Half Life (Drug Calculations Practice Problems - Part 6)

Questions we discussed are:

00:00 - A new developed medication ..... drug eliminated by first-order kinetics. From the presented graph, what is the half-life of new medication?
A. 0.3 h
B. 1 h
C. 2 h
D. 3 h
E. 4 h
F. 6 h

01:40 - A new drug X was administered during phase I .... The table illustrates the plasma concentration of X as a function of time after the initial IV loading dose. What is the half-life (in hours) of drug X?
A. 1
B. 2
C. 4
D. 5
E. 9

02:59 - A drug X has an apparent volume of distribution of 50 L. It is known that Drug X undergoes zero-order elimination at a rate of 2 mg/hour. If a patient has plasma concentration of Drug X of 4 mg/L, how long will it take (in hours) for the plasma concentration to decrease 50%?
A. 1
B. 2
C. 10
D. 15
E. 25
F. 35
G. 50

04:58 - A 58-year-old man ..... Physician decided to start antimicrobial therapy for this patient and 240 mg of intravenous gentamicin was administered. It is known that gentamicin has an apparent volume of distribution of 30L, a half-life of 4 hours, and demonstrates first-order elimination kinetics. Which of the following is the most likely serum drug concentration just before the next dose 8 hours later?
A. 0.5 mg/L
B. 1 mg/L
C. 1.5 mg/L
D. 2 mg/L
E. 2.5 mg/L
F. 3 mg/L

06:30 - A new Drug X is undergoing Phase I clinical trials. From previous participants it was known that the half-life of this drug is 9 hours. During IV injection to new participants, one healthy volunteer has a severe adverse reaction to this medication, and the drug was discontinued immediately. How long will it take until the plasma drug level drops to approximately 6% of the initial steady state level in this individual with adverse reaction?
A. 9 hours
B. 18 hours
C. 27 hours
D. 36 hours
E. 45 hours
F. 54 hours

07:00 - A 30-year-old male .... Assuming that the half-life of gentamicin is 3 hours in this patient, what percentage of the initial dose of the drug will most likely remain in his body 6 hours later?
A. 12.5
B. 25
C. 37.5
D. 50
E. 75
F. 87.5

07:29 - A 60-year-old man .....He is given 500 mg of antimicrobial drug X via IV infusion. Several minutes after infusion, the serum concentration of drug X is 12.5 mg/L. 2 hours later the serum concentration was measured at the level of 10 mg/L. Assuming the drug X has first order elimination kinetics, which of the following will be the serum concentration of drug X (in mg/L) in the next 2 hours?
A. 6
B. 6.5
C. 7
D. 7.5
E. 8
F. 8.5
G. 9

12:51 - A 78-year-old male .... He is administered 100 mg of a drug X. Shortly after administration, serum level of the drug X is 20 mg/dL. One hour after that, serum drug concentration was 16 mg/dL. If the drug follows zero order elimination kinetics, what will the serum concentration be in another hour?
A. 15.0 mg/dL
B. 14.2 mg/dL
C. 12.8 mg/dL
D. 12.0 mg/dL
E. 8.5 mg/dL
F. 8 mg/dL
G. 4 mg/dL

14:19 - Drugs A and B are similar in that they are not undergo extensive metabolism in tissues, they are not bound to plasma or tissue proteins, and not secreted or reabsorbed by the renal tubule. Both drugs A and B also have same clearance rate, but they have different apparent volumes of distribution: 10L and 30L, respectively. If the elimination half-life for A is 60 minutes, what is the most approximate elimination half-life for B?
A. 30 minutes
B. 60 minutes
C. 90 minutes
D. 120 minutes
E. 180 minutes
F. 240 minutes

16:57 - During phase I clinical trial, the pharmacokinetics of a new drug X was studied in healthy volunteers. The apparent volume of distribution and renal clearance of new medication determined in the patient are 40 L and 2.0 L/hour, respectively. Which of the following is the most likely half-life of the drug in this volunteer?
A. 2 hours
B. 6 hours
C. 14 hours
D. 20 hours
E. 28 hours

17:37 - Mr. J. is a 42-year-old male who owns his own construction company. Mr. J. has a past medical history of major depressive disorder and now presents to the mental health clinic. He has been successfully treated with supportive therapy and paroxetine 30 mg once daily. He has stopped taking the medication on several instances. Within 3 days, the patient calls her physician and complains of intense anxiety, insomnia, restless legs, diarrhea, dizziness, and what she describes as “brain zaps”. Instead of the paroxetine, fluoxetine was immediately started at 20 mg daily, and the patient’s symptoms abated slowly over the next month. If fluoxetine has a volume of distribution of 30 L and a clearance rate of 0.15 L/h, which of the following is the approximate half-life of fluoxetine?
A. 3.2 days
B. 4.5 days
C. 8.3 days
D. 5.8 days

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Видео Half Life (Drug Calculations Practice Problems - Part 6) канала Oleksii Hliebov