Deck 6: Chapter 6: Pharmacokinetics and Drug Absorption: Understanding Drug Permeation, Distribution, and Elimination

Question 1

All of the following about passive absorption is true EXCEPT:

A) The driving force is concentration gradient
B) Does not involve a carrier
C) The process is saturable
D) The process shows a low structural specificity
E) The process is suitable for lipid soluble drugs

Answer 1

The process is saturable

Question 2

All of the following are general mechanisms of drug permeation Except

A) Aqueous diffusion
B) Aqueous hydrolysis
C) Lipid diffusion
D) Pinocytosis or endocytosis
E) Special carrier transport

Answer 2

Aqueous hydrolysis

Question 3

The following factor(s) influencing drug absorption:

A) Blood flow to the absorption site
B) Total surface area available for absorption
C) Contact time at the absorption surface
D) All of the above
E) None of the above

Answer 3

All of the above

Question 4

First pass effect is:

A) The amount of the drug destroyed by stomach acidity after oral administration of drugs for the first time.
B) The amount of the drug passed with stool after oral administration.
C) Amount of drug lost due to hepatic metabolism during drug absorption for the first time after oral administration
D) Amount of drug that is eliminated by the liver by hepatic artery.
E) The amount of drug that bypass the Cirrhosed liver after oral administration through portosystemic anastomosis.

Question 5

What does the term "bioavailability" mean?

A) Plasma protein binding degree of substance
B) Permeability through the brain-blood barrier
C) Fraction of an uncharged drug reaching the systemic circulation following any route administration
D) Amount of a substance in urine relative to the initial doze

Question 6

Factor(s) that influence bioavailability of drugs:

A) First-pass hepatic metabolism
B) Solubility of the drug
C) Chemical instability in GIT
D) Nature of the drug formulation re
E) All of the above

Question 7

What is the proportion of nonionized form of week base (pka = 9.4)when put in a media ( pH = 7.4 )

A) 99%
B) 1%
C) 0.1%
D) 50%

Question 8

Which of the following acids has the highest degree of ionization in an aqueous solution?

A) Aspirin pKa = 3.5
B) Indomethacin pKa = 4.5
C) Warfarin pKa = 5.1
D) Ibuprofen pKa = 5.2
E) Phenobarbital pKa = 7.4

Question 9

The excretion of a weakly acidic drug generally is more rapid in alkaline urine than in acidic urine. This process occurs because

A) A weak acid in alkaline media will exist primarily in its ionized form, which cannot be reabsorbed easily
B) A weak acid in alkaline media will exist in its lipophilic form, which cannot be reabsorbed easily.
C) All drugs are excreted more rapidly in an alkaline urine.

Question 10

Passive diffusion doesn't depend on,

A) Permeability
B) Thickness
C) Concentration difference
D) Number of transporters

Question 11

The following factor(s) determine drug distribution:

A) Blood flow
B) Capillary permeability
C) Drug structure
D) All of the above

Question 12

Most of the drugs are distributed homogeneously

Question 13

The volume of distribution for a drug that is completely retained in the vascular compartment would be.

A) High
B) Low
C) Unchanged
D) Cannot be determined

Question 14

A patient is treated with a Drug A, which has a high affinity for Albumin and is administered in amount that don't exceed the binding capacity of Albumin. A second drug B also has a high affinity for albumin but is administered in amounts that are 100 time the binding capacity of albumin. What happens after administration of Drug B?

A) High tissue Conc. for Drug A
B) Low tissue Conc. For Drug A
C) Low vd of Drug A
D) Low half life of Drug A
E) Addition of more Drug A significantly alters the serum conc. of unbound Drug B

Question 15

All of the following factors may increase the volume of distribution EXCEPT:

A) Extremely lipid soluble drugs
B) Blood tissue barriers
C) Drug-drug interactions
D) None of the above

Question 16

All of the following statements related to the binding of drugs by plasma proteins are correct EXCEPT?

