Primaquine for all: is it time to simplify malaria treatment in co-endemic areas?

Different strains of vivax have distinct relapse patterns,6 and pharmacogenetics also seems to have a role in primaquine metabolism, which could affect relapse as primaquine only becomes active once metabolised (CYP 2D6 pathway) into its active metabolites.7 However, acute infections may also trigger relapses.8 Data showing possible P vivax relapses after P falciparum infection were obtained first in Thailand,9 but an analysis reported in The Lancet Infectious Diseases by Robert Commons and colleagues10 provides statistical robustness regarding this observation. [...]the number of cases of P falciparum needed to treat with radical cure to prevent one P vivax recurrence by day 63—ranging between 4·7 and 5·0 as proposed by the study investigators—would seem to amply justify this radical change in malaria treatment. [...]in areas where glucose-6-phosphate dehydrogenase (G6PD) deficiency is prevalent, such as southeast Asia, primaquine use would need to be expanded carefully on account of the potential hazards that such a prohaemolytic drug might have in individuals lacking full functionality of the G6PD enzyme.12 The availability of point-of-care tests to detect G6PD deficiency (ie, G6PD activity lower than 30%) might help the safe use of primaquine against both malaria species.13 In the real world, however, the switch from a simple 3-day P falciparum treatment regimen with an artemisinin-based combination therapy (ACT) to a 14-day course including primaquine might be met with some reluctance among health providers and even the general population.