Chloroquine and primaquine: combining old drugs as a new weapon against falciparum malaria?

A recent publication has shown that primaquine, a drug used to clear liver-stage Plasmodium vivax infection, acts as a chloroquine-resistance reversing agent for Plasmodium falciparum in culture. Primaquine is active as a chloroquine-resistance reverser at concentrations that could be clinically relevant. As primaquine and chloroquine are already used together in the treatment of P. vivax, this is potentially a cheap way of reviving and extending the life of chloroquine.