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.