Volume 11, Number 2—February 2005
Malaria Epidemic and Drug Resistance, Djibouti
|Drugs||Isolates studied (n)||Mean IC50*||95% confidence interval||Cut-off value||% resistant isolates|
|Chloroquine||27||326 nmol/L||224–474 nmol/L||>100 nmol/L||93|
|Amodiaquine||27||10.0 nmol/L||8.0–12.6 nmol/L||>80 nmol/L||0|
|Cycloguanil||24||13 nmol/L||8–21 nmol/L||>500 nmol/L||4|
|Pyrimethamine||25||69 nmol/L||41–117 nmol/L||>2,000 nmol/L||4|
*The 50% inhibitory concentration (IC50) of chloroquine diphosphate, amodiaquine, pyrimethamine dihydrochloride, and cycloguanil, i.e., the drug concentration corresponding to 50% of the uptake of 3H-hypoxanthine by the parasites in drug-free control wells, was determined by nonlinear regression analysis of log-dose/response curves. Mean IC50 and proportion of resistant isolates according to cut-off values are indicated. Data were expressed as the geometric mean IC50 and 95% confidence intervals were calculated.