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cerrar este libroGuidelines for the Treatment of Malaria (WHO; 2006; 266 pages) Ver el documento en el formato PDF
Ver el documentoGlossary
Ver el documentoAbbreviations
abrir esta carpeta y ver su contenido1. Introduction
Ver el documento2. The clinical disease
abrir esta carpeta y ver su contenido3. Treatment objectives
abrir esta carpeta y ver su contenido4. Diagnosis of malaria
abrir esta carpeta y ver su contenido5. Resistance to antimalarial medicines9
abrir esta carpeta y ver su contenido6. Antimalarial treatment policy
abrir esta carpeta y ver su contenido7. Treatment of uncomplicated P. Falciparum malaria10
abrir esta carpeta y ver su contenido8. Treatment of severe falciparum malaria14
cerrar esta carpeta9. Treatment of malaria caused by P. vivax, P. ovale or P. malariae19
Ver el documento9.1 Diagnosis
Ver el documento9.2 Susceptibility of P. vivax, P. ovale and P. malariae to antimalarials
Ver el documento9.3 Treatment of uncomplicated vivax malaria
Ver el documento9.4 Treatment of severe vivax malaria
Ver el documento9.5 Treatment of malaria caused by P. ovale and P. malariae
Ver el documento9.6 Monitoring therapeutic efficacy for vivax malaria
Ver el documento10. Mixed malaria infections
abrir esta carpeta y ver su contenido11. Complex emergencies and epidemics
abrir esta carpeta y ver su contenidoAnnexes
 

9.3 Treatment of uncomplicated vivax malaria

9.3.1 Blood stage infection

There have been fewer studies on the treatment of malaria caused by P. vivax than of falciparum malaria - only 11% of 435 published before 2004. For chloroquine-sensitive vivax malaria (i.e. in most places where P. vivax is prevalent) the conventional oral chloroquine dose of 25 mg base/kg bw is well tolerated and effective. Some have advocated lower total doses, but this is not recommended as it might encourage the emergence of resistance. Chloroquine is given in an initial dose of 10 mg base/kg bw followed by either 5 mg/kg bw at 6 h, 24 h and 48 h or, more commonly, by 10 mg/kg bw on the second day and 5 mg/kg bw on the third day. It is also clear that if ACT treatment is given, the response is as good as or better than in falciparum malaria. The exception to this is a regimen containing sulfadoxine-pyrimethamine. It appears that P. vivax has developed resistance to sulfadoxine-pyrimethamine more rapidly than has P. falciparum, so that artesunate + sulfadoxine-pyrimethamine may not be effective against P. vivax in many areas.

Chloroquine-resistant vivax malaria

There are relatively few data on treatment responses in chloroquine-resistant vivax malaria. Studies from Indonesia indicate that amodiaquine is efficacious, and there is some evidence that mefloquine and quinine can also be used. The artemisinin derivatives would also be expected to be highly effective, and artemether-lumefantrine could be an alternative treatment. However, there are insufficient clinical data to confirm this.

9.3.2 Liver stage infection

To achieve radical cure, relapses must be prevented by giving primaquine. The frequency and pattern of relapses varies geographically, however. It has become clear in recent years that whereas 50-60% of P. vivax infections in South-East Asia relapse, the frequency is lower in Indonesia (30%) and the Indian subcontinent (15-20%). Some P. vivax infections in the Korean peninsula (now the most northerly of human malarias) have an incubation period of nearly one year. Thus the preventive efficacy of primaquine must be set against the prevalent relapse frequency. It appears that the total dose of 8-aminoquinoline given is the main determinant of curative efficacy against liver-stage infection. There is no evidence that the short courses of primaquine widely recommended (such as 5-day regimens) have any efficacy. Primaquine should be given for 14 days. The usual adult oral dose is 15 mg base (0.25 mg/kg bw per day) but in South-East Asia, particularly Indonesia, and in Oceania, higher doses (0.5 mg base/kg bw per day) are required. Primaquine causes abdominal discomfort when taken on an empty stomach; it should always be taken with food.

There has been debate as to whether primaquine should be given in endemic areas. Repeated vivax malaria relapses are debilitating at any age, but if reinfection is very frequent, then the risks of widespread use of primaquine may exceed the benefits. In low-transmission areas, the benefits of deploying primaquine are considered to exceed the risks, but in areas of sustained high transmission (such as on the island of New Guinea), P. vivax infection is very frequent, immunity is acquired, and the risks of widespread deployment of primaquine are considered to outweigh the benefits.

Primaquine and glucose-6-phosphate dehydrogenase deficiency

The inherited sex-linked deficiency in glucose-6-phosphate dehydrogenase (G6PD) is associated with some protection against falciparum malaria, but increased susceptibility to oxidant haemolysis. The prevalence of G6PD deficiency varies but can be as high as 30%. There are many different genotypes, each with different levels of deficiency. Primaquine is an oxidant and causes variable haemolysis in G6PD-deficient individuals. Fortunately primaquine is eliminated rapidly and so haemolysis is self-limiting provided no further medicine is taken. Screening for G6PD deficiency is not generally available outside hospitals, although rapid tests are under development. Many patients are therefore unaware of their G6PD status. If a patient is known to be severely G6PD deficient then primaquine should not be given. For the majority of patients with mild variants of the deficiency, primaquine should be given in a dose of 0.75 mg base/kg bw once a week for 8 weeks. If significant haemolysis occurs on treatment then primaquine should be stopped.

Summary of recommendations on the treatment of uncomplicated vivax malaria

RECOMMENDATIONS

LEVEL OF EVIDENCE

Chloroquine 25 mg base/kg bw divided over 3 days, combined with primaquine 0.25 mg base/kg bw, taken with food once daily for 14 days is the treatment of choice for chloroquine-sensitive infections. In Oceania and South-East Asia the dose of primaquine should be 0.5 mg/kg bw.

O, E

Amodiaquine (30 mg base/kg bw divided over 3 days as 10 mg/kg bw single daily doses) combined with primaquine should be given for chloroquine-resistant vivax malaria.

O, E

In moderate G6PD deficiency, primaquine 0.75 mg base/kg bw should be given once a week for 8 weeks. In severe G6PD deficiency, primaquine should not be given.

O, E

Where ACT has been adopted as the first-line treatment for P. falciparum malaria, it may also be used for P. vivax malaria in combination with primaquine for radical cure. Artesunate + sulfadoxine-pyrimethamine is the exception as it will not be effective against P. vivax in many places.

O, E

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