A) Bound drug is unable to diffuse into tissue until it becomes unbound.
B) A drug that is bound by plasma proteins will have a smaller apparent volume of distribution than if it were not bound.
C) Displacement of the bound drug by another drug can increase the effects of a given dosage of the first drug.
D) Acidic drugs are bound mostly to plasma albumin.
E) Bound drug is the pharmacologically active part of the drug

Question 17

All of the following about free drugs (unbound drags) in plasma are correct EXCEPT:

A) Only free drugs can distribute to peripheral tissues
B) Only free drugs can pass through glomerular filtration
C) Only free drugs become available for hepatic metabolism
D) Highly bound drugs (98% bound) have clinically significant drug-drug interactions with other drugs through displacement from binding sites on plasma protein
E) Basic drugs bind with acidic binding sites on plasma globulins while acidic drugs bind with basic binding sites on plasma albumin

Question 18

A patient with an edema would have an increased volume of distribution if

A) The patient was taking a hydrophobic drug
B) The patient was taking a hydrophilic drug
C) An edema always causes an increase in Vd
D) An edema always causes an decrease in Vd

Question 19

What would be the expected distribution of Digoxin in the case of odema?

A) Higher than expected
B) Lower Vd than expected
C) None of above

Question 20

What is the reason of complicated penetration of some drugs through brainblood barrier?

A) Incredibly high lipid solubility of a drug
B) Meningitis
C) Absence of pores in the brain capillary endothelium
D) High endocytosis degree in a brain capillary

Question 21

All of the following conditions tend to increase the patients response to drugs EXCEPT:

A) Congestive cardiac failure.
B) Hepatic cirrhosis.
C) Hyperthyroidism.
D) Hypothyroidism
E) Hyperalbuminemia

Question 22

The P-glycoprotein is a multidrug transmembrane transporter protein that transports medications across cell membranes. Functions of this protein include

A) Pumping drugs into the urine for excretion
B) Transport of drugs into liver hepatocytes
C) Transport of drugs into fetal circulation for fetal treatment
D) Transport of drugs from the intestinal lumen to the circulation
E) Transport of drugs from the bloodstream into brain cells

Question 23

Researcher is studying the bioavailability of commonly used antimuscarinics to treat irritable bowel syndrome. Medication A is administered in a 100 mg daily dose orally and 60 mg of the drug is absorbed from the gastrointestinal tract unchanged. Thus, the bioavailability of Medication A is

A) 40%
B) 60%
C) 70%
D) 80%
E) 90%

Question 24

A 27-year-old female with vulvovaginal candidiasis is given a one-time 100 mg dose of oral fluconazole. She has no other pertinent medical problems and takes no prescription medications. Administration of the medication results in a peak plasma concentration of 20 mg/L. What is the apparent volume of drug distribution?

A) 0.5 L
B) 1 L
C) 3 L
D) 5 L
E) 50 L

Question 25

Pick out the right statement:

A) High molecular weight drugs get excreted in Urine
B) Lipid-soluble drugs with low molecular weight get excreted in biles
C) Antibiotics may undergoes active secretion

Question 26

The most rapid eliminated drugs are those with glomerular filtration rate and active secretion but aren't passively reabsorbed:

A) .....
B) .......

Question 27

Binding of a drug to plasma proteins will tend to:

A) Decrease half-life.
B) Decrease its rate of glomerular filtration.
C) Increase its rate of biotransformation.
D) Increase its concentration in the plasma
E) Increase its pharmacological activity

Question 28

If a drug is eliminated by first order kinetics

A) A constant amount of the drug will be eliminated per unit time
B) Its clearance value will remain constant
C) Its elimination half-life will increase with dose
D) It will be completely eliminated from the body in 2 x half-life period

Question 29

Disappearance of most drugs from the plasma follows first order kinetics, which means that:

A) The rate of disappearance is independent of the amount of drug left at any time
B) The rate of disappearance is proportional to the amount of drug left at any time
C) The disposition mechanisms are saturated
D) The drug is rapidly metabolized
E) The rate of disappearance is proportional to clearance rate

