Lippincott Chapter 30: Antihistamines Flashcards
30.1 A 43-year-old heavy machine operator complains of
seasonal allergies. Which one of the following medi-
cations would be most appropriate for management of
his allergy symptoms?
A. Cyclizine.
B. Doxylamine.
C. Hydroxyzine.
D. Fexofenadine.
Correct answer = D. The use of first-generation H1
antihista-
mines is contraindicated in the treatment of pilots and oth-
ers who must remain alert. Because of its lower potential to
induce drowsiness, fexofenadine may be recommended for
individuals working in jobs in which wakefulness is critical.
30.2 Which one of the following statements concerning
H1
antihistamines is correct?
A. Second-generation H1
antihistamines are
relatively free of adverse effects.
B. Because of the established long-term safety of
first-generation H1
antihistamines, they are the
first choice for allergic rhinitis.
C. The motor coordination involved in driving an
automobile is not affected by the use of first-
generation H1
antihistamines.
D. H1
antihistamines can be used in the treatment of
acute anaphylaxis.
E. Both first- and second-generation
H1
antihistamines readily penetrate the blood–
brain barrier.
Correct answer = A. Second-generation H1
antihistamines
are preferred over first-generation agents because they
are relatively free of adverse effects. Driving performance
is adversely affected by first-generation H1
antihistamines.
Epinephrine, not antihistamine, is an acceptable treatment
for acute anaphylaxis. Second-generation H1
antihistamines
penetrate the blood–brain barrier to a lesser degree than
the first-generation drugs.
30.3 Which of the following medications has the most
potential to significantly impair the ability to drive an
automobile?
A. Diphenhydramine.
B. Levocetirizine.
C. Fexofenadine.
D. Ranitidine.
Correct answer = A. Diphenhydramine can impair opera-
tion of an automobile by causing drowsiness and by impair-
ing accommodation. The other agents do not have this
restriction.
30.4 Which of the following histamine receptor antagonists
is known to enter the central nervous system readily
and is known to be sedative?
A. Hydroxyzine.
B. Cetirizine.
C. Desloratadine.
D. Loratadine.
E. Fexofenadine.
Correct answer = A. Choices B, C, D, and E are all second-
generation antihistamines that cross the blood–brain barrier
to a much lesser extent than hydroxyzine. Hydroxyzine is
the only drug that crosses the blood–brain barrier easily.Therapeutically, fexofenadine is a selective peripheral H₁ blocker
30.5 Which of the following statements about histamine
receptor antagonists is MOST ACCURATE?
A. Most antihistamines have no antimuscarinic effects.
B. α-Adrenergic effects of antihistamines may cause
hypertension.
C. First-generation antihistamines have no sedative
side effects.
D. Because of their cholinergic properties,
antihistamines may not be effective in the relief of
vertigo associated with motion sickness.
E. Headache may be associated with some second-
generation antihistamines.
Correct answer = E. Most first-generation antihistamines
have α receptor–mediated hypotensive effects, sedative
effects, and antimuscarinic (anticholinergic) effects. Second-
generation antihistamines have the effects listed in option E.
30.6 A passenger sitting next to you in a plane boasts that
he was a famous biochemist. He said he carboxylated
a sedating antihistamine, and it is now only partially
sedating and is a very well-known drug in the market.
Which drug is he talking about?
A. Hydroxyzine.
B. Cetirizine.
C. Diphenhydramine.
D. Doxylamine.
E. Cyproheptadine.
Correct answer =B. Choices A, C, D, and E are first-generation
antihistamines and are known to cross the blood–brain
barrier. Cetirizine is the carboxylated hydroxyzine.
30.7 Which of the following is an H1
-receptor antagonist
that also has serotonin receptor antagonism on the
appetite center with the ability to stimulate appetite?
A. Hydroxyzine.
B. Loratadine.
C. Diphenhydramine.
D. Cetirizine.
E. Cyproheptadine.
Correct answer = E. Cyproheptadine has significant sero-
tonin antagonism and is known to increase appetite.Cyproheptadine is a very potent antihistamine or inverse agonist of the H1 receptor.
30.8 Your neighbor said she used an H1
antihistamine that
was available over-the-counter (OTC), and it caused
her marked drowsiness and dry mouth and she slept
quite longer than usual. Which is the most possible
drug that she used?
A. Loratadine.
B. Levocetirizine.
C. Diphenhydramine.
D. Fexofenadine.
E. Desloratadine.
Correct answer = C. The only first-generation drug in the
list is diphenhydramine. Diphenhydramine and doxylamine,
another first-generation antihistamine, are common ingredi-
ents in OTC sleep products.
30.9 A patient is going on a deep sea fishing trip and is
worried about motion sickness. Which of the following
would be the most appropriate?
A. Dimenhydrinate 1 hour prior to departure.
B. Desloratadine 1 hour prior to departure.
C. Doxylamine 1 hour prior to departure.
D. Meclizine at onset of symptoms.
Correct answer = A. Dimenhydrinate and meclizine are
both useful for preventing the symptoms of motion sick-
ness. However, they are much more effective in preventing
symptoms than treating symptoms once they have started.
Therefore, they should be taken prior to expected travel/
boating, etc. Desloratadine and doxylamine are not useful
for motion sickness
30.10 A patient has a severe ear infection that is associated
with significant vertigo. Which of the following might
be helpful?
A. Azelastine.
B. Brompheniramine.
C. Meclizine.
D. Olopatadine.
Correct answer = C. Meclizine is useful for the treatment
of vertigo associated with vestibular disorders. Azelastine
and olopatadine are ophthalmic or intranasal antihista-
mines, but they are not useful for symptoms of ear infection.
Brompheniramine is a first-generation antihistamine that is
mainly used for allergy symptoms.
