Ant malarial drug resistance exists when adequate drug blood concentration are to kill a previously susceptible parasite. This occurs by evolutionary selection of spontaneously arising mutant parasites that aredrug insensitive. Drug resistance is often, but not always, due to point mutations that change drug accumulation/effiux in the erythrocyte or reduce affinity for target molecule. Drug resistance can present in several ways to include: failure of treatment to clear parasites in a single patient, increase in malaria prevalence, malaria occurring in areas where it had not been seen recently such as epidemic malaria.