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Worksheets[Revision] Pharmacokinetics
Total questions: 60
Worksheet time: 31mins
Which statement about the process of drug discovery is true?
It only encompasses the non-clinical laboratory and animal testing.
It is the process which ascertains the effectiveness and safety of potential drug candidates.
It is the process by which therapeutic compounds are formulated into medicines.
It ensures there are no side-effects associated with the potential drug candidates
What are the protein structures called that are expressed within the cell membranes and interact with endogenous signalling molecules or some drugs to initiate an intracellular response?
Enzymes
Hormones
Ligands
Receptors
What are adverse drug reactions (ADRs)?
The synergistic effects that are seen when some drugs are administered concurrently.
Responses to increased drug doses required to achieve the same physiological outcome.
Unintended alternative physiological responses caused by the drug that cause harm to the patient.
Harmful chemical interactions between two drugs that are used to treat the same clinical symptoms.
In pharmacokinetics what does the acronym ADME stand for?
Absorption, Distribution, Metabolism, and Excretion
Administration, Differentiation, Metabolism, and Excretion
Absorption, Disintegration, Metabolism, and Efficacy
Administration, Distribution, Metabolism, and Efficacy
Which of the following is the correct definition of bioavailability?
Bioavailability describes the proportion of the drug administered that is metabolised very quickly and thus is not available to induce a physiological effect.
Bioavailability describes the ability of the administered drug metabolites to cause undesirable physiological effects.
Bioavailability is used to describe the fraction of the dose of drug administered that is present within the body and facilitates the desired physiological effects.
Bioavailability is the length of time an administered drug is present in the body and thus is available to cause a physiological effect.
Given the information shown in the figure below, which of the following statements is correct?
Drug A has the most appropriate pharmacodynamic properties of the three drugs shown as it reaches maximal efficacy within the therapeutic window.
Drug B has the most appropriate pharmacodynamic properties of the three drugs shown as a range of its plasma concentrations are within the therapeutic window.
Drug C has the most appropriate pharmacodynamic properties of the three drugs shown as non-toxic effects are achieved within the therapeutic window.
All three drugs have appropriate pharmacodynamic properties as they all achieve maximal physiological effects and have concentrations within the therapeutic window.
Which of the following statements best describes pharmacodynamics?
The study of how drugs reach their target in the body and how the levels of a drug in the blood are affected by absorption, distribution, metabolism and excretion.
The study of how drugs can be designed using molecular modelling based on a drug's pharmacophore.
The study of how a drug interacts with its target binding site at the molecular level.
The study of which functional groups are important in binding a drug to its target binding site and the identification of a pharmacophore.
Which of the following statements best describes pharmacokinetics?
The study of how drugs reach their target in the body and how the levels of a drug in the blood are affected by various factors.
The study of how drugs can be designed using molecular modelling based on a drug's pharmacophore.
The study of how a drug interacts with its target binding site at the molecular level.
The study of which functional groups are important in binding a drug to its target binding site and the identification of a pharmacophore.
Which of the following characteristics is detrimental to oral activity?
stability to digestive enzymes
susceptibility to metabolic enzymes
stability to stomach acids
solubility in both aqueous and fatty environments
Some orally active drugs do not obey the rule of five. For example, some drugs with molecular weights greater than 500 are found to be orally active. Which of the following mechanisms is the most likely reason for this?
transport by transport protein
passage through pores between the cells of the gut wall
pinocytosis
ion channels
Some orally active drugs do not obey the rule of five. For example, some highly polar drugs with a molecular weight less than 200 are found to be orally active. Which of the following mechanisms is the most likely reason for this?
transport by transport proteins
passage through pores between the cells of the gut wall
pinocytosis
ion channels
Which type of infection could be orally treated with a highly polar antibacterial agent?
brain infection
kidney infection
gut infection
lung infection
Which of the following statements is false regarding the blood-brain barrier?
The walls of the capillaries supplying the brain have tight fitting cells making it difficult for polar drugs to leave the capillaries.
The capillaries in the brain have a fatty coating making it more difficult for drugs to enter the brain.
The walls of the capillaries supplying the brain are made up of several layers of cells, which act as a barrier to the release of drugs.
Hydrophobic drugs pass through the blood brain barrier more easily than hydrophilic drugs.
