The reality of using primaquine

Abstract

Background: Primaquine is currently the only medication used for radical cure of Plasmodium vivax infection. Unfortunately, its use is not without risk. Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency have an increased susceptibility to haemolysis when given primaquine. This potentially fatal clinical syndrome can be avoided if patients are tested for G6PD deficiency and adequately informed before being treated.

Case presentation: A 35-year old male presented to our clinic on the Thai-Burmese border with a history and clinical examination consistent with intravascular haemolysis. The patient had been prescribed primaquine and chloroquine four days earlier for a P. vivax infection. The medication instructions had not been given in a language understood by the patient and he had not been tested for G6PD deficiency. The patient was not only G6PD deficient but misunderstood the instructions and took all his primaquine tablets together. With appropriate treatment the patient recovered and was discharged home a week later.

Conclusions: Whilst primaquine remains the drug of choice to eradicate hypnozoites and control P. vivax transmission, the risks associated with its use must be minimized during its deployment. In areas where P. vivax exists, patients should be tested for G6PD deficiency and adequately informed before administration of primaquine.

Figure 1

A sample of the patient's urine at admission. The black colour of the urine is due to the presence of haemoglobinuria.

Figure 2

Electrophoresis gel confirming the patient to be hemizygote for Mahidol variant of G6PD deficiency. From the left side. Line 1: Molecular marker 100 bp; L2: Mahidol hemizygote; L3 Patient sample; L4:G6PD normal; L5: G6PD normal/Mahidol heterozygote; L6: molecular marker 25 bp.