Skip to Main Content

Chapter 52: Antiprotozoal Drugs

Which statement about antiprotozoal drugs is accurate?

(A) Chloroquine is an inhibitor of plasmodial dihydrofolate reductase

(B) Mefloquine destroys secondary exoerythrocytic schizonts

(C) Primaquine is a blood schizonticide and does not affect secondary tissue schizonts

(D) Proguanil complexes with double-stranded DNA-blocking replication

(E) Trimethoprim-sulfamethoxazole is the drug of choice for Pneumocystis jiroveci pneumonia

Proguanil (not chloroquine) is an inhibitor of dihydrofolate reductase. Primaquine (not mefloquine) is the drug that destroys secondary exoerythrocytic schizonts. TMP-SMZ is the drug of choice for Pneumocystis jiroveci pneumonia. The answer is E.

Plasmodial resistance to chloroquine is due to

(A) Change in receptor structure

(B) Decreased accumulation of the drug in the food vacuole

(C) Increased activity of DNA repair mechanisms

(D) Increased synthesis of dihydrofolate reductase

(E) Induction of drug-inactivating enzymes

Resistance to chloroquine in P falciparum can result from decreased accumulation of the drug in the food vacuole caused by the activity of a transporter system encoded by the pfcrt gene. The answer is B.

A traveler in a geographical region where chloroquine-resistant P falciparum is endemic used a drug for prophylaxis but nevertheless developed a severe attack of P vivax malaria.

The drug used for prophylaxis was probably

(A) Atovaquone

(B) Iodoquinol

(C) Mefloquine

(D) Proguanil

(E) Tetracycline

Mefloquine is a recommended drug for prophylaxis in regions of the world where chloroquine-resistant P falciparum is endemic. One dose of mefloquine weekly starting before travel and continuing until 4 wk after leaving the region is the preferred regimen. Doxycycline (not tetracycline) is an alternative drug for this indication, as is atovaquone plus proguanil (Malarone). The answer is C.

A traveler in a geographical region where chloroquine-resistant P falciparum is endemic used a drug for prophylaxis but nevertheless developed a severe attack of P vivax malaria.

Which drug should be used for oral treatment of the acute attack of P vivax malaria but does not eradicate exoerythrocytic forms of the parasite?

(A) Chloroquine

...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.