G6PD and malaria: When Methylene Blue (MB) was used against malaria, significant haemoglobin drops in A- G6PD hemizygous and homozygous children were shown in West Africa using the gametocytocidal dose (15 mg/Kg per day for 3 days) but with limited clinical impact (Meissner et al., 2005; Muller et al., 2013).