P.vivax Malaria Treatment

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QUESTION

Which drug should be given to a p.vivax malaria patient with deficient glucose 6-phosphate for prevention of relapse?

ANSWER

Unfortunately, primaquine is the only drug that is known to kill the latent liver stages of P. vivax and P. ovale. Since it can induce haemolysis in people with G6DP deficiency, this drug is usually not recommended for people with this deficiency. However, there are actually gradations of severity of G6DP deficiency, and so in some cases, primaquine at therapeutic doses may be tolerated by people with only mild G6DP deficiency, if they are carefully monitored for anaemia throughout the process. This may be preferable to no treatment, since no other known medication can prevent relapse.

Treatment for Malaria

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QUESTION:

What is the main medicine to cure malaria and about safety precautions?

ANSWER:

There are a number of medicines used to treat malaria. Traditionally, chloroquine has been the first line drug of choice for uncomplicated, non-resistant malaria. However, several types of malaria, and most notably Plasmodium falciparum, the most severe and deadly kind, has become resistant to chloroquine in many places. In some parts of south-east Asia, Plasmodium vivax has also begun to show worrying signs of chloroquine resistance. In such settings, where resistance to chloroquine is suspected, the first line medications for uncomplicated cases are artemisinin-based combination therapies (ACTs), such as Coartem.

The World Health Organization has recommended that artemisinin only be given in combination with another drug to prevent malaria also becoming resistant to this therapy as well. Cases of malaria which have progressed beyond the grasp of that treatable with oral medication as described above (so-called “complicated” cases, most common with P. falciparum infection) are usually given intravenous quinine as a first-line response.

All of these treatments have been rigorously tested in strictly controlled clinical and field trials, and while they may have side effects, they are generally mild and in most cases, the patient will be given the dose without prior testing for reaction to the drug. One exception is with primaquine, which is sometimes used as a preventative medication against malaria and can also be used to treat the liver stages of P. vivax and P. ovale. Primaquine is known to cause severe haemolysis in people with G6DP deficiency, and so people with a high statistical probability of having this condition (for example due to family history or ethnicity) should be tested prior to being given primaquine.

G6PD and Malaria

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QUESTION:

Does one need to have a normal result in G6PD screening before he can take Malarial pills?

ANSWER:

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.