Which of the following statements is the closest description of Phase I metabolism?
Reactions which add a polar molecule to a functional group already present on a drug or one of its metabolites.
Reactions which occur in the blood supply.
Reactions which add a polar functional group to a drug.
Reactions which occur in the gut wall.
Which of the following statements is the closest description of Phase II metabolism?
Reactions which add a polar molecule to a functional group already present on a drug or one of its metabolites.
Reactions which occur in the blood supply.
Reactions which add a polar functional group to a drug.
Reactions which occur in the gut wall.
The disadvantages of oral administration, except
least economical
drug taken orally may cause emesis
drug taken orally may be destroyed by gastric acidity
drug taken orally may be metabolized by gastrointestinal flora
drug taken orally may be inconsistently absorbed due to the presence of food
Two most important sites for drug elimination:
pulmonary and liver
liver and gastrointestinal tract
kidney and liver
skin and liver
pulmonary and kidney
Factor(s) which effect a drug's volume of distribution:
patient's gender and age
presence of disease
drug pKa
extent of drug-plasma protein binding
All of above
Drugs least likely to penetrate across membranes:
protein-bound drugs
charged drugs
neutral drugs
lipid drugs
Concerning parenteral drug administration:
less predictable compared to oral administration route
not acceptable for unconscious patients
rate of drug systemic absorption insensitive to drug solubility in interstitial fluid
rate of systemic drug absorption following parenteral administration depends on absorbing capillary membrane surface area
Factors associated with drug absorption that can result in incomplete absorption
drug hydrophilicity (opposite of lipophilicity)
drug instability in gastric acid
presence of food in the GI tract
drug-drug interactions
All of above
Consider the following information about drug X: D = 300 mg; T = 24 h; F = 0.70 (70% absorption);Vd = 40 L; half-life = 15 hours: What is the Css (concentration at steady-state) for drug X?
0.0462 ug/ml at 24 hours
4.7 ug/ml at 24 hours
2.4 ug/ml at 24 hours
6.76 ug/ml at 24 hours
4.73 mg/ml at 24 hours
The volume of distribution equals _________ divided by initial drug concentration:
clearance
initial drug concentration
half-life
dose
If a drug is poorly distributed to tissues, its apparent volume of distribution is probably:
large.
small.
For the body fluid compartments below, rank them from the lowest volume to the highest, in a typical 70-kg person.
Plasma < extracellular fluid < intracellular fluid < total body water
Extracellular fluid < intracellular fluid < plasma < total body water
Intracellular fluid < extracellular fluid < plasma < total body water
Total body water < plasma < intracellular fluid < extracellular fluid
The units for clearance are:
concentration/half-life
dose/volume.
half-life/dose
volume/time
With a drug that follows first-order elimination, the amount of drug eliminated per unit time:
remains constant while the fraction of drug eliminated decreases.
decreases while the fraction of drug eliminated remains constant.
To determine drug clearance, we must first determine whether a drug best fits a one- or two-compartment model.
True
False
Which of the following is not a mechanism for pharmacokinetic analysis?
Compartment analysis
Non compartment analysis
Physiologic modeling
Human model
Ocular administration involves the treatment of which area?
The skin
The eyes
The ears
The lungs
Nasal administration is commonly used for the relief of?
Headache
Cough
Sore throat
Congestion
Where is the site of administration for a dosage form that uses transdermal delivery?
The eyes
The lungs
Under the tongue
The skin
Intravenous, intramuscular and subcutaneous are all examples of which routes of administration?
Pulmonary administration
Parenteral administration
Otic administration
Ocular administration
Capsules normally fall into two main categories. Which are they?
Hard gelatin capsules and soft gelatin capsules
Hard gelatin capsules and layered capsules
Soft gelatin capsules and compressed capsules
Compressed and layered capsules
A tablet to treat a headache must first be dissolved in water before swallowing. Which one of the following best describes this type of tablet?
Modified release
Oral disintegrating
Effervescent
Buccal
Which of the following formulations would not be applicable to ocular administration?
Solution
Liniment
Suspension
Ointment
Which one of the following is not a characteristic of a zero-order drug decomposition reaction?
The rate of reaction is constant
The rate of reaction is independent of the concentration of any of the reactants
The half-life of the drug decomposition is directly proportional to the initial concentration of API.
