Does one need to have a normal result in G6PD screening before he can take Malarial pills?
In some cases, yes. When a patient has been diagnosed with Plasmodium ovale or Plasmodium vivax infection, in addition to medication such as chloroquine to target the blood stages of the parasite, an additional drug, called primaquine, may also be required. Primaquine kills the liver stages, known as hypnozoites, of these forms of malaria, preventing relapse of infection later on.
However, primaquine is known to cause severe haemolytic anaemia in people who are G6PD deficient. G6PD deficiency is restricted to certain populations or segments of populations; therefore it may be that not every person requiring primaquine will be tested for their G6PD status, only those considered high risk for potential deficiency. Patients with severe G6PD deficiency should not take primaquine; unfortunately at this stage there are no alternative drug regimens available. Patients with mild forms of G6PD deficiency should take primaquine at an alternative dose to G6PD-normal patients, usually 0.75mg/kg bodyweight once a week for 8 weeks (as opposed to 0.25mg/kg bodyweight once a day for 5 or 14 days, depending on the case history of the patient and the physician’s recommendation).
There is also some evidence that quinine can cause haemolysis in patients with G6PD deficiency; such patients may also have increased blood concentrations of mefloquine when taken concurrently with primaquine. As such, combinations of quinine or mefloquine with primaquine in G6PD-deficient patients is not recommended.