Possible Interaction: Quinine and Artesunate

“In some areas clinicians have combined parenteral artesunate and quinine in the belief that the 2 drugs would be additive or synergistic in severe malaria.”

“Mortality was 15% in the artesunate group and 22% in the quinine group, a reduction of 34.7% (95% confidence interval: 18.5–47.6%) in the artesunate group , with almost all the benefit reported in those with high parasite counts.”

“The geometric mean 50% inhibitory concentration (IC50) values from primary infections were: dihydroartemisinin 1.2 ng/mL, artesunate 1.6 ng/mL, artemether …/mL, mefloquine 27 ng/mL and halofantrine 4.1 ng/mL. A significant positive correlation was found between the susceptibility in vitro to artesunate … quinine (r = …).”

“ Artesunate and artemether were more potent than quinine in inhibiting both adherence properties.”

“Empirical addition of parenteral quinine to artesunate for treatment is recommended as a precautionary measure.”

“Treatment with quinine has been described as a risk factor; however the syndrome may also occur following treatment with intravenous artesunate.”

“ConclusionsThe great majority of P. falciparum isolates in the Brazilian malaria-endemic area remain resistant to chloroquine, and the decreased sensitivity to quinine , mefloquine and artesunate observed in 10–20% of the isolates must be taken with concern, especially for artesunate.”

“To delay the emergence of resistance, ‘… drugs (mefloquine and halofantrine and perhaps quinine ) may not be the best candidates since … evidence of cross resistance between them and artesunate in vitro’ (L.K. Basco and J. Le Bras, In vitro … artemisinin derivatives against African isolates and clones of Plasmodium falciparum.”