The units of the rate constant (k) are time-1
When the results of a drug degradation study are plotted on a graph, a plot of the logarithm of the amount of API remaining against time gives a straight line. Which one of the following is true?
The units of the rate constant (k) are concentration-1 time-1
The reaction is zero-order
The half-life may be represented by t1/2 = 0.693/k
The half-life is directly related to the initial concentration of the reactant
Regarding zero-order reactions, which one of the following is true?
The half-life may be represented by the expression t0.5 = 0.693/k
The rate of degradation is independent of the concentration of the reactant(s)
A plot of the concentration remaining against time is a straight line with a gradient of 1/k
The units of the rate constant (k) are time-1
A drug solution decomposes via first-order kinetics with a rate constant, k, of 0.0077 days-1. What is the half-life of the drug in solution?
0.033 day
33 days
70 days
90 days
What is the best description of blood?
Sol
Foam
Solution
Aerosol
Which of the following is not a mechanism for the separation of a physically unstable suspension of magnesium hydroxide in water?
Flocculation
Aggregation
Ostwald ripening
Hydrolysis
Which of the following is a Phase 1 reaction?
Reduction
Acetylation
Glucuronidation
Methylation
The plasma drug concentration versus time curve for a drug eliminated by zero order kinetics is linear.
True
False
Drug metabolism is the process that converts chemicals into less polar metabolites so that they are more difficult to excrete.
True
False
A characteristic of drugs eliminated by zero order kinetic processes is that the half life is not constant.
True
False
Mrs Baker was prescribed medicine X at a dose of 20mg three times a day for the first time last month. The usual dosage range is 30mg to 120mg daily. She tells you that her symptoms are not well controlled. She is not taking any other medication. Her prescriber asks your advice. What would you recommend?
Change the formulation to 60mg MR which she only needs to take once a day.
Use Therapeutic Drug Monitoring (TDM) to determine the actual level of drug in her blood.
Increase her dose so she is now taking 30mg three times a day.
Determine whether the patient has any difficulties taking the medicine.
Which of the following would be the most suitable course of action for a patient who refuses to take their prescribed medicine?
Explain to the patient that the medicine should be taken as prescribed in order to get the benefit of treatment and that the risk of harm from licensed medicines is very low.
Explore the reasons why they don't wish to take their medicine and explain the benefits and risks of taking the medicine and the implications of not taking the medicine to the patient.
Explore the reasons why they don't wish to take their medicine and try to convince them that the benefits of treatment outweigh the risks.
Explain the benefits of taking the medicine and the implications of not taking the medicine to the patient.
Which organs will make up the peripheral compartment?
Lungs
Liver
Kidneys
Pancreas
What is total systemic clearance?
Sum of clearance from kidney
Sum of clearance from kidney and liver
Sum of clearance form non-renal clearances
Sum of renal and non-renal clearances
What is the equation for clearance?
Elimination rate / plasma drug concentration
Plasma drug concentration/elimination rate
1 / Plasma drug concentration
1 / Elimination rate
Which one of the following is the principal organ for drug excretion?
Lungs
Liver
Kidneys
Sweat glands
In the following diagram which organ name should be in the place of ‘?’?
Small intestine
Large intestine
Liver
Kidney
Which compounds are excreted through the lungs?
Lipophilic
Gaseous
Liquid and hydrophilic
Solid less than 100 Dalton
The rate of urine flow influences the extent of reabsorption.
True
False
The enzyme system responsible for the metabolism of most drugs is
P-glycoprotein.
alkaline phosphatase.
creatine kinase.
cytochrome P-450.
Factors to be considered when prescribing the best drug dose of a patient include
age
gender
body weight
other concurrent disease states and drug therapies
all of the above
The drug biotransformation is a detoxification process.
True
False
Which of the following is the correct decreasing order of drug metabolism
Liver > lungs > kidneys > intestine > placenta > skin > adrenals
Liver > lungs > kidneys > intestine > adrenals > placenta > skin
Liver > kidneys > lungs > intestine > placenta > adrenals > skin
Liver > lungs > intestine > kidneys > placenta > adrenals > skin
Following are the Phase I reactions except
Oxidative reactions
Sulphide reactions
Hydrolytic reactions
Reductive reactions
