WorksheetsQuiz 1. PK: Key concepts for Beginners
Total questions: 20
Worksheet time: 15mins
A drug with high lipid solubility and small molecular size is administered orally. Through which mechanism is it most likely to be absorbed into the bloodstream?
Active transport
Facilitated diffusion
Passive diffusion
Endocytosis
A 35-year-old male is administered a drug known to have poor absorption in the gastrointestinal tract. Which route of administration would be the most appropriate to bypass the first-pass effect?
Oral
Rectal
Intravenous
Sublingual
Which of the following factors is most likely to decrease the oral bioavailability of a drug?
High solubility in lipids
Slow gastric emptying
Extensive first-pass metabolism
Small molecular size
Drugs that are confined primarily to the plasma compartment are likely to have:
A high volume of distribution
A low volume of distribution
A moderate volume of distribution
No measurable volume of distribution
A drug has a volume of distribution of 0.08 L/Kg and is primarily distributed in the plasma.
Which of the following characteristics is most likely true about this drug?
Lipophilic and small
Hydrophilic and large
Highly protein-bound
Hydrophilic, large, and highly protein-bound
A patient with liver cirrhosis is given a drug that is highly protein-bound under normal conditions.
Due to their condition, the patient has reduced albumin levels.
How will this affect the free drug concentration in plasma?
Decrease
Remain unchanged
Increase
Be eliminated faster
A patient with liver disease is likely to experience:
Increased metabolism of drugs
Decreased metabolism of drugs
Normal drug metabolism
Enhanced elimination of drugs
Which genetic factor can influence Phase I metabolism?
Polymorphism in CYP450 enzymes
Decreased renal clearance
Protein-binding variability
Increased capillary permeability
What happens to a prodrug during metabolism?
It is excreted without any change
It is converted to its inactive form
It is converted to its active form
It bypasses the liver
Which statement is true regarding Phase I and Phase II metabolism?
Drugs must go through Phase I before Phase II
Drugs can bypass Phase I and directly undergo Phase II
Phase II metabolism occurs exclusively in the mitochondria
Phase I metabolism makes drugs less polar and lipid-soluble
How does protein binding affect drug filtration in the kidneys?
It increases filtration
It decreases filtration
It has no effect on filtration
It only affects secretion
What happens during reabsorption in the kidneys?
Drugs are filtered into the Bowman’s capsule
Drugs are actively transported into the urine
Drugs passively diffuse back into the bloodstream
Drugs are metabolised in the nephron
Which property makes a drug more likely to be reabsorbed in the kidneys?
Polar, water-soluble and large
Non-polar, lipid-soluble and small
Large and protein-bound
Negatively charged
What is the main characteristic of first-order elimination kinetics?
A constant amount of drug is eliminated per unit time
The rate of elimination is independent of drug concentration
A constant fraction of drug is eliminated per unit time
The drug is eliminated only via the liver
In zero-order kinetics, why does the rate of elimination not increase with drug concentration?
Because the drug is protein-bound
Because the enzymes are saturated at Vmax
Because the drug has low bioavailability
Because the drug is metabolised in the kidneys
Which type of elimination produces an exponential decay curve when drug concentration is plotted over time?
First-order kinetics
Zero-order kinetics
Mixed-order kinetics
Saturable kinetics
A drug is eliminated at a rate of 20 mg/h, regardless of its plasma concentration.
What type of elimination kinetics does this describe?
First-order kinetics
Zero-order kinetics
Mixed-order kinetics
Second-order kinetics
Which of the following is not one of the three key considerations when designing a dosage regimen?
The molecular weight of the drug
The dose of the drug
The dosing interval
The route of administration
True or False: Elimination of a drug begins only after its plasma concentration has peaked
True
False
Why does it usually take 5 half-lives to reach steady-state?
Because drug absorption is slow
Because 95% of the steady-state level is reached by then, and further accumulation is minimal
Because that’s when drug toxicity is highest
Because dosing intervals increase after 5 doses
