naphthoquinones and halofantrine

Malaria is a major cause of pediatric mortality in sub-Saharan Africa. Worldwide estimates of mortality among children with Plasmodium falciparum malaria range from 1 to 2 million deaths per year. Management of malaria is increasingly difficult because of the global spread of drug-resistant strains of P. falciparum. There is an urgent need for safe and effective new therapies to treat multidrug-resistant malaria.. This open label, randomized trial compared atovaquone and proguanil hydrochloride with halofantrine for treatment of acute, uncomplicated P. falciparum malaria in children age 3 to 12 years (84 patients per group). Study drug dosages were adjusted by weight (approximately 20 and 8 mg/kg daily for three doses for atovaquone and proguanil hydrochloride and 8 mg/kg every 6 h for three doses for halofantrine). Patients were monitored by serial clinical and laboratory assessments for 28 days after starting treatment.. Both regimens were effective (cure rate, 93.8% for atovaquone and proguanil hydrochloride and 90.4% for halofantrine) and produced prompt defervescence. Mean parasite clearance times were 50.2 h for halofantrine and 64.9 h for atovaquone and proguanil hydrochloride. More adverse experiences were reported in children treated with halofantrine (119) than with atovaquone and proguanil hydrochloride (73).. In Kenyan children the combination of atovaquone and proguanil hydrochloride has efficacy comparable with that of halofantrine for treatment of acute uncomplicated multidrug-resistant falciparum malaria and is associated with a lower rate of adverse events.

Topics: Acute Disease; Animals; Antimalarials; Atovaquone; Child; Child, Preschool; Drug Therapy, Combination; Feces; Female; Humans; Malaria, Falciparum; Male; Naphthoquinones; Phenanthrenes; Plasmodium falciparum; Proguanil; Treatment Outcome

Blackwater fever is a clinical entity characterized by acute intravascular hemolysis classically occuring after the re-introduction of quinine in long-term residents in Plasmodium falciparum endemic areas and repeatedly using the product.. The symptomatology appears brutally with emission of porto-colored urine, icterus, pallor, nausea, fever and acute renal failure. The hemolytic-like anemia is immediately severe. Parasitemia is mild or absent. The mechanism of renal failure is tubular necrosis.. Well known at the start of the 20th century, blackwater fever has become exceptional since 1950, when quinine was replaced by chloroquine. The disease reappeared in 1990, following the re-utilization of quinine because of resistance to chloroquine. Thereafter, several cases have been described with halofantrine and mefloquine, two new molecules similar to quinine (amino-alcohol family). The physiopathogenesis of the disease is not well known, however it would appear that the concomitance of a double sensitivization of the red blood cells to the P. falciparum red blood cells and to the amino-alcohols is necessary to provoke the hemolysis.. The severity of the clinical picture often requires initial management in intensive care unit. Nowadays, however, prognosis is good and the disease usually regresses without after effects.

Topics: Adolescent; Adult; Aged; Antimalarials; Atovaquone; Blackwater Fever; Critical Care; Diagnosis, Differential; Drug Combinations; Humans; Mefloquine; Middle Aged; Naphthoquinones; Phenanthrenes; Prognosis; Proguanil; Pyrimethamine; Quinine; Sulfadoxine

The gametocytocidal and sporontocidal activity of three 8-aminoquinolines (primaquine, WR-238605, and WR-242511), three dihydroacridine-diones (floxacrine, WR-250547, and WR-250548), a 1,4-naphthoquinone (menoctone), a synthetic aminoalcohol (halofantrine), and a guanide (WR-182393) was determined against a cloned line of Plasmodium berghei ANKA. Gametocytocidal activity was assessed by treating mice with a single intraperitoneal inoculation of a given compound (25 mg base drug/kg mouse body weight) four days after the mice were infected with P. berghei. Thin blood smears were made every other day, and the percent parasitemia and macrogametocyte and microgametocyte rates were determined. Floxacrine, menoctone, WR-242511, WR-250547, and WR-250548 effectively cleared sexual and asexual parasites from the peripheral circulation within six days of drug administration. Halofantrine, primaquine, WR-182393, and WR-238605 were ineffective at clearing P. berghei ANKA from circulating erythrocytes at the doses tested; however, mice survival time increased markedly with these compounds when compared with the controls. Significant numbers of macrogametocytes and microgametocytes were present throughout the duration of the infection in mice treated with halofantrine, primaquine, WR-182393, and WR-238605. Sporontocidal activity was evaluated by allowing Anopheles stephensi mosquitoes to feed on P. berghei-infected mice 90 min after treatment with a particular drug. Halofantrine and WR-182393 exhibited no sporontocidal activity, while floxacrine, menoctone, primaquine, WR-238605, WR-242511, WR-250547, and WR-250548 exhibited significant activity. Minimum effective doses (mg base drug/kg of mouse body weight) that prevented mosquitoes from developing sporozoite-infected salivary glands were 0.1563 mg/kg for WR-250547, 0.625 mg/kg for menoctone, 1.25 mg/kg for primaquine, 10 mg/kg for floxacrine, 10 mg/kg for WR-242511, 10 mg/kg for WR-250548, and 25 mg/kg for WR-238605.

Topics: Acridines; Aminoquinolines; Analysis of Variance; Animals; Anopheles; Antimalarials; Female; Germ Cells; Guanidines; Imidazoles; Mice; Mice, Inbred ICR; Naphthoquinones; Phenanthrenes; Plasmodium berghei; Primaquine

Topics: Aminoquinolines; Amodiaquine; Antimalarials; Artemisinins; Calcium Channel Blockers; Chloroquine; Humans; Malaria; Mefloquine; Naphthoquinones; Phenanthrenes; Primaquine; Quinine; Sesquiterpenes; Sulfadoxine