Comparison of Two Antimalarial Drugs Regimens in Patient With Plasmodium Vivax Malaria in Thailand
Status:
Unknown status
Trial end date:
2014-12-01
Target enrollment:
Participant gender:
Summary
In Thailand, the proportion of P.vivax infection has now been increasing and is equal to
Plasmodium falciparum since 1998. The incidence of P.vivax has recently been reported as 20
per 1000 population per year. Unlike Plasmodium falciparum, P.vivax infection rarely develops
into complicated malaria and death is unusual. However, P.vivax has a dormant stage (the
hypnozoite) that persists in the human liver and may cause relapse weeks, months, or even
years later. Therefore, P.vivax infection is considered to have greater impact on morbidity
than mortality, resulting in significant social and economic burden. Moreover, it is very
difficult to control P.vivax transmission, because gametocytes appear almost simultaneously
with schizonts.
Radical treatment of the infection, therefore, normally consists of a blood schizontocidal
course of chloroquine and a course primaquine for the elimination of the hypnozoites as
anti-relapse therapy. In Thailand, chloroquine and primaquine have remained the mainstay
chemotherapeutics for the treatment of P.vivax for more than 60 years and resistance has not
yet been reported . The relapse rates at day 28 are about 50% without primaquine therapy and
about 20% with standard primaquine therapy. Relapse has not been observed among patients
receiving high dose primaquine therapy (30 mg daily for 14 days).
Since January 2007, the evidence of reduced susceptibility of Plasmodium falciparum to
artemisinins in Western Cambodia at Thai-Cambodia border was first presented and confirmed in
a subsequent detailed pharmacokinetic-pharmacodynamic study. Nevertheless, a trend of gradual
decline of in vitro sensitivity to chloroquine has been documented in some areas of the
country, particularly Thai-Myanmar border. There has been no clinical-parasitological
evidence of chloroquine resistant P.vivax in Thai-Cambodia border, Thailand.
The objectives of the present study are to assess in vivo efficacy of first line regimen of
chloroquine given with primaquine, and in vitro susceptibility of P.vivax isolates in areas
along Thai-Cambodia border, Thailand.