Time to peak concentration (Tmax) and peak concentration (Cmax) for a given drug remain constant regardless of route of administration

Answer 12

False – the route of administration will impact Tmax and Cmax – for example, drugs given rectally are absorbed more slowly than when they are given orally.

Question 13

All new drugs will undergo Phase 1 clinical trials.

Answer 13

False – Phase 1 trials, where drugs are given to healthy volunteers, are bypassed for some drugs, such as cancer chemotherapy

Question 14

All drugs are standardized, so it never matters what brand you prescribe

Answer 14

False – once patients are established on certain modified-release therapies (eg. Lithium, anti-epileptic medications, and others) it is very important to continue using the same brand, otherwise you risk causing toxicity with different medicine compositions

Question 15

Gentamicin is lipid-soluble.

Answer 15

False – gentamicin is NOT lipid-soluble, and therefore cannot cross cell membranes, and is not absorbed. This is why it is generally given intravenously in clinical practice

Question 16

Excretion of drugs mainly takes place in the liver

Answer 16

False – the majority of drug excretion takes place in the kidneys.

Question 17

The hepatic (liver) metabolism of many drugs is increased in the elderly

Answer 17

False – it is decreased. This is one of the mechanisms by which the elderly are more prone to drug toxicity and adverse reactions

Question 18

A p value less than 0.5 is considered statistically significant

Answer 18

False – a p value less than 0.05 is considered statistically significant

Question 19

The oral bioavailability of a drug is the percentage of a drug which reaches the systemic circulation

Answer 19

True – this can be estimated from the area under the concentration-time curve for a drug (AUC)

Question 20

Increasing the dose of a drug will mean peak concentration (Cmax) is reached more quickly

Answer 20

False – The concentration will be higher, but increasing the dose does not change time to Cmax

Question 21

Phase 3 clinical trials are where the efficacy of a drug is determined.

Answer 21

True – this is when the drug is given to patients with the disease or condition that it is intended to treat.

Question 22

Adverse drug reactions should be reported using the pink card reporting system

Answer 22

False – adverse drug reactions should be reported using the yellow card reporting system

Question 23

Clearance is measured in mg/L

Answer 23

False – it is measured in ml/min, and is a theoretical volume from which a drug is completely removed over a period of time

Question 24

Type C adverse drug reactions are the most common

Answer 24

False – Type A (Augmented) ADRs are the most common, accounting for about 80%. These are predictable responses based on the known pharmacology of a drug

Question 25

Park run is an example of influencing health related behaviour at a community level

Answer 25

True. Other examples are community support groups such as AA and local smoking cessation clinics.

Question 26

Drugs with a wide therapeutic range are more likely to be involved in harmful drug-drug interactions.

Answer 26

False – drugs with a narrow therapeutic range are more likely to be involved in harmful DDIs

Question 27

Ionised compounds rapidly pass through lipid membranes

Answer 27

False – ionized compounds cannot pass through lipid membranes. The un-ionised form of a drug will equilibrate across lipid membranes

Question 28

In randomised controlled trials assessment is always carried out by blinded observers

Answer 28

False – some RCTs are single-blinded, meaning only the patient is blinded

Question 29

In randomised controlled trials a non-significant result in a trial means that the treatment is ineffective

Answer 29

False – it may mean the trial was insufficiently powered to detect a significant result

Question 30

Only water-soluble substances can be excreted by the liver or kidneys

Answer 30

True – lipid-soluble substances will be reabsorbed and re-enter the bloodstream

Question 31

The liver secretes about 3L of bile a day

Answer 31

False – the liver normally secretes about 1L of bile a day

Question 32

Renal impairment shortens the half-life of a drug

Answer 32

False – renal impairment prolongs the half-life

Question 33

A crossover study compares response to two different treatments in the same patient

Answer 33

True – patients are given first one treatment, then another, and results are compared

Question 34

An advantage of giving a drug as a suspension is that the dose is very accurate

Answer 34

False – suspensions are helpful for masking unpalatable, insoluble drugs for people who cannot swallow tablets or capsules. However, it can be difficult to achieve precise dosing. Tablets and capsules offer highly accurate dosing

Question 35

A 22 year old man is diagnosed with an eating disorder. He believes this stems from being bullied at school for being overweight. This is an example of a psychological factor influencing health.

