P. vivax patients are treated with 14-day primaquine under the Indian National Programme. Despite active pharmacovigilance by trained community health workers, patients reported no haemolytic side effects. We assessed drop in haemoglobin and recovery following supervised 14-day primaquine treatment for P. vivax radical cure.
In Odisha state, patients with confirmed P. vivax malaria, and haemoglobin of 7 g/dl or more were included in the study. Community health workers asked patients about haemolytic side effects before providing the daily dose of directly observed primaquine therapy for 14 days. Haemoglobin (Hb) was measured with haemocue on days 0, 3, 7, 28 and 42. Haemolytic adverse events or Hb drop of 2-3 gm were followed up by a health worker. Primaquine was discontinued in event of a fall of Hb of 3 g/dl or greater and patient was referred to hospital. G6PD status of the enrolled patients was determined after completion of study.
Of the 100 patients enrolled, Hb fall could be assessed in 99. Mean Hb fell from 11.7 to 11.3 g/dL by day 3 before increasing to 11.7 by day 7 and 12.2 g/dl by day 42. Two subjects had significant Hb drop of > 4 g/dL, one on days 7 and 14. Both patients recovered by day 42. Four subjects had a fall of more than 3 g/dL by day 14, and all recovered by day 42. No clinical haemolytic symptoms were observed in enrolled patients. Of the 100 enrolled patients, G6PD status was studied in 88, five were deficient. Hb fall of more than 3 g/dl was observed in two of them. The prevalence of G6PD deficiency in the study areas was 4.8%.
Preliminary analysis indicates that primaquine causes haemolytic anaemia in a fraction of patients. Further investigations are needed to understand G6PD status of the subjects.