8
a. Injecting penicillin intradermally
b. Taking a thorough medical history
c. Placing a drop of penicillin on the eye
d. Having the patient inhale a penicillin aerosol
e. Injecting a small amount of penicillin intravenously
(b) all of the other methods involve unacceptable risk. Once
sensitized, even a small amount can cause an allergic
response. Remember, it is not a dose-related response that
won’t be problematic if you only inject a little bit.
14. Which of the following antibiotics is the substitute of choice for
penicillin in the penicillin-sensitive patient?
a. Bacitracin
b. Erythromycin
c. Tetracycline
d. Chloramphenicol
(b) boy, if you haven’t heard this a zillion times by now.. None of
the alternatives listed would be a problem in terms of cross-
allergenicity, but the reason (b) is the right answer is that the
spectrum of activity of erthromycin is very similar to penicillin. The
others offer a much broader spectrum of coverage than we usually
require; always use the drug with the narrowest spectrum possible
that includes the microbe in question.
Standards have now
changed such that clindamycin is the drug of choice in this
situation. But if they don’t include clindamycin, look for
erythromycin, or for that matter Azithromycin
15. Most anaphylactic reactions to penicillin occur
a. When the drug is administered orally
b. In patients who have already experienced an allergic reaction to
the drug
c. In patients with a negative skin test to penicillin allergy
d. When the drug is administered parenterally
e. Within minutes after drug administration
i.
(a), (b) and (d)
ii.
(b), (c) and (d)
iii. (b), (d) and (e)
iv. (b) and (e) only
v. (c), (d) and (e)
(iii) memorize
16. Which of the following penicillins has a broader gram-negative
spectrum than penicillin G?
a. Nafcillin
b. Ampicillin
c. Cephalexin
d. Methicillin
e. Penicillin V
(b) that’s why it is considered an “extended-spectrum” form of
penicillin
17. Which of the following penicillins has the best gram-negative
spectrum?
a. Nafcillin
b. Ampicillin
c. Methicillin
d. Penicillin V
e. Phenethicillin
(b) didn’t they just ask the same thing in the question above?
18. Which of the following antibiotics should be considered the drug of
choice in the treatment of infection caused by a penicillinase-
producing staphylococcus?
a. Neomycin
b. Ampicillin
c. Tetracycline
d. Penicillin V
e. Dicloxacillin
(e) that’s really the only use for dicloxacillin
19. Oral infections caused by organisms that produce penicillinase
should be treated with
a.
Ampicillin
b.
Dicloxacillin
c.
Erythromycin
d.
Any of the above
e.
Only (a) or (c) above
(b) of those listed only (b) is penicillinase resistant. Ampicillin is an
extended spectrum penicillin, and is not penicillinase resistant.
Erythromycin shouldn’t be affected by penicillinases, since it isn’t a
peniciilin, but it doesn’t work against staph for other reasons.
20. Which of the following antibiotics is LEAST effective against
penicillinase-producing microorganisms?
a. Ampicillin
b. Cephalexin
c. Methicillin
d. Clindamycin
e. Erythromycin
(a) same question asked backassward
21. Which of the following is a bactericidal antibiotic used specifically in
the treatment of infections caused by
Pseudomonas
species and
indole-positive
Proteus
species?
a. Ampicillin
b. Penicillin V
c. Tetracycline
d. Dicloxacillin
e. Carbenicillin
(e) Wow, I bet you didn’t think they would ask something like
this!. An extended spectrum agent is required. Ampicillin is
ineffective, while Pen-V is too narrow in spectrum.
22. Penicillin's effectiveness against rapidly growing cells is primarily due
to its effect on
a. Protein synthesis
b. Cell wall synthesis
c. Nucleic acid synthesis
d. Chelation of metal ions
e. Cell membrane permeability
(b) memorize, memorize
23. Chlortetracycline acts by interfering with
a. Cell wall synthesis
b. Nuclear acid synthesis
c. Protein synthesis on bacterial but not mammalian ribosomes
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