Sulfadoxine/pyrimethamine, sold under the brand name Fansidar, is a combination medication used to treat malaria.[1][2] It contains sulfadoxine (a sulfonamide) and pyrimethamine (an antiprotozoal).[3] For the treatment of malaria it is typically used along with other antimalarial medication such as artesunate.[3] In areas of Africa with moderate to high rates of malaria, three doses are recommended during the second and third trimester of pregnancy.[4]
It is approved in the United States as a treatment and preventive measure against malaria.[6] The combination is considered to be more effective in treating malaria caused by Plasmodium falciparum than that caused by P. vivax, for which chloroquine is considered more effective, though in the absence of a species-specific diagnosis, the sulfadoxine-pyrimethamine combination may be indicated.[7] Due to side effects, however, it is no longer recommended as a routine preventive,[8] but only to treat serious malaria infections or to prevent them in areas where other drugs may not work.[9] However, it is recommended by the World Health Organization (WHO) for seasonal preventative use in children when combined with amodiaquine.[10]
Sulfadoxine is a sulfonamide antibiotic that competes with p-aminobenzoic acid in the biosynthesis of folate.[6] Pyrimethamine serves as a selective inhibitor of protozoal dihydrofolate reductase, hence preventing the synthesis of tetrahydrofolate — the active form of folate.[6] A great degree of synergy occurs between the two drugs due to their inhibition of two different steps in the biosynthesis of tetrahydrofolate.[6]
^World Health Organization (2015). The selection and use of essential medicines. Twentieth report of the WHO Expert Committee 2015 (including 19th WHO Model List of Essential Medicines and 5th WHO Model List of Essential Medicines for Children). Geneva: World Health Organization. hdl:10665/189763. ISBN9789241209946. ISSN0512-3054. WHO technical report series;994.
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^Foot AB, Garin YJ, Ribaud P, Devergie A, Derouin F, Gluckman E (August 1994). "Prophylaxis of toxoplasmosis infection with pyrimethamine/sulfadoxine (Fansidar) in bone marrow transplant recipients". Bone Marrow Transplantation. 14 (2): 241–245. PMID7994239.
^Bessesen MT, Miller LA, Cohn DL, Bartlett S, Ellison RT (March 1995). "Administration of pyrimethamine/sulfadoxine for prevention of Pneumocystis carinii pneumonia in patients with AIDS". Clinical Infectious Diseases. 20 (3): 730–731. doi:10.1093/clinids/20.3.730. PMID7756514.
^Michalová K, Ríhová E, Havlíková M (July 1996). "[Fansidar in the treatment of toxoplasmosis]". Ceska a Slovenska Oftalmologie (in Czech). 52 (3): 173–178. PMID8768475.
^Schürmann D, Bergmann F, Albrecht H, Padberg J, Grünewald T, Behnsch M, et al. (January 2001). "Twice-weekly pyrimethamine-sulfadoxine effectively prevents Pneumocystis carinii pneumonia relapse and toxoplasmic encephalitis in patients with AIDS". The Journal of Infection. 42 (1): 8–15. doi:10.1053/jinf.2000.0772. PMID11243747.