Radical cure of plasmodium vivax is by:

Primaquine In contrast to other antimalarial drugs, primaquine is a poor erythrocytic schizontocide: has weak action on P. vivax, but blood forms of P. Jalciparum are totally insensitive. On the other hand, it is more active against the preerythrocytic stage of P. Jalciparum than that of P. vivax. Primaquine differs from all other available antimalarials in having a marked effect on primary as well as secondary tissue phases of the malarial parasite. It is highly active against gametocytes and hypnozoites. The mechanism of action of primaquine is not known. However, it is different from that of chloroquine. Though, resistance among P. vivax against primaquine can be induced, it is not a clinical problem. Essentials of medical pharmacology K D Tripathi Sixth edition Pg no 791