P. vivax or P. ovale Malaria with G6PD Activity ≥70% of Normal: Preventing Relapse

Patients with P. vivax or P. ovale malaria face a meaningful risk of relapse because dormant liver-stage parasites (hypnozoites) persist after the blood-stage illness resolves. When G6PD activity is confirmed at or above 70% of normal, a specific anti-relapse strategy becomes available that would otherwise be contraindicated.

Clinical Scenario

This protocol applies to patients with uncomplicated P. vivax or P. ovale malaria whose G6PD activity is ≥70% of normal (classified as G6PD normal). Confirming this threshold is a prerequisite before initiating the anti-relapse regimen described here.

Treatment Approach (partial summary)

With G6PD activity confirmed at the normal threshold, relapse prevention can be achieved with either a single-dose antiparasitic option taken alongside chloroquine, or a multi-day high-dose course — selection depends on patient age, weight, and clinical context. Full regimen details, dosing guidance, and patient-specific considerations are available in the complete protocol.

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References

If the patient has G6PD activity >70%, tafenoquine as single dose tafenoquine or high dose primaquine (1 mg/kg/day for 7 days or 0.5 mg/kg daily for 14 days) can be given.

The primaquine high dose (7 mg/kg) should be provided at 1 mg/kg/day for 7 days only to patients with ≥70% G6PD activity.

Tafenoquine is recommended as an alternative to primaquine (3.5 mg/kg total dose) for preventing relapses of P. vivax in patients ≥2 years of age, who have ≥70% G6PD activity and who receive chloroquine treatment.

Adults, adolescents and children weighing more than 35 kg: the administration of a single 300 mg dose (two 150 mg tafenoquine tablets) is recommended on Day 1 or Day 2 of the 3-day course of chloroquine.

To prevent relapse, children and adults (except pregnant women, infants aged <1 month and women breastfeeding infants aged <1 month, and people with G6PD deficiency), primaquine should be given at a high total dose (7 mg/kg) at 0.5 mg/kg/day for 14 days or 1 mg/kg/day for 7 days for prevention of relapses in patients with uncomplicated P. vivax or P. ovale malaria.

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