Lippincott Chapter 32: Drugs for Urologic Disorders Flashcards
32.1 Which of the following statements is CORRECT regard-
ing the mechanism of action of phosphodiesterase-5
(PDE-5) inhibitors?
A. PDE-5 inhibitors increase prostaglandin production.
B. PDE-5 inhibitors enhance the effect of nitric oxide.
C. PDE-5 inhibitors cause vasoconstriction of the
erection chamber.
D. PDE-5 inhibitors antagonize cyclic GMP.
Correct answer = B. PDE-5 inhibitors enhance the effect of
nitric oxide by preventing the breakdown of cGMP. PDE-5
inhibitors do not affect prostaglandin production. Although
blood is drawn to the erection chamber, PDE-5 inhibitors
allow for this via vasodilation, not vasoconstriction. PDE-5
inhibitors prevent the breakdown of cGMP but do not antag-
onize its action.
32.2 When selecting between the available PDE-5 inhib-
itors for treatment of ED, which of the following is an
important consideration?
A. Tadalafil has the shortest half-life of the PDE-5
inhibitors.
B. Sildenafil should be given with food to increase
absorption.
C. Vardenafil ODT doses are not equal to film-coated
vardenafil doses.
D. Avanafil should be taken at least 1 hour prior to
intercourse.
Correct answer = C. The ODT dosage form of vardenafil
provides a high systemic concentration of vardenafil, which
is higher than that provided by the film-coated tablets. As
such, the doses are not interchangeable. Tadalafil has the
longest half-life of all PDE-5 inhibitors. Food may delay
sildenafil absorption. Avanafil has the quickest onset of
action and may be taken 30 minutes prior to intercourse.
32.3 A patient who is taking a PDE-5 inhibitor for ED
is diagnosed with angina. Which of the following
antianginal medications would be of particular concern
in this patient?
A. Metoprolol.
B. Diltiazem.
C. Amlodipine.
D. Nitroglycerin.
Correct answer = D. Nitrates, when taken with PDE-5 inhibi-
tors, can cause life-threatening hypotension. While metopro-
lol, diltiazem, and amlodipine may all lower blood pressure,
the interaction with PDE-5 inhibitors is not relevant.
32.4 Which of the following BEST describes the mechanism
of action of alprostadil?
A. Alprostadil blocks cGMP.
B. Alprostadil blocks nitric oxide.
C. Alprostadil increases PDE-5.
D. Alprostadil increases cAMP.
Correct answer = D. Through an unknown mechanism,
alprostadil (a synthetic prostaglandin) increases levels of
cAMP, causing smooth muscle relaxation. Alprostadil does
not affect cGMP, nitric oxide, or PDE-5.
32.5 Alprostadil is administered locally. Which of the
following is CORRECT regarding local administration
of alprostadil?
A. Local administration of alprostadil allows for low
systemic absorption.
B. Local administration of alprostadil increases the
chance of drug interactions.
C. Local administration of alprostadil is accomplished
by way of a cream.
D. Local administration of alprostadil causes
changes in color vision.
Correct answer = A. Local administration of alprosta-
dil allows for minimal systemic absorption. This makes
alprostadil associated with few drug interactions. Alprostadil
is administered by injection or urethral suppository, not a
cream. Because there is little systemic absorption, and
alprostadil does not affect PDE-6, changes in color vision
are not likely.
32.6 Which of the following is the BEST description of the
mechanism of action of terazosin?
A. Terazosin blocks 5-α reductase.
B. Terazosin blocks α1A receptors.
C. Terazosin blocks PDE-5.
D. Terazosin blocks α1A and α1B receptors.
Correct answer = D. Terazosin blocks both the α1A and
α1B receptors. Terazosin does not affect 5-α reductase or
PDE-5
32.7 A patient is worried about starting terazosin because
he is very sensitive to side effects of medications.
Which of the following adverse effects would be most
expected in this patient?
A. Erectile dysfunction.
B. Gynecomastia.
C. Dizziness.
D. Vomiting.
Correct answer = C. Because of the α-blocking properties,
terazosin commonly causes dizziness (this may be related
to orthostatic hypotension). ED and gynecomastia would
be unexpected with α-blockers. While most any drug may
cause nausea and vomiting, terazosin is much more likely
to cause dizziness.
32.8 Which of the following is an important difference
between terazosin and tamsulosin?
A. Terazosin blocks α1A receptors, while tamsulosin
blocks α1A and α1B receptors.
B. Terazosin blocks α1A and α1B receptors, while
tamsulosin blocks α1A receptors.
C. Terazosin blocks 5-α reductase, while tamsulosin
blocks PDE-5.
D. Terazosin must be taken with food, while
tamsulosin can be taken on an empty stomach.
Correct answer = B. Tamsulosin is more selective for the
α1A receptor, found in the prostate. Terazosin blocks α1A;
however, terazosin also blocks α1B. Neither one blocks 5-α
reductase nor PDE-5. Tamsulosin should be taken with
food, while terazosin does not need to be taken with food.
32.9 Which of the following is CORRECT regarding
finasteride?
A. Finasteride is associated with significant
hypotension.
B. Finasteride is associated with birth defects.
C. Finasteride is effective within 2 weeks of initiation.
D. Finasteride is renally eliminated.
Correct answer = B. Because finasteride inhibits the con-
version of testosterone to its active form, it may cause
significant developmental defects in the male genitalia of
a developing fetus. As such, it is contraindicated in preg-
nancy. Unlike the α-blockers, the 5-α reductase inhibitors
are not associated with hypotension. Finasteride may take
up to 12 months before it is effective. Finally, finasteride is
metabolized via CYP450 and is not renally eliminated.
32.10 A 70-year-old male with BPH and an enlarged
prostate continues to have urinary symptoms after an
adequate trial of tamsulosin. Dutasteride is added to
his therapy. In addition to tamsulosin, he is also taking
hydrochlorothiazide, testosterone, and vardenafil as
needed prior to intercourse. Which of his medications
could have an interaction with dutasteride?
A. Hydrochlorothiazide.
B. Tamsulosin.
C. Testosterone.
D. Vardenafil.
Correct answer = C. Because dutasteride prevents the
conversion of testosterone to the more active form, DHT,
these medications have an interaction. Essentially, dutas -
teride prevents testosterone from “working.” Hydrochlo-
rothiazide does not interfere with the metabolism of
dutasteride, and dutasteride does not have any effect on
the blood pressure-lowering effects of hydrochlorothiazide.
Tamsulosin is appropriate in combination with a 5-α reduc-
tase inhibitor when the prostate is enlarged. Vardenafil is
only prescribed as needed, and the two drugs do not have
a pharmacokinetic interaction.
