, Question 1
A patient with severe chloroquine-resistant Plasmodium falciparum malaria is
prescribed intravenous artesunate. Which statement best explains why
artesunate is preferred over quinine in this setting?
A. Artesunate is a slow-acting schizonticide that prevents recrudescence
by eliminating hypnozoites.
B. Artesunate rapidly reduces parasite biomass via iron-mediated
alkylation, lowering mortality compared to quinine.
C. Artesunate is a folate antagonist that synergizes with
sulfadoxine-pyrimethamine to overcome resistance.
D. Artesunate inhibits heme polymerization, causing accumulation of
toxic heme in the parasite digestive vacuole.
Correct Answer: B - Artesunate rapidly reduces parasite biomass
via iron-mediated alkylation, lowering mortality compared to
quinine.
RATIONALE
Artesunate is a fast-acting artemisinin that is activated by iron/heme to
generate free radicals that alkylate parasite proteins, leading to rapid
parasite clearance and reduced mortality in severe malaria. Option A is
wrong because artesunate does not eliminate hypnozoites (that is
primaquine). Option C describes antifolate synergy, not artesunate's
mechanism. Option D describes chloroquine's mechanism.
Question 2
A patient with giardiasis is prescribed metronidazole. Which instruction is
most important to include in patient education to prevent a disulfiram-like
reaction?
A. Avoid dairy products for 48 hours after completing therapy.
B. Abstain from alcohol during therapy and for at least 3 days after the
last dose.
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, C. Take the medication with grapefruit juice to enhance absorption.
D. Increase sun exposure to promote activation of the drug.
Correct Answer: B - Abstain from alcohol during therapy and for
at least 3 days after the last dose.
RATIONALE
Metronidazole can precipitate a disulfiram-like reaction (flushing,
tachycardia, vomiting) when combined with alcohol; patients must
avoid alcohol during and for at least 3 days after therapy. Dairy and
grapefruit juice do not cause this reaction. Sun exposure is unrelated.
Question 3
A patient with neurocysticercosis is prescribed albendazole. Which
pharmacokinetic property best explains the need for co-administration with a
fatty meal?
A. Albendazole is a prodrug that requires gastric acid for activation.
B. Albendazole has high first-pass metabolism that is saturable with food.
C. Albendazole's absorption is increased up to 5-fold with a fatty meal,
enhancing systemic availability.
D. Albendazole is a weak base that precipitates in alkaline environments.
Correct Answer: C - Albendazole's absorption is increased up to
5-fold with a fatty meal, enhancing systemic availability.
RATIONALE
Albendazole is poorly water-soluble; a fatty meal increases its oral
bioavailability significantly (up to 5-fold), which is critical for treating
systemic infections like neurocysticercosis. It is not a prodrug
requiring acid, and its first-pass metabolism is not saturable by food. It
does not precipitate in alkaline environments.
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A patient with severe chloroquine-resistant Plasmodium falciparum malaria is
prescribed intravenous artesunate. Which statement best explains why
artesunate is preferred over quinine in this setting?
A. Artesunate is a slow-acting schizonticide that prevents recrudescence
by eliminating hypnozoites.
B. Artesunate rapidly reduces parasite biomass via iron-mediated
alkylation, lowering mortality compared to quinine.
C. Artesunate is a folate antagonist that synergizes with
sulfadoxine-pyrimethamine to overcome resistance.
D. Artesunate inhibits heme polymerization, causing accumulation of
toxic heme in the parasite digestive vacuole.
Correct Answer: B - Artesunate rapidly reduces parasite biomass
via iron-mediated alkylation, lowering mortality compared to
quinine.
RATIONALE
Artesunate is a fast-acting artemisinin that is activated by iron/heme to
generate free radicals that alkylate parasite proteins, leading to rapid
parasite clearance and reduced mortality in severe malaria. Option A is
wrong because artesunate does not eliminate hypnozoites (that is
primaquine). Option C describes antifolate synergy, not artesunate's
mechanism. Option D describes chloroquine's mechanism.
Question 2
A patient with giardiasis is prescribed metronidazole. Which instruction is
most important to include in patient education to prevent a disulfiram-like
reaction?
A. Avoid dairy products for 48 hours after completing therapy.
B. Abstain from alcohol during therapy and for at least 3 days after the
last dose.
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, C. Take the medication with grapefruit juice to enhance absorption.
D. Increase sun exposure to promote activation of the drug.
Correct Answer: B - Abstain from alcohol during therapy and for
at least 3 days after the last dose.
RATIONALE
Metronidazole can precipitate a disulfiram-like reaction (flushing,
tachycardia, vomiting) when combined with alcohol; patients must
avoid alcohol during and for at least 3 days after therapy. Dairy and
grapefruit juice do not cause this reaction. Sun exposure is unrelated.
Question 3
A patient with neurocysticercosis is prescribed albendazole. Which
pharmacokinetic property best explains the need for co-administration with a
fatty meal?
A. Albendazole is a prodrug that requires gastric acid for activation.
B. Albendazole has high first-pass metabolism that is saturable with food.
C. Albendazole's absorption is increased up to 5-fold with a fatty meal,
enhancing systemic availability.
D. Albendazole is a weak base that precipitates in alkaline environments.
Correct Answer: C - Albendazole's absorption is increased up to
5-fold with a fatty meal, enhancing systemic availability.
RATIONALE
Albendazole is poorly water-soluble; a fatty meal increases its oral
bioavailability significantly (up to 5-fold), which is critical for treating
systemic infections like neurocysticercosis. It is not a prodrug
requiring acid, and its first-pass metabolism is not saturable by food. It
does not precipitate in alkaline environments.
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