In areas with known chloroquine resistance, which malaria regimen is preferred?

• A. Quinine sulfate plus doxycycline
• B. Chloroquine plus primaquine
• C. Artemisinin monotherapy
• D. Mefloquine alone

Answer: (A)

When chloroquine resistance is known, you need a regimen that uses a different mechanism to rapidly clear the blood-stage parasites and reduce the chance of treatment failure. Quinine sulfate provides strong activity against chloroquine-resistant Plasmodium falciparum, and pairing it with doxycycline adds a second mechanism that enhances parasite kill and helps prevent recrudescence. This combination has a long history of effectiveness in resistant malaria and remains a reliable choice when newer regimens aren’t available or appropriate.

Chloroquine plus primaquine wouldn’t work well here because chloroquine can’t reliably clear the resistant blood stages, and primaquine targets liver hypnozoites in vivax and ovale rather than the blood forms of falciparum. Artemisinin monotherapy is discouraged because resistance can develop, and modern guidelines favor artemisinin-based combination therapies rather than a single-agent artemisinin. Mefloquine alone can be effective in some settings, but monotherapy carries risks of resistance and adverse effects, making the quinine-doxycycline pairing the more robust option in known chloroquine-resistant areas.