Primaquine vs Chloroquine, mefloquine, and atovaquone-proguanil
How to tell Primaquine and Chloroquine, mefloquine, and atovaquone-proguanil apart when a board question makes them look alike.
Primaquine clears dormant liver forms; the others mainly cover blood-stage treatment or prophylaxis lanes.
Side by side
Liver hypnozoite eradication for relapsing malaria species, with mandatory G6PD concern because of hemolysis risk.
Blood-stage/prophylaxis drugs: chloroquine affects heme detoxification, mefloquine has neuropsychiatric limits, and atovaquone-proguanil combines mitochondrial plus folate logic.
Primaquine targets hepatic forms and can generate oxidative stress in red cells.
Chloroquine interferes with heme polymerization; mefloquine is quinoline-like blood-stage therapy; atovaquone-proguanil combines electron transport and folate-pathway effects.
Relapse prevention for P vivax/P ovale or G6PD testing points primaquine.
Retinopathy/heme detoxification points chloroquine; psychiatric warning points mefloquine; better-tolerated prophylaxis combination points atovaquone-proguanil.
The trap
A negative blood smear after malaria treatment does NOT prove cure. Dormant liver hypnozoites of P. vivax and P. ovale can persist for months or years after the bloodstream is cleared and cause relapsing illness. Primaquine (or single-dose tafenoquine) is the ONLY drug class that eradicates hypnozoites; chloroquine and other blood-stage agents do not penetrate the liver dormant forms. Always screen for G6PD deficiency before primaquine or tafenoquine because both cause severe hemolysis in G6PD-deficient patients.
The repair move
For any malaria question, walk three steps: (1) identify species (P. falciparum is the most lethal, no hypnozoites; P. vivax and P. ovale form hypnozoites; P. malariae is chronic low-grade; P. knowlesi resembles falciparum); (2) assign drug by phase (blood-stage prophylaxis or treatment uses chloroquine in sensitive areas, mefloquine but avoid with psychiatric history, atovaquone-proguanil for daily dosing, or doxycycline; hypnozoite eradication for P. vivax / P. ovale requires primaquine or tafenoquine screen G6PD first); (3) severe P. falciparum needs IV artesunate as first-line.
Try a free question
CoreA patient with relapsing malaria due to a species with dormant liver hypnozoites is prescribed primaquine after quantitative G6PD testing. Which role best fits primaquine?
Show answer and explanation
Answer: A. Eradicates liver hypnozoites. Primaquine targets hepatic hypnozoites of relapsing malaria species and can cause hemolysis in G6PD deficiency.
Why the other choices are tempting
- B. Chloroquine is a blood-stage drug for susceptible parasites and does not eradicate hypnozoites.
- C. Proguanil contributes folate-pathway activity in atovaquone-proguanil combinations.
- D. Mefloquine is remembered for neuropsychiatric adverse effects.
- E. Neuraminidase inhibition is oseltamivir for influenza.
Flashcards
Tap a card to flip it.
What is the fastest separator for Primaquine vs Chloroquine, mefloquine, and atovaquone-proguanil?
Primaquine clears dormant liver forms; the others mainly cover blood-stage treatment or prophylaxis lanes.
What clue should make you choose Primaquine?
Liver hypnozoite eradication for relapsing malaria species, with mandatory G6PD concern because of hemolysis risk.
Quick answers
What is the fastest way to tell Primaquine from Chloroquine, mefloquine, and atovaquone-proguanil?
Primaquine clears dormant liver forms; the others mainly cover blood-stage treatment or prophylaxis lanes.
What is the key clue for Primaquine?
Liver hypnozoite eradication for relapsing malaria species, with mandatory G6PD concern because of hemolysis risk.
What is the key clue for Chloroquine, mefloquine, and atovaquone-proguanil?
Blood-stage/prophylaxis drugs: chloroquine affects heme detoxification, mefloquine has neuropsychiatric limits, and atovaquone-proguanil combines mitochondrial plus folate logic.
What is the common trap with Primaquine vs Chloroquine, mefloquine, and atovaquone-proguanil?
A negative blood smear after malaria treatment does NOT prove cure. Dormant liver hypnozoites of P. vivax and P. ovale can persist for months or years after the bloodstream is cleared and cause relapsing illness. Primaquine (or single-dose tafenoquine) is the ONLY drug class that eradicates hypnozoites; chloroquine and other blood-stage agents do not penetrate the liver dormant forms. Always screen for G6PD deficiency before primaquine or tafenoquine because both cause severe hemolysis in G6PD-deficient patients.