Pharmacokinetis MCQ's

19 Questions | Total Attempts: 536

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Pharmacokinetis MCQ

Different drugs have different effect on a patient and the effect take some time to get notice or get the desired outcome. Just how well do you understand the movement of a drug within the body? Take up the pharmacokinetics MCQ`s below and expand your understanding on the topic. All the best!


Questions and Answers
  • 1. 
    A patient suffering from manic depressive psychosis is on lithium therapy. The graph shows plasma concentration of the drug at different time intervals, Routine weekly therapeutic drug monitoring reveals that plasma lithium level is 8 ng/L which is highly toxic. Renal function is normal. How long should you withhold lithium in order to reach a safer yet probably therapeutic level of 2 ng/L?
    • A. 

      32 hours

    • B. 

      24 hours

    • C. 

      48 hours

    • D. 

      64 hours

    • E. 

      72 hours

  • 2. 
    1. Mr. X and Mr.Y, who have identical body weight, underwent tonsillectomy and post operatively received ciprofloxacin (an antibiotic). This antibiotic is known to undergo 50% clearance through the liver and 50% clearance through the kidney. Liver and renal function tests were performed on both men. Mr. X's liver and kidneys were functioning at 100%.
    Y's liver was functioning at 1000/0 but his kidneys function was 50% of normal. Every 12 hours, 500mg of ciprofloxacin was given to Mr. X. If the drug is metabolized by the same pathways in both patients, which of the following maintenance regimens in Mr. Y would produce the same average concentration as observed with the Mr. X?
    • A. 

      500 mg every 8 hours

    • B. 

      500 mg every 12 hours

    • C. 

      250 mg every 12 hours

    • D. 

      375 mg every 12 hours

  • 3. 
    • A. 

      Weak Acid.................. 4..........................8

    • B. 

      Weak Acid...................8..........................8

    • C. 

      Weak Base...................5..........................9

    • D. 

      Weak Base...................8..........................7

  • 4. 
    • A. 

      18 minutes

    • B. 

      30 minutes

    • C. 

      36 minutes

    • D. 

      24 minutes

  • 5. 
    A urine sample was obtained from a 33-year-od man suspected of substance abuse and tested for the presence of drugs. The results showed the presence of morphine glucuronide. The glucuronide of morphine is formed by:
    • A. 

      Phase 1 reaction catalyzed by microsomal enzymes

    • B. 

      Phase 1 reaction catalyzed by non-microsomal enzymes

    • C. 

      Phase ll reaction catalyzed by microsomal enzymes

    • D. 

      Phase II reaction catalyzed by non-microsomal enzymes

  • 6. 
    The same dose of four different drugs was administered IV to the same lab animal on four different occasions. The following pharmacokinetic data were obtained: Drug Cpo (ng/m1) A 25 B 12  C 44 D 90 Which of the following drugs will have the lowest Vd?
    • A. 

      A

    • B. 

      B

    • C. 

      C

    • D. 

      D

  • 7. 
    A 62-year old hypertensive patient is admitted hospital. A single dose of an antihypertensive drug which has half life of 8 hours and volume of distribution of 25L/70kg was administered orally. How many hours will it take to eliminate approximately 93% of the given drug from the body?
    • A. 

      2 hours

    • B. 

      8 hours

    • C. 

      16 hours

    • D. 

      32 hours

  • 8. 
    A 3-year-old child is brought to the emergency department having just ingested a large overdose of Amphetamine, a weak base. It is capable of entering most tissues, including the brain. On physical examination, the heart rate is 100 beats/min, blood pressure 140/100 mm Hg, and respiratory rate 20 breaths/minute. Which of the following statements reaarding the treatment of this patient is most correct?
    • A. 

      Gastric absorption of amphetamine can be inhibited by administration of sodium bicarbonate

    • B. 

      Gastric absorption of amphetamine can be inhibited by administration of ammonium chloride

    • C. 

      Urinary excretion of amphetamine can be accelerated by administration of sodium bicarbonate

    • D. 

      Urinary excretion of amphetamine can be accelerated by administration of ammonium chloride

  • 9. 
    In phase-1 clinical of trials, a new antibiotic is being tested in an adult person. The antibiotic has the following pharmacokinetic parameters: Clearance = 100 L/hour Vd 50L t1/2 = 3 hours If the drug has to be administered intravenously what dose should be given to quickly obtain a plasma concentration of 10mg/L?
    • A. 

      500mg

    • B. 

      100mg

    • C. 

      25mg

    • D. 

      5mg

  • 10. 
    The pKa of salicylic acid is 3.0. What percentage of the drug is likely to be excreted in the urine at a pH of 5?
    • A. 

