NU 578 Unit 3 Exam (PDF) | Updated Exam
Questions | University of South Alabama
Question 1
A patient with an anaphylactic penicillin allergy requires
treatment for streptococcal pharyngitis. Which antibiotic
is contraindicated?
A) Azithromycin
B) Cephalexin
C) Clindamycin
D) Penicillin VK
Correct answer: D
Rationale: Penicillin VK is absolutely contraindicated in
anaphylactic penicillin allergy. Azithromycin, cephalexin
(with caution), and clindamycin are alternatives, but
cephalexin carries a low cross-reactivity risk.
Question 2
Which penicillin has the best activity
1
,against Pseudomonas aeruginosa?
A) Penicillin G
B) Ampicillin
C) Nafcillin
D) Piperacillin-tazobactam
Correct answer: D
Rationale: Piperacillin-tazobactam is an antipseudomonal
penicillin. Penicillin G, ampicillin, and nafcillin have no
significant pseudomonal activity.
Question 3
A patient develops diarrhea and abdominal cramping 5
days after starting amoxicillin-clavulanate. What is the
most likely cause?
A) Clostridioides difficile infection
B) Amoxicillin rash
C) Beta-lactamase inhibitor toxicity
D) Direct GI irritation
2
,Correct answer: D
Rationale: Amoxicillin-clavulanate commonly causes direct
GI irritation and diarrhea (up to 20%), often starting
early. C. difficile typically occurs after 7–10 days of
antibiotics.
Question 4
A pregnant patient at 30 weeks gestation has syphilis.
Which penicillin is first-line?
A) Amoxicillin
B) Penicillin G benzathine
C) Doxycycline
D) Ceftriaxone
Correct answer: B
Rationale: Penicillin G benzathine (IM) is first-line for
syphilis in pregnancy. Doxycycline is contraindicated.
Ceftriaxone is less effective and not first-line.
3
, Question 5
Which drug is a penicillinase-resistant penicillin used for
methicillin-susceptible S. aureus (MSSA)?
A) Ampicillin
B) Piperacillin
C) Nafcillin
D) Amoxicillin
Correct answer: C
Rationale: Nafcillin and oxacillin are penicillinase-
resistant penicillins used for MSSA. Ampicillin and
amoxicillin are susceptible to staphylococcal penicillinase.
Question 6
A patient on intravenous ampicillin develops a diffuse
maculopapular rash, no fever or eosinophilia. What is the
most appropriate action?
A) Stop ampicillin immediately and start vancomycin
B) Give diphenhydramine and continue ampicillin if rash
4
Questions | University of South Alabama
Question 1
A patient with an anaphylactic penicillin allergy requires
treatment for streptococcal pharyngitis. Which antibiotic
is contraindicated?
A) Azithromycin
B) Cephalexin
C) Clindamycin
D) Penicillin VK
Correct answer: D
Rationale: Penicillin VK is absolutely contraindicated in
anaphylactic penicillin allergy. Azithromycin, cephalexin
(with caution), and clindamycin are alternatives, but
cephalexin carries a low cross-reactivity risk.
Question 2
Which penicillin has the best activity
1
,against Pseudomonas aeruginosa?
A) Penicillin G
B) Ampicillin
C) Nafcillin
D) Piperacillin-tazobactam
Correct answer: D
Rationale: Piperacillin-tazobactam is an antipseudomonal
penicillin. Penicillin G, ampicillin, and nafcillin have no
significant pseudomonal activity.
Question 3
A patient develops diarrhea and abdominal cramping 5
days after starting amoxicillin-clavulanate. What is the
most likely cause?
A) Clostridioides difficile infection
B) Amoxicillin rash
C) Beta-lactamase inhibitor toxicity
D) Direct GI irritation
2
,Correct answer: D
Rationale: Amoxicillin-clavulanate commonly causes direct
GI irritation and diarrhea (up to 20%), often starting
early. C. difficile typically occurs after 7–10 days of
antibiotics.
Question 4
A pregnant patient at 30 weeks gestation has syphilis.
Which penicillin is first-line?
A) Amoxicillin
B) Penicillin G benzathine
C) Doxycycline
D) Ceftriaxone
Correct answer: B
Rationale: Penicillin G benzathine (IM) is first-line for
syphilis in pregnancy. Doxycycline is contraindicated.
Ceftriaxone is less effective and not first-line.
3
, Question 5
Which drug is a penicillinase-resistant penicillin used for
methicillin-susceptible S. aureus (MSSA)?
A) Ampicillin
B) Piperacillin
C) Nafcillin
D) Amoxicillin
Correct answer: C
Rationale: Nafcillin and oxacillin are penicillinase-
resistant penicillins used for MSSA. Ampicillin and
amoxicillin are susceptible to staphylococcal penicillinase.
Question 6
A patient on intravenous ampicillin develops a diffuse
maculopapular rash, no fever or eosinophilia. What is the
most appropriate action?
A) Stop ampicillin immediately and start vancomycin
B) Give diphenhydramine and continue ampicillin if rash
4