Answer 35

True. This man’s previous experience of being bullied has had a detrimental impact on his mental health as a result of loss of confidence and self esteem. From bullying he has formed a negative image of his body resulting in the development of an eating disorder

Question 36

Food can enhance the rate of absorption of some drugs

Answer 36

True – different drugs are affected differently by food – some are enhanced, some impaired, some are unaffected

Question 37

The greater the apparent volume of distribution (Vd), the greater the ability of the drug to diffuse through lipid membranes

Answer 37

True – this reflects the ability of a drug to leave the bloodstream and enter cells and interstitial fluid.

Question 38

Smokers require a lower dose of theophylline than non-smokers

Answer 38

False – Smoking induces the enzyme CYP1A2, which metabolises Theophylline, therefore smokers require a higher dose than non-smokers

Question 39

Phase 4 clinical trials gather data on long-term safety of a new drug

Answer 39

True – this surveillance happens after a drug has been licensed for use

Question 40

Drugs given intravenously are not absorbed

Answer 40

True – there is no requirement to absorb drugs which are given intravenously as they are administered directly into the plasma

Question 41

Drugs given intravenously are not absorbed

Answer 41

True – there is no requirement to absorb drugs which are given intravenously as they are administered directly into the plasma

Question 42

The volume of distribution of a drug is decreased if the drug has high protein binding

Answer 42

True – this is because highly protein-bound drugs will be held in the plasma

Question 43

Sublingual administration avoids first-pass metabolism.

Answer 43

True – drugs (such as GTN) as absorbed directly from the oral mucosa into the systemic circulation, rather than undergoing first-pass metabolism in the gut

Question 44

Conjugation of a drug or drug metabolite increases water solubility

Answer 44

True – this in turn allows the metabolised drug to be excreted in urine or bile

Question 45

In randomised controlled trials the patients recruited must be suitable for any of the treatments.

Answer 45

True – as they are equally likely to receive any of the possible treatments

Question 46

Enteric coating of a tablet can protect the drug from stomach acid

Answer 46

True – it prevents tablet dissolution until it reaches the small intestine. This can be to protect the drug from stomach acid (eg. Omeprazole) or to protect the stomach from the drug (eg. Aspirin)

Question 47

Inhibition of the Cytochrome P450 system by drugs is much slower than induction

Answer 47

False – enzyme induction can take weeks. Enzyme inhibition can happen very quickly (i.e. hours).

Question 48

An individual with low self-efficacy is more likely to achieve and maintain their goal

Answer 48

False. The higher an individual’s self-efficacy the more likely they are to maintain their goal

Question 49

Drugs must have completed phase 4 clinical trials before they can be licensed for use

Answer 49

False – phase 4 clinical trials happen after the drug has been released. This is the ongoing surveillance stage of trialling a new drug, where long-term effects can be studied

Question 50

Drugs which are absorbed slowly will have a shorter time to peak concentration (Tmax)

Answer 50

False – rapid absorption leads to a shorter time to peak concentration (Tmax)

Question 51

Time to peak concentration (Tmax) and peak concentration (Cmax) for a given drug remain constant regardless of route of administration.

Answer 51

False – the route of administration will impact Tmax and Cmax – for example, drugs given rectally are absorbed more slowly than when they are given orally

Question 52

A crossover study compares response to two different treatments in the same patien

Answer 52

True – patients are given first one treatment, then another, and results are compared

Question 53

If a drug undergoes extensive firstpass metabolism it will have a lower bioavailability.

Answer 53

True – first-pass metabolism refers to when drugs are metabolized (eg by the gut lumen, gut wall, liver, etc) before entering the systemic circulation