      50%

    • B. 

      99%

    • C. 

      1%

    • D. 

      0.1%

    • E. 

      76%

    • F. 

      9%

  • 11. 
    On the assumption that only lipid diffusion determines the rate of absorption of the listed drugs, which of the following drugs will be most rapidly absorbed, when given by oral route (assume a pH of 7.5 in the small intestine)?:
    • A. 

      Naproxen (acid, pKa = 5.0)

    • B. 

      Pyrimethamine (base, pKa = 7.0)

    • C. 

      Ampicillin (acid, pKa = 2.5)

    • D. 

      Diazepam (base, pKa = 3.0)

    • E. 

      Ethosuximide (acid, pKa = 9.3)

  • 12. 
    A 67-year-old man is suffering from terminal cancer and the physician decides to start a morphine treatment PO. Morphine has an oral bioavailability of about 24% and a volume of distribution of 230 L. Effective plasma concentration for the analgesic effect are about 55 mcg/L. The initiat oral dose for this patient should be in which of the following ranges?
    • A. 

      10-20 mg

    • B. 

      30-40 mg

    • C. 

      50-70 mg

    • D. 

      80-100 mg

    • E. 

      110-130 mg

  • 13. 
    A 2 mg/Kg dose of a new drug was given IV to a voluntary subject (weight 80 Kg) during a phase 1 clinical trial. The drug followed a first order, one compartment model kinetics, and had a volume of distribution of 1 L./Kg. Which of the following was most likely the concentration of the drug in plasma (in mg/L) at zero time?
    • A. 

      4.0

    • B. 

      2.0

    • C. 

      0.5

    • D. 

      1.6

    • E. 

      16

    • F. 

      1.0

  • 14. 
    A 68-year-old man, with chronic renal insufficiency, was diagnosed with acute osteomyelitis and a vancomycin treatment was planned. About 80% of vancomycin is excreted by the kidney and the renal clearance of the drug is about 90 ml/min in a normal person. in that patient, vancomycin concentration after a test dose was 4 mg/ml in the urine and 0.11 mg/ml in the plasma. The urine flow of the patient was 0.5 ml/min. Assuming that the standard therapeutic dosage of vancomycin is 500 mg per day, which of the fo!lowing would be (in mg per day) the appropriate initial dosage for that patient?
    • A. 

      50

    • B. 

      100

    • C. 

      200

    • D. 

      300

    • E. 

      400

  • 15. 
    A 10 mg dose of a new drug was giver IV to voluntary subjects in a phase I clinical trial. The volume of distribution of the drug turned out to be 80 liters. Which of the following would have been (in liters) the volume of distribution of the drug, if the administered dose were 20 mg?
    • A. 

      40

    • B. 

      80

    • C. 

      240

    • D. 

      160

    • E. 

      120

  • 16. 
    A drug has a total clearance of 1200 ml/min and an hepatic clearance of 400 mL/min; 25% of the administered drug is eliminated unchanged in the urine. Which of the following would be the clearance (in mL/min) due to organs other than liver and kidney?
    • A. 

      50

    • B. 

      200

    • C. 

      350

    • D. 

      500

    • E. 

      750

  • 17. 
    A 32-year-old cocaine addict was brought to the hospital 3 hours after self-injecting (IV) an unknown dose of cocaine. At admission the plasma level of cocaine was 1.25 mg/L. Pharmacokinetics data for Cocaine include: Vd . 140 L, Clearance. 134 L/h, half-life. 1 hour. Which of the following was most likely the injected dose of cocaine?
    • A. 

      2.5g

    • B. 

      1.4g

    • C. 

      0.4g

    • D. 

      0.8g

    • E. 

      1.8g

    • F. 

      3.2g

  • 18. 
    A drug which follows first-order kinetics was given by IV infusion at a rate of 5 mg/min. The resulting mean steady-state plasma concentration was 50 mcg/mL. Which of the following would be (in mL/min) the total clearance of the drug?
    • A. 

      50

    • B. 

      1000

    • C. 

      200

    • D. 

      500

    • E. 

      100

    • F. 

      2000

    • G. 

      10

  • 19. 
    A 53-year-old patient with an impending pulmonary edema received (IV) a bolus dose of furosemide. The drug has a volume of distribution of about 8 liters and a half-life of 1.5 hours. After 3 hours the plasma concentration of furosemide was 1.25 mcg/ml. Which of the following was the dose of the drug (in mg)  given to the patient?
    • A. 

      20

    • B. 

      60

    • C. 

      50

    • D. 

      80

    • E. 

      40

    • F. 

      10

    • G. 

      100

    • H. 

      200