A prospective study evaluating the efficacy of a single, 45-mg dose of primaquine, as a gametocytocidal agent, in patients withPlasmodium falciparummalaria in Mumbai, India

Abstract

The efficacy of a single dose of 45 mg primaquine, as a gametocytocidal agent, was assessed in Mumbai, India, among adults with uncomplicated or severe Plasmodium falciparum malaria. All the patients investigated had been found gametocytaemic, with at least 56 gametocytes/microl blood, within the first 72 h of their illness. Those with uncomplicated malaria, like those with severe malaria, were randomized to receive or not receive primaquine. All the patients were followed up for 29 days post-admission, for gametocytaemia and gametocyte viability (as determined by exflagellation). Among those with uncomplicated malaria, six (27.3%) of the 22 who did not receive primaquine but only one (4.2%) of the 24 who did receive the drug, on day 4, remained gametocytaemic on day 29 (P < 0.05). Similarly, seven (31.8%) of the 22 severe cases who did not receive primaquine but only two (9.5%) of the 21 severe cases who received the drug, on day 8, were found gametocytaemic on day 15 (P < 0.05). While the single, 45-mg dose of primaquine recommended by the World Health Organization was effective in clearing gametocytes from the blood of > 90% of the present cases of malaria, > 4% of the patients with uncomplicated malaria and > 9% of those with the severe disease continued to harbour gametocytes in their peripheral blood 29 and 15 days after taking the primaquine, respectively.

Effect of Primaquine on Gametocyte Carriage in the Case-Management of Uncomplicated Falciparum Malaria with Acts: Nigerian Perspective

“…On the contrary, studies from Sudan and India showed reduced or no effect of PQ [29] [30]. These studies agree with Okell et al, who in a randomized controlled study also showed conclusively that a six-dose course of Artemether-Lumefantrine (co-artemether) given to children with P. falciparum malaria in Gambia reduces gametocyte prevalence, duration of gametocyte carriage, and infectiousness to mosquitoes [31].…”

Gametocitemia en malaria por Plasmodium falciparum tratada con amodiaquina o artesunato

“…Sobre la utilidad de la primaquina para controlar la gametocitemia de P. falciparum hay pocas dudas (24,(30)(31)(32)(33)(34)(35)(36)(37). La costumbre es darla en dosis única (0,75 mg/kg) al día siguiente de terminar el tratamiento esquizonticida, pero es poco claro el por qué de este tiempo, cuando podría y debería darse desde el primer día si lo que se quiere es controlar eficaz y rápidamente la gametocitemia.…”

“…La actividad esporonticida, aunque todavía controvertida, parece ser clara y potente (23)(24)(25)(26)(27)(28)(29) y algo similar sucede con los efectos sobre gametocitos de Plasmodium vivax y, sobre todo, de P. falciparum (24,(30)(31)(32)(33)(34)(35). El efecto de la primaquina sobre la viabilidad de los gametocitos inmaduros es desconocido, pero reduce intensamente la viabilidad de los maduros; el efecto neto de la primaquina sobre la capacidad de los gametocitos de P. falciparum para causar infección a los mosquitos es muy elevado (+++/+++) (36).…”

In Vitro Activities of Primaquine-Schizonticide Combinations on Asexual Blood Stages and Gametocytes of Plasmodium falciparum

“…In vivo studies conducted in Southeast Asia and Africa showed that PQ added to ACTs for treating P. falciparum malaria exhibited effective gametocyte clearance in patients (6)(7)(8)(9). Even when added to non-artemisinin-based regimens, PQ (Ͼ0.4 mg/kg) was able to drastically reduce the proportions of people with detectable gametocytemia (10)(11)(12)(13)(14).…”