Question 30

Drugs showing zero-order kinetics of elimination

A) Are more common than showing first-order kinetics
B) Shows exponential decrease with time
C) Have a t1/2 independent of dose
D) Show a plot of drug concentration versus time that is linear
E) Shows a constant fraction of the drug eliminated per unit time

Question 31

If a drug is not metabolized, is bound 50% to plasma protein, and has a renal clearance of 400 mL/min in man, the mode of excretion must be:

A) Glomerular filtration
B) Filtration and reabsorption
C) Tubular secretion
D) Filtration and secretion
E) Excretion by extrarenal route

Question 32

Which of the following results in a doubling of steady-state conc. of the drug

A) Doubling the rate of infusion
B) Maintaining the rate of infusion but doubling the loading dose
C) Doubling the rate of infusion and doubling the concentration of the infused drug.
D) Tripling the rate of infusion

Question 33

A student studying pharmacology is a member of a team that is conducting research related to the elimination of multiple anticoagulant medications. His duty as a member of the team is to collect serum M samples of the subjects every 4 hours and send them for analysis of serum drug levels. He is also supposed to collect, document and analyze the data. For one of the subjects, he notices that the subject is eliminating 0.5 mg of the drug every 4 hours. Which of the following anticoagulants did this patient most likely consume?

A) Aspirin
B) Enoxaparin
C) Dabigatran
D) Fondaparinux
E) Apixaban

Question 34

A drug with a half life of 8 hours is administered by continuous intravenous infusion. How long will it take to reach 90% of its final steady-state level?

A) 12 hours
B) 18 hours
C) 25 hours
D) 30 hours
E) 40 hours

Question 35

A patient receives a single dose of antibiotics following a prostate needle biopsy. He takes 500 mg of ciprofloxacin immediately after completion of the procedure. The half-life of the medication is 8 h. At approximately how many halflives will it take for 90% of the drug to be excreted from the body?

A) 1.0
B) 2.0
C) 3.0
D) 3.3
E) 5

Question 36

Pharmacokinetic characteristics of propranolol include Vd = 300 L/70 kg, CL = 700 mL/min, and oral bioavailability f = 0.25. What is the dose needed to achieve a plasma level equivalent to a steady-state level of 20 ?g/L?

A) 4 mg
B) 8 mg
C) 12 mg
D) 24 mg
E) 48 mg

Question 37

A doctor write in a prescription ( Take 1 Capsule (3mg) every 6 hours ) and you know the t1/2 of the drug = 3 hours, then, what's the maximal amount of the drug that would accumulate in Plasma?:

A) 4mg
B) 3mg
C) 7mg
D) 6mg

Question 38

Normally, acetaminophen has a Vd = 70L and C1 = 350 mL/min. If acetaminophen was administered to a patient with 50% renal function, what parameter would differ from normal?

A) Loading dose would be higher
B) Maintenance dose would be lower
C) t ½ would be higher
D) Vd would be 35L
E) Cl would be 700 mL/min

Question 39

A drug with elimination rate of 5mg/h had a 5mg/L serum level. If the urine concentration of the drug is 30mg/L and urine flow rate is 10mg/L what is the renal clearance?

A) 10L/h
B) 20 L/h
C) 40 L/h
D) 60 L/h

Question 40

A solution Verapamil is administered to the portal vein of the isolated perfused liver of a rat at a concentration of 8.9 mg/L. After 5 minutes, the concentration that is measured at the hepatic vein is 2.99 mg/L and the hepatic blood flow is 1050 mL/min. What is the hepatic extraction rate (ERH) of verapamil in this model/Hepatic clearance respectively

A) 0.5286/687.2 mL/min
B) 0.7563/656.5 mL/min
C) 1.3345/732.7 mL/min
D) 0.2123/504.4 mL/min

Question 41

A 28-year-old man with seborrheic dermatitis is prescribed a topical corticosteroid crème by his dermatologist in hopes of alleviating the chronic rash and erythema on the cheeks. Which of the following steps is most critical to achieve a therapeutic drug concentration in plasma?

