Drugs that cure malaria caused by P. falciparum infection do not
necessarily directly affect the gametocyte, which is the stage of the
parasite that infects mosquitoes to complete the transmission cycle.
Primaquine (PQ), a drug with antimalarial properties, does not cure P.
falciparum infection but does kill P. falciparum gametocytes. Because of
this property, this drug has long been recommended as a single dose or
short course add-on to P. falciparum infection treatment regimens. It is
now recommended by the World Health Organization (WHO) and several
national malaria control programs, with the intention of reducing
community level malaria transmission. However, this drug also has
potentially serious side effects in people with glucose-6-phosphate
dehydrogenase (G6PD) deficiency, a common genetic variant. When they
take this drug it may cause haemolysis (disintegration of red blood
cells) which can be serious. This review examines the evidence of
benefits and harms of PQ from trials where it has been used as an
additional treatment intended to prevent malaria transmission.
We found no studies testing whether the drug influences transmission
intensity of malaria, and just one small study suggesting it reduces the
infectiousness of the parasite present in infected people to the
mosquito. PQ probably reduces the potential infectiousness of the
parasite in people, as measured by the numbers of gametocytes
circulating in the blood for up to six weeks after treatment. Regarding
safety, one study reported that there was a greater reduction in
haemoglobin values in the PQ group at day 8, so the safety of the drug
remains uncertain if given to populations where G6PD occurs. Evidence of
benefit and of safety is insufficient to recommend routine use of PQ as
an add-on for people being treated for malaria.
Graves, P.M.; Gelband, H.; Garner, P. Primaquine for reducing Plasmodium falciparum transmission. Cochrane Database of Systematic Reviews (2012) : [DOI: 10.1002/14651858.CD008152.pub2]
Primaquine for reducing Plasmodium falciparum transmission.