Artesunate-mefloquine (AS-MQ) is a common and widely available ACT, and along with artemether-lumefantrine (A-L) is one of only 2 first line WHO recommended options for the treatment of uncomplicated P. falciparum infection which are registered in Malaysia and produced according to international good manufacturing practice (GMP) standards. ACTs are the current mainstay of malaria elimination efforts [33], with a mechanism of action resulting both in a rapid reduction in parasite mass and resolution of clinical features, while the long acting component eliminates residual parasites and delays the development of de novo resistance [34, 35]. Safety and tolerability of all ACTs are dependent on their partner drug [36], and while gastro-intestinal and self-limiting neuro-psychiatric adverse events have been reported with mefloquine, multiple safety and efficacy trials have recommended its use in both adults and children for uncomplicated falciparum malaria [37-40]. Due to concerns over the safety of mefloquine in the first trimester of pregnancy [41], and its use in patients with pre-existing psychiatric disorders or those who have previously had cerebral malaria, it is currently not advised for these groups [36].