A) Absorption
B) Distribution
C) Elimination
D) Glycosylation
E) Metabolism

Question 42

The route of drug administration is determined by

A) Water solubility of the drug
B) Lipid solubility of the drug
C) Ionization of the drug
D) Desirability of rapid onset of action of the drug
E) All of the above

Question 43

All of the following about oral drug absorption is true EXCEPT:

A) The most variable route of administration
B) The most complicated of administration
C) Duodenum is the major site of entry to the systemic circulation
D) Most drugs absorbed from the gastrointestinal tract enter directly the systemic circulation
E) First-pass metabolism by the liver limits the efficacy of many drugs.

Question 44

Correct statements listing characteristics of a particular route of drug administration include all of the following EXCEPT:

A) Intravenous administration provides a rapid response
B) Intramuscular administration requires a sterile technique
C) Inhalation provides slow access to the general circulation
D) Subcutaneous administration may cause local irritation

Question 45

Intravenous injections are more suitable for oily solutions:

Question 46

Which of the following routes have the highest bioavailability?

A) Oral
B) Rectal
C) SC
D) More than one answer

Question 47

Which of the following is disadvantage of IM administration?

A) Larger volumes can be used
B) Can affect lab test
C) Painful
D) A and C
E) B and C

Question 48

A 79-year-old man with end-stage Alzheimer's disease and dysphagia is taking multiple medications. Physical examination reveals xerostomia and a limited gag reflex. Which of the following routes of medication administration would provide the lowest serum drug concentration?

A) Enteral
B) Intramuscular
C) Intrathecal
D) Intravenous
E) Transdermal

Question 49

A 15-year-old boy who has diabetes and is insulin dependent is brought to the emergency department after collapsing at a baseball game. His blood sugar is 463 mg/dL by finger stick. Which of the following routes of administration would be most efficacious for medications to bring the blood sugar down?

A) Intramuscular
B) Intravenous
C) Sublingual
D) Subcutaneous

Question 50

In an anaesthetized dog, repeated intravenous injection of ephedrine shows the phenomenon of

A) Anaphylaxis
B) Tachyphylaxis
C) Idiosyncrasy
D) Drug resistance

Question 51

Which of the following therapeutic systems provides continuous, unattended, controlled drug input for a long period without gastrointestinal or hepatic drug inactivation prior to systemic circulation ?

A) Parenteral
B) Oral
C) Transdermal
D) All the above
E) None of the above

Question 52

Volatile drug may be best administered by:

A) Oral route
B) Inhalation
C) Sublingual route
D) Intrathecal route
E) Rectal route

Question 53

The main route of administration of a drug to produce a local effect is

A) Topical
B) Oral
C) Parenteral

Question 54

When a drug has a low therapeutic index, that drug should be

A) Used mostly orally
B) Used mostly intravenously
C) Considered a potentially toxic substance
D) Given only in submilligram doses

Question 55

All of the following statements are true EXCEPT:

A) Biotransformation of drugs in the body usually yields products that diffuse across renal tubular membranes less readily than the parent compounds.
B) Biotransformation reactions often yield products that are inactive pharmacologically.
C) Biotransformation reactions can yield products that are pharmacologically more active than the parent compound
D) Biotransformation reactions can yield products that are more lipophilic than the parent compound.
E) In some cases, biotransformation reactions enhance the toxicity of chemicals introduced into the body.

Question 56

All of the about reaction of drug metabolism is correct EXCEPT:

A) Water soluble drugs must first be metabolized in the liver
B) Phase 1 reaction function to convert lipophilic molecules into lipophobic molecules
C) Phase 1 reactions involved in drug metabolism catalyzed by the p450 system
D) Phase II include conjugation with endogenous substances

Question 57

Which of the following is entirely microsomal?

