(Steffen et al., 1993). When used for prophylaxis, Fansidar can produce severe allergic reactions: in American travelers, Fansidar was linked to severe skin reactions (1 per 5,000 to 8,000 users) and mortality (1 per 11,000 to 25,000 users) (Miller et al., 1986). These adverse outcomes are not as frequent when a single dose of Fansidar is used for treatment. Concerns about sulfa drug use during pregnancy are outweighed by the known risks to mother and fetus of untreated malaria.
The latest antifol combination is chlorproguanil and dapsone, also known as Lapdap. This particular combination is inherently more effective than Fansidar (even in areas where resistance is present) and has a far shorter elimination time, which may decrease the likelihood of resistance (Watkins et al., 1997; Mutabingwa et al., 2001). On the other hand, its shorter half-life requires that Lapdap be given over 3 days rather than as SP’s one single dose.
TETRACYCLINE and derivatives such as doxycycline may be paired with other drugs for treatment or used as single agents for prophylaxis. In areas where quinine efficacy is diminished, tetracyclines are often added to quinine to improve cure rates. Tetracyclines are also used with shortened courses of quinine to decrease quinine-associated side effects. Tetracyclines are contraindicated in pregnant or breastfeeding women, or in children under age 8. Common side effects include nausea, vomiting, diarrhea, secondary yeast infections, and photosensitivity.
PRIMAQUINE, an 8-aminoquinoline, acts against malaria parasites in the liver, thereby reducing the likelihood of P. vivax or P. ovale relapse. Primaquine is also reasonably efficacious (74% efficacy against P. falciparum; 90 percent efficacy against P. vivax) when used for prophylaxis (Baird et al., 1995). Although it also has activity against blood-stage asexual parasites, drug concentrations that kill fully mature blood parasites are toxic. Primaquine is also a potent gametocidal drug, i.e., it kills the sexual stage of the malaria parasite infective to mosquitoes.
Primaquine can produce severe and potentially fatal hemolytic anemia in people with glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiencies. The most severe Mediterranean B variant and related Asian variants of G6PD deficiency occur at high rates among several groups and regions: Kurdish Jews (62 percent), Saudia Arabia (13 percent), Burma (20 percent), and southern China (6 percent) and have now spread through migration and intermarriage. Primaquine should not be used in pregnancy.
TAFENOQUINE, a synthetic analog of primaquine, is currently being tested. It is highly effective against both liver and blood stages of malaria. Because of its long half-life (14 days versus 6 hours for primaquine),