Verified Solutions
Which of the following does NOT influence the degree to which a drug moves by passive diffusion
across membranes?
a. the lipophilicity of a drug
b. the degree of gastric absorption
c. the proportion of drug that is charged
d. the concentration gradient between the two compartments ANS ANS: B
Which of the following characteristics of a drug in a solution contributes to its passive diffusion
through membranes (choose all that apply)?
a. high lipophilicity
b. its positive ionic charge
c. high hydrophilicity
d. small molecular size ANS ANS: A, D
Penetration of high molecular weight drugs through membranes is most dependent on which of the
following processes?
a. phagocytosis
b. active transport
c. passive diffusion
d. enzyme inhibition ANS ANS: B
Which one of the following is a true statement with regard to pH-dependent ionization?
a. Acids ionize best in an acidic medium.
b. For bases to ionize, the medium must be acidic.
c. An acid is a proton acceptor, whereas a base is a proton donor.
d. When an acid gives up positively charged ions, the acid becomes more basic. ANS ANS: B
,Based on body compartment pH, a weak acid such as acetaminophen (Tylenol) or ampicillin
(Amoxil) will be absorbed best at which one of the following sites?
a. lung
b. stomach (pH ~ 2)
c. subcutaneous fat
d. small intestine (pH ~ 5.5 -7.5) ANS ANS: B
Which of the following would be better absorbed by means of an intramuscular (IM) injection?
a. water soluble drug
b. protein bound drug
c. lipid soluble drug
d. drugs metabolized by first pass processes ANS ANS: A
Which of the following is true regarding a drug that binds extensively to plasma proteins?
a. is readily eliminated by the kidney
b. only unbound drug exits the vasculature
c. has a shorter half-life than a weakly bound drug
d. is likely to have few drug interactions with drugs that are also extensively bound
to plasma proteins. ANS ANS: A
A drug that is highly extracted by the liver (hepatic first pass effect) will have which one of the
following?
a. long half-life (t1/2)
b. low renal clearance
c. low oral bioavailability
d. high volume of distribution (Vd) ANS ANS: C
Genetic differences in drug CYP450 enzymes may lead to all of the following except:
a. increased adverse effects
,b. increased drug toxicity
c. increased drug interactions
d. increased rate of absorption in the gut ANS ANS: D
Why are polar groups added to lipid soluble drugs by hepatic enzymes during Phase I and Phase II
reactions?
a. to produce slower absorption and a longer half-life
b. to increase the concentration in the plasma compartment after oral administration
c. to prevent passive reabsorption and promote renal elimination
d. both b and c ANS ANS: C
Which one of the following statements is true about cytochrome P450 enzymes?
a. carry out functionalization reactions (phase I reactions)
b. are more active on lipid soluble drugs
c. individual differences may influence drug metabolism
d. all of the above ANS ANS; D
If drug A inhibits the cytochrome P450 enzyme system, which one of the following effects will
occur?
a. decrease in the half-life (t1/2) of drug A
b. decrease the hepatic clearance of related drugs
c. increase covalent bonding of related drugs to the enzyme
d. increase in the half-life (t1/2) of other drugs metabolized by the same enzyme ANS ANS: D
If drug B induces the cytochrome P450 enzyme system, which one of the following effects will
occur?
a. increase in the half-life (t1/2) of drug B
b. increase covalent bonding of related drugs to the enzyme
c. decrease the hepatic clearance of related drugs
d. decrease in the half-life (t1/2) of other drugs metabolized by the same enzyme ANS ANS: D
, Acidification of the urine by high doses of Vitamin C (ascorbic acid) may result in:
a. better elimination of aspirin, an acidic drug, due to ion trapping
b. better elimination of meperidine (Demerol), a basic drug, due to ion trapping
c. altered concentration gradient and faster absorption of aspirin, an acidic drug
d. altered concentration gradient and faster absorption of meperidine (Demerol), a
basic drug ANS ANS: B
Which of the following processes is not associated with pharmacokinetics?
a. Efficacy
b. Bioavailability
c. Clearance rate (CL)
d. Volume of distribution (Vd) ANS ANS: A
The half-life (t1/2) of drug A is 4 hours. What is its predicted plasma concentration compared to its
initial concentration, eight hours after a single I.V. injection:
a. 1/2
b. 1/4
c. 1/8
d. 1/16 ANS ANS: B
Based on the degree of distribution, which one of the following drugs will reach the highest
concentration in the lung?
a. gentamicin (Vd = 18 L/70 kg)
b. aspirin (Vd = 11 L/70 kg)
c. amikacin (Vd = 19 L/70 kg)
d. theophylline (Vd = 35 L/70 kg) ANS ANS: D
Based on the degree of distribution, which one of the following drugs will reach the highest
concentration in the plasma?