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9. Treatment of malaria caused by P. vivax, P. ovale or P. malariae

In general, P. vivax is sensitive to all the other antimalarial drugs and slightly less sensitive
to mefloquine (although mefloquine is still effective). In contrast to P. falciparum, asexual
stages of P. vivax are susceptible to primaquine. Thus, chloroquine plus primaquine can
be considered as a combination treatment. The only drugs with significant activity against
the hypnozoites are the 8-aminoquinolines (buloquine, primaquine, tafenoquine).

There is no standardized in vitro method of drug assessment for hypnozoiticidal activity.
In vivo assessment suggests that tolerance of P. vivax to primaquine in eastern Asia and
Oceania is greater than elsewhere.

9.3 treatment of uncomplicated vivax malaria

9.3.1 Blood stage infection

For chloroquine-sensitive vivax malaria (i.e. in most places where P. vivax is prevalent),
oral chloroquine at a total dose of 25 mg base/kg body weight is effective and well tolerated.
Lower total doses are not recommended, as these might encourage the emergence of
resistance. Chloroquine is given in an initial dose of 10 mg base/kg body weight followed
by either 5 mg/kg body weight at 6 h, 24 h and 48 h or, more commonly, by 10 mg/kg
body weight on the second day and 5 mg/kg body weight on the third day. Recent studies
have also demonstrated the efficacy of the recommended ACTs in the treatment of vivax
malaria. The exception to this is artesunate plus sulfadoxine-pyrimethamine. Though
there has been one study from Afghanistan reporting good efficacy to AS+SP, it appears
that P. vivax has developed resistance to sulfadoxine-pyrimethamine more rapidly than
P. falciparum has; hence, artesunate plus sulfadoxine-pyrimethamine may not be effective
overall against P. vivax in many areas.

9.3.1.1 Chloroquine-resistant vivax malaria
There is evidence that amodiaquine, mefloquine and quinine are effective in the treatment
of chloroquine-resistant P. vivax malaria. ACTs based on either amodiaquine, mefloquine
or piperaquine, rather than monotherapy, are the recommended treatment of choice. Two
trials have compared DHA+PPQ to alternative ACTs (AL6 and AS+AQ) in Indonesia.
There are no trials comparing DHA+PPQ and AS+MQ in P. vivax mono-infection.

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