11. Pharmacokinetics I

Question 1

A new drug weak base drug is made with a pK 3.5. What percentage of the given dose of the drug will be in the lipid soluble form at a stomach pH of 2.5.

A.  99%
B. 1%
C. 10%
D.90%
E.95%

RFA

Answer 1

Ans. C 10% pH-Pk=-1 log A/Ha .1 so A= 10% and HA=90% and since in is a weak base it is soluble in the unprotonated form so 10%

Question 2

A patient is taking a basic drug to help treat his indigestion. What is true of drugs with this quality?

A.  Excreted faster in alkaline urine
B. Binds to a1-acid glycoprotein
C. Is more lipid soluble in the protonated form
D. Binds to plasma albumin 
E. Aspirin would be classified as one

RFA

Answer 2

Ans. B.- Weak acids bind to a1-acid glycoprotein

A. Basic drugs are excreted faster in acidic urine, acidic drugs faster in alkaline

C. Basic drugs are more soluble in the unprotonated form

D. Acids bind to plasma albumin

E. Aspirin is an example of a weak acid

Question 3

Two drugs are examined by a pharmacist side by side. Drug A is taken orally, has a concentration of 10 micrograms, and a dosage of 15 mg. Drug B has the same active ingredients, taken orally, has a concentration of 10 micrograms, and a dosage of 10 mg. Are the drugs A and B bioequivalent?

A. Yes
B. No
C. I don’t know
D. I want pizza

SZ

Answer 3

Ans. B No

Bioequivalence requires that drug have same active ingredients, identical concentrations, identical doses, and same route of administration.

Question 4

A patient in the ED is begging for IV dilaudid. The extend of absorption of the IV drug is 95. You decide to administer the patient a 64 mg oral dose instead. The extent of absorption for the oral dose is 75. Determine the bioavailability of dilaudid.

A. 79
B. 126
C. 98
D. 100
E. 67 

SZ

Answer 4

Ans. A 79

Bioavailability = AUC oral/AUC IV x100

Question 5

You need to perform an eye exam on a patient. You give them tropicamide to dilate the eye. What route of administration does the drug use? (MG)

A. IV
B. Intramuscular
C. Topical
D. Transdermal

Answer 5

C. Topical

Cyclopentolate uses topical on eye also

Question 6

A 16 year old female presents to the ED unconcious. She was discovered by her parents in the kitchen, with an empty bottle of pills in her hand. She has overdosed on a weak acid in an attempt to end her life. What do you give her to force her kidneys to excrete the drug into the urine? (MG)

A. Sodium bicarbonate
B. Ammonium chloride
C. Sodium benzoate
D. Calcium dihydroxlsulfate

Answer 6

A. Sodium bicarbonate

Want to make urine alkaline to keep drug OUT of the liposoluble phase and prevent it from being reabsorbed from renal tubules