A) Acetylation and methylation of substances
B) Transformation of substances due to oxidation, reduction or hydrolysis…
C) Glucuronide formation
D) The use of Ziegler's enzyme
E) nothing

Question 58

All of the following about drug metabolism is true EXCEPT:

A) Pro-drugs must be metabolized to their active forms
B) First-order kinetics metabolism means that a constant amount of drug is metabolized per unit of time
C) Zero-order kinetics metabolism the enzyme is saturable
D) Ethanol follows zero order kinetics
E) None of the above

Question 59

Metabolic transformation and conjugation usually results in an increase of a substance biological activity:

Question 60

The addition of glucuronic Acid to drug

A) Lowers its water solubility.
B) Usually leads to inactivation of the drug
C) Is an example of Phase 1 reaction.
D) Occurs at the same rate in adults and newborns.
E) Involves cytochrome P450

Question 61

In case of liver disorders accompanied by a decline in microsomal enzyme activity, the duration of action of some drugs is:

A) Decreased
B) Enlarged
C) Remained unchanged
D) Changed insignificantly

Question 62

An elder man was brought up to the emergency room for suspicion of Liver cirrhosis. His wife mentioned him having severe headache throughout the day, making swallow up to 10 analgesic analgesic pills which she forgot the name of. What was the drug?

A) NAISD
B) Isoniazid
C) Acetaminophen
D) Halothane
E) None of the above

Question 63

One of the following drugs undergoes metabolism just to be more effective and is the less-active form of morphine,

A) Levodopa
B) Enalapril
C) Codeine
D) Minoxidil

Question 64

One of the following drugs can be used to reduce blood pressure in patients with Chronic Renal Insufficiency:

A) Aspirin
B) Enalapril
C) Digoxin
D) Atenolol

Question 65

CYT3A4 heavily contributes to what part of Liver metabolism?

A) Conjugation
B) Oxidation
C) Reduction
D) Hydrolysis

Question 66

All of the following is true EXCEPT:

A) UGT is the predominant Phase 2 enzyme for lifetime
B) Glutathione conjugates are excreted in bile or are converted to mercapturic acid
C) For the sake of drugs' inactivation, Methyltransferase may be used.
D) N-acetylated cysteine conjugates appear in urine by Active transport.

Question 67

Which drug after undergoing Acyl glucuronidation Become insanely reactive?

A) Ibuprofen
B) Paracetamol
C) NASIDs
D) A+B
E) A+C

Question 68

Paracetamol undergoes both Acetylation and Glucuronidation but without GSH the alternative CYT-450 dependent pathway causes hepatoxicity.

Question 69

Which of the following drugs may inhibit the hepatic microsomal P450 and contains Imidazole group

A) Cimetidine
B) Ethanol
C) Phenobarbital
D) Procainamide
E) Rifampin

Question 70

Antiepileptic drug, leads to tolerance to drug ,after 2-3 weeks it will not activate its metabolism and it is needed to increase the dose and ultimately inhibits the hepatic microsomal enzymes.

A) Ethanol
B) St. John's wort
C) Ritonavir
D) Byproduct of tobacco
E) Carbamazepine

Question 71

Which one of the statements regarding microsomal enzymes is not correct

A) They lack specificity
B) Capable of metabolizing substances of different structure
C) Only catalyze reaction of compounds which are lipid insoluble
D) All the above

Question 72

An 82-year-old man is admitted to the hospital after a new diagnosis of multiple myeloma. Treatment is initiated with bortezomib, lenalidomide, and dexamethasone. Intravenous morphine is administered at regular intervals for control of bone pain. Two days later his creatinine increases from 1.0 to 2.3 mg/dL. He is noted to be lethargic with respirations of 8/min (normal >12). Naloxone is administered and he becomes more alert with increased respirations. Which of the following may explain his response to morphine?

