Antimalarial drugs reduce cytoadherence and resetting of Plasmodium falciparum

The in vivo and in vitro effects of antimalarials on cytoadherence and rosette formation were studied in 17 patients with severe and 46 with uncomplicated falciparum malaria. Cytoadherence was increased in severe malaria (P < .001). Artesunate and artemether were more potent than quinine in inhibiting both adherence properties. Artesunate was the most rapidly acting drug tested, producing > 50% inhibition of both cytoadherence and resetting in vivo and in vitro within 2 h of drug exposure. Exposure to quinine for greater than or equal to 4 h in vivo reduced resetting by > 50%, but not cytoadherence. Quinine did not reduce cytoadherence or resetting significantly in vitro with exposure times of less than or equal to 8 h. These results suggest that artemisinin derivatives are more effective than quinine in preventing pathologic processes in parasitized erythrocytes that contribute to microvascular obstruction in severe malaria.