China
Africa
Explore chapters and articles related to this topic
The Challenge of Parasite Control
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Malarone® is not without side effects. Sleep disturbances are common, as are canker sores and headaches. Yet these are usually infrequent or mild enough that Malarone® is now widely used for malaria prophylaxis. Tafenoquine, one of the drugs recently approved by the FDA, is another drug useful for both prophylaxis and treatment of malaria. Because it can kill hyponozoites in the liver it is especially useful in preventing relapses typical in Plasmodium vivax infection. Its mode of action remains unclear, but it appears to result in oxidative damage to parasite DNA. And because it has a longer half-life than primaquine, previously the only available drug to destroy hypnozoites, only a single dose is required. This is an important consideration in prophylaxis, in that the time during which side effects may occur is considerably shortened.
Treatment and prevention of malaria
Published in David A Warrell, Herbert M Gilles, Essential Malariology, 2017
David A Warrell, William M Watkins, Peter A Winstanley
Tafenoquine is an 8-aminoquinoline drug developed by the US Army Program (Peters, 1999). It is a 5-phenoxy derivative of primaquine with a longer elimination half-life (14 days compared to 6 hours) and, in animal models, is seven times more active than primaquine as a hypnozoitocide, 14 times more active as a causal prophylactic and 100 times more active as a blood schizontocide. It is better tolerated than primaquine, but can cause haemolysis in people with G6PD deficiency. Tafenoquine has great potential as a causal prophylactic drug against P. falciparum, for the radical cure of P. vivax, as a gametocytocidal and possibly blood schizontocidal drug for P. falciparum.
Tafenoquine
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
Tafenoquine has been used in combination with chloroquine as treatment for acute vivax malaria. Two Australian soldiers were successfully treated with 800 mg of tafenoquine given over 3 days for acute vivax malaria, with parasite clearance from the blood occurring by day 4 (Nasveld and Kitchener, 2005). Twenty-seven additional soldiers received an initial 3-day course of chloroquine followed by a 3-day course of tafenoquine (200 mg daily), then by 200 mg weekly for 8 weeks (Kitchener et al., 2007). Only 1 of the 27 soldiers (3.7%) relapsed after 6 months of observation in Australia.
Antimalarial drugs for treating and preventing malaria in pregnant and lactating women
Published in Expert Opinion on Drug Safety, 2018
Makoto Saito, Mary Ellen Gilder, Rose McGready, François Nosten
Current WHO guidelines caution against primaquine use in breastfeeding women during the first 6 months postpartum, and at any time for women breastfeeding G6PD deficient infants and young children due to lack of data on breast milk excretion. Subsequently, one study of 21 G6PD normal lactating women breastfeeding G6PD normal infants 28 days and older found extremely low levels of primaquine the breastmilk correlating with a RID of 0.6% [159]. Total cumulative infant drug exposure over 14 days of treatment was estimated to be 0.042 mg/kg, and no adverse effects of the medication were seen. The authors conclude that, considering that primaquine-induced hemolysis is dose-dependent, these extremely low doses are very unlikely to cause harm, even in G6PD deficient infants [159]. Data are still needed in the first month of life to determine excretion in colostrum and transitional milk, though theoretical exposure during this period is low as breast milk volumes ingested by the infant in the first week of life are considerably smaller than those consumed later. Studies are needed to assess the safety of tafenoquine during breastfeeding.
The prodrug approach in the era of drug design
Published in Expert Opinion on Drug Delivery, 2019
As per November 2018, three prodrugs have been approved; tafenoquine, and fosnetupitant. Baloxavir marboxil (2 in Figure 1) is a novel agent with a novel mechanism of action. It is indicated for the treatment of influenza A and B and given as a single dose during the first 48 h hours of influenza symptoms. It inhibits viral shedding through the inhibition of viral CAP endonuclease. Tafenoquine (3 in Figure 1) is an 8-aminoquinoline analog of primaquine indicated for the treatment of malaria. Fosnetupitant (4 in Figure 1) is the prodrug form of netupitant and one of the active ingredients in Akynzeo, a drug approved for the treatment of acute and delayed nausea due to chemotherapy. It is dephosphorylated by plasma phosphatase to produce the active form.
Tafenoquine: a toxicity overview
Published in Expert Opinion on Drug Safety, 2021
Although this review focused on the safety and tolerability of tafenoquine, outstanding questions remain about the role of tafenoquine in malaria case management, prevention, and elimination. In malaria-endemic parts of SE Asia, South America, and Oceania, the efficacy of higher single doses of tafenoquine should be compared to the currently recommended 300 mg dose so that relapse prevention can be optimized. In addition, more studies assessing schizonticidal combinations with tafenoquine other than chloroquine are needed especially in areas with chloroquine resistant P. vivax. Formal recommendations for tafenoquine radical cure dosing in children <16 years old are anticipated and will need continued evaluation.