A) Decreased bioavailability
B) Increased volume of distribution
C) Accumulation of morphine metabolites
D) Inhibition of liver P450 enzymes
E) Downregulation of opioid receptors

Question 73

A 5-year-old boy is brought to the emergency room by his mother. One hour ago, he ingested an unknown quantity of one of her prescription medications. Serum testing shows the boy's drug level is 5 mg/dL. The drug is known to have a half life of 1 hour, a volume of distribution of 150 ml, a bioavailability of 50%, and follow first-order elimination kinetics. Which of the following doses did the boy ingest?

A) 15mg
B) 20mg
C) 30mg
D) 40mg
E) 60mg

Question 74

A 45-year-old man is started on an intravenous neuroleptic drug for treatment of seizures. His weight is 75 kg. The drug has a volume of distribution of 0.5 L/kg. If the desired serum concentration is 20 mg/L, what is the appropriate loading dose?

A) 37.5mg
B) 100mg
C) 375mg
D) 750mg
E) 1500mg

Question 75

A 45-year-old man is started on an intravenous neuroleptic drug for treatment of seizures in the hospital. He achieves a steady state plasma drug concentration of 20 mg/L. After no seizure activity for 48 hours, plans are made to discharge him on an oral form of his seizure drug. The drug's clearance rate is 0.25 L/hr and bioavailability is 50%. Which of the following is an appropriate oral dosing regimen?

A) 10mg once per day
B) 20mg twice per day
C) 120mg twice per day
D) 1000me twice per day
E) 2000mg once per day

Question 76

You are currently employed as a clinical researcher working on clinical trials of a new drug to be used for the treatment of Parkinson's disease. Currently, you have already determined the safe clinical dose of the drug in a healthy patient. You are in the phase of drug development where the drug is studied in patients with the target disease to determine its efficacy. Which of the following phases is this new drug currently in?

A) Phase 1
B) Phase 2
C) Phase 3
D) Phase 4

Question 77

A 49-year-old man with diabetes mellitus takes subcutaneous insulin for his insulin-dependent diabetes mellitus. He takes 4 U of regular insulin every 12 h to maintain his blood sugar in the range of 80 to 140 mg/dL. This route of administration allows for absorption of insulin by which of the following processes?

A) active transport
B) Facilitated transport
C) Osmosis
D) Passive transport
E) Simple diffusion

Question 78

An 80-year-old male nursing home resident is hospitalized on a morphine drip to control pain for his terminal metastatic pancreatic cancer. Morphine undergoes phase I and phase II metabolism in the liver as well as being metabolized by other enzymes. Some of these metabolic reactions decrease with age. Which of the following metabolic reactions is likely still intact in this patient?

A) Glucuronidation
B) Hydrolysis
C) Oxidation
D) Reduction
E) Unmasking of a functional group

Question 79

A 44-year-old black male is brought to the emergency department with 6 h of worsening lethargy and confusion. Past medical history is significant for easy bruising, 3 months of bone pain, and frequent pneumococcal infections. Labs were ordered, revealing serum calcium of 17 mg/dL (normal: 9.0 to 10.5 mg/dL). To rapidly lower his serum calcium, you administer calcitonin. However, calcitonin alone is insufficient because it is known to rapidly and suddenly lose its effectiveness within 2 to 3 days of repeated dosing. For this reason, a bisphosphonate, which take 2 to 3 days to become effective, is added simultaneously. What is the term for the rapid decrease in response to calcitonin?

A) Anaphylaxis
B) Prophylaxis
C) Tachyphylaxis
D) Tolerance

Question 80

Regarding the use of a daily baby aspirin, oral fiber supplements, and a daily "water" pill in an 89-year-old man with hypertension and coronary artery disease, which of the following statements is true regarding pharmacology in the elderly patient?

A) Coexisting disease states are unlikely to produce additive impairment
B) Elderly patients are less sensitive to drug effects
C) Elderly patients are less sensitive to drug side effects
D) Elimination of drugs becomes impaired with age
E) Responses to compensate for drug accumulation are satisfactory