A 24-year-old man presents with cyclical fever, chills, and rigors after returning from deployment in an endemic area. Peripheral blood smear shows Plasmodium vivax ring forms with Schüffner dots. He is treated with chloroquine with symptomatic improvement. Which additional treatment is required to prevent relapse?

• A Primaquine ✓
• B Mefloquine
• C Artemether-lumefantrine
• D Doxycycline

Explanation

P. vivax forms dormant hypnozoites in the liver that cause relapses weeks to months after the primary infection. Primaquine is the only drug that eliminates hypnozoites and provides radical cure. Chloroquine treats only the blood-stage infection. Before starting primaquine, G6PD testing is mandatory because primaquine causes severe hemolytic anemia in G6PD-deficient individuals.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.