Week 9 formative quiz Flashcards
Displacement of a drug from plasma protein results in reduced bioavailability of the drug
False – displacement from plasma proteins results in increased bioavailability, and can lead to toxicity
If a drug undergoes extensive firstpass metabolism it will have a lower bioavailability
True – first-pass metabolism refers to when drugs are metabolized (eg by the gut lumen, gut wall, liver, etc) before entering the systemic circulation
Prolongation of the half-life will increase plasma levels of a drug
True, as this means it takes a longer time for the drug to be cleared
There are 6 steps on the stages of change cycle. Patients must always enter at the pre- contemplation stage.
False. Patients can enter and exit at any stage on the cycle
Drugs must be bound to plasma proteins to be biologically active
False – only drugs that are not bound to protein are biologically active
Drug interactions are most likely to occur in patients receiving large numbers of drugs
True – the more drugs, the more potential for interaction
Drugs applied to the skin will not have a systemic effect
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.)
Phase 2 metabolism involves oxidation, reduction or hydrolysis
False – these reactions take place in Phase 1 metabolism. Phase 2 metabolism involves conjugation
Up to 3% of hospital deaths occur as a result of an adverse drug reaction
True – ADRs are a major cause of morbidity and mortality in hospitalised patients
Drug-drug interactions can be beneficial
True – we frequently use drugs in combination to treat a condition, to utilise the way they interact together
Drugs which are absorbed slowly will have a shorter time to peak concentration (Tmax)
False – rapid absorption leads to a shorter time to peak concentration (Tmax)
Time to peak concentration (Tmax) and peak concentration (Cmax) for a given drug remain constant regardless of route of administration
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.
All new drugs will undergo Phase 1 clinical trials.
False – Phase 1 trials, where drugs are given to healthy volunteers, are bypassed for some drugs, such as cancer chemotherapy
All drugs are standardized, so it never matters what brand you prescribe
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
Gentamicin is lipid-soluble.
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
Excretion of drugs mainly takes place in the liver
False – the majority of drug excretion takes place in the kidneys.
The hepatic (liver) metabolism of many drugs is increased in the elderly
False – it is decreased. This is one of the mechanisms by which the elderly are more prone to drug toxicity and adverse reactions
A p value less than 0.5 is considered statistically significant
False – a p value less than 0.05 is considered statistically significant
The oral bioavailability of a drug is the percentage of a drug which reaches the systemic circulation
True – this can be estimated from the area under the concentration-time curve for a drug (AUC)
Increasing the dose of a drug will mean peak concentration (Cmax) is reached more quickly
False – The concentration will be higher, but increasing the dose does not change time to Cmax
Phase 3 clinical trials are where the efficacy of a drug is determined.
True – this is when the drug is given to patients with the disease or condition that it is intended to treat.
Adverse drug reactions should be reported using the pink card reporting system
False – adverse drug reactions should be reported using the yellow card reporting system
Clearance is measured in mg/L
False – it is measured in ml/min, and is a theoretical volume from which a drug is completely removed over a period of time
Type C adverse drug reactions are the most common
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
Park run is an example of influencing health related behaviour at a community level
True. Other examples are community support groups such as AA and local smoking cessation clinics.
Drugs with a wide therapeutic range are more likely to be involved in harmful drug-drug interactions.
False – drugs with a narrow therapeutic range are more likely to be involved in harmful DDIs
Ionised compounds rapidly pass through lipid membranes
False – ionized compounds cannot pass through lipid membranes. The un-ionised form of a drug will equilibrate across lipid membranes
In randomised controlled trials assessment is always carried out by blinded observers
False – some RCTs are single-blinded, meaning only the patient is blinded
In randomised controlled trials a non-significant result in a trial means that the treatment is ineffective
False – it may mean the trial was insufficiently powered to detect a significant result
Only water-soluble substances can be excreted by the liver or kidneys
True – lipid-soluble substances will be reabsorbed and re-enter the bloodstream
The liver secretes about 3L of bile a day
False – the liver normally secretes about 1L of bile a day
Renal impairment shortens the half-life of a drug
False – renal impairment prolongs the half-life
A crossover study compares response to two different treatments in the same patient
True – patients are given first one treatment, then another, and results are compared
An advantage of giving a drug as a suspension is that the dose is very accurate
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
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.
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
Food can enhance the rate of absorption of some drugs
True – different drugs are affected differently by food – some are enhanced, some impaired, some are unaffected
The greater the apparent volume of distribution (Vd), the greater the ability of the drug to diffuse through lipid membranes
True – this reflects the ability of a drug to leave the bloodstream and enter cells and interstitial fluid.
Smokers require a lower dose of theophylline than non-smokers
False – Smoking induces the enzyme CYP1A2, which metabolises Theophylline, therefore smokers require a higher dose than non-smokers
Phase 4 clinical trials gather data on long-term safety of a new drug
True – this surveillance happens after a drug has been licensed for use
Drugs given intravenously are not absorbed
True – there is no requirement to absorb drugs which are given intravenously as they are administered directly into the plasma
Drugs given intravenously are not absorbed
True – there is no requirement to absorb drugs which are given intravenously as they are administered directly into the plasma
The volume of distribution of a drug is decreased if the drug has high protein binding
True – this is because highly protein-bound drugs will be held in the plasma
Sublingual administration avoids first-pass metabolism.
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
Conjugation of a drug or drug metabolite increases water solubility
True – this in turn allows the metabolised drug to be excreted in urine or bile
In randomised controlled trials the patients recruited must be suitable for any of the treatments.
True – as they are equally likely to receive any of the possible treatments
Enteric coating of a tablet can protect the drug from stomach acid
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)
Inhibition of the Cytochrome P450 system by drugs is much slower than induction
False – enzyme induction can take weeks. Enzyme inhibition can happen very quickly (i.e. hours).
An individual with low self-efficacy is more likely to achieve and maintain their goal
False. The higher an individual’s self-efficacy the more likely they are to maintain their goal
Drugs must have completed phase 4 clinical trials before they can be licensed for use
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
Drugs which are absorbed slowly will have a shorter time to peak concentration (Tmax)
False – rapid absorption leads to a shorter time to peak concentration (Tmax)
Time to peak concentration (Tmax) and peak concentration (Cmax) for a given drug remain constant regardless of route of administration.
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
A crossover study compares response to two different treatments in the same patien
True – patients are given first one treatment, then another, and results are compared
If a drug undergoes extensive firstpass metabolism it will have a lower bioavailability.
True – first-pass metabolism refers to when drugs are metabolized (eg by the gut lumen, gut wall, liver, etc) before entering the systemic circulation
