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Combination of
Sulfadoxine Sulfonamide
Pyrimethamine Antiparasitic
Clinical data
Trade names Fansidar
License data
  • AU: C
  • US: C (Risk not ruled out)
Routes of
Legal status
Legal status
  • AU: S4 (Prescription only)
  • UK: POM (Prescription only)
  • US: ℞-only
ATC code P01BD51 (WHO)

Sulfadoxine/pyrimethamine (Fansidar) is a combination antimalarial drug containing the sulfonamide antibiotic sulfadoxine and the antiprotozoal pyrimethamine.

It is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.[1]

Medical uses[edit]


It is approved by the United States' Food and Drug Administration for use as a treatment and preventive measure against malaria.[2] 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.[3] Due to side effects, however, it is no longer recommended as a routine preventive,[4] but only to treat serious malaria infections or to prevent them in areas where other drugs may not work.[5]


It has also be used as a treatment and prophylactic measure for toxoplasmosis and Pneumocystis jiroveci pneumonia.[6][7][8][9][10][11]

Adverse effects[edit]

Adverse effects by incidence include:[2][6][12][13]

Common (>1% frequency):

  • Hypersensitivity reactions (e.g. itchiness, contact dermatitis, and hives)
  • Myelosuppression
  • Gastrointestinal effects (e.g. nausea, vomiting, and diarrhoea)
  • Headache

Rare (<1% frequency):

Unknown frequency:

  • Abnormal liver function test results (e.g. elevated serum ALT, AST, alkaline phosphatase, and bilirubin concentrations)


Use of this drug is contraindicated in:[2][12]

  • Megaloblastic anaemia caused by folate deficiency
  • Hypersensitivity to pyrimethamine, sulfonamides, or any ingredient in the formulation
  • Repeated prophylactic (prolonged) use in patients with kidney or liver failure or blood dyscrasias
  • Infants <2 months of age
  • Prophylaxis in pregnancy at term
  • Prophylaxis in nursing women
  • Acute porphyria


Sulfadoxine is a sulfonamide antibiotic that competes with p-aminobenzoic acid in the biosynthesis of folate.[2] Pyrimethamine serves as a selective inhibitor of protozoal dihydrofolate reductase, hence preventing the synthesis of tetrahydrofolate — the active form of folate.[2] A great degree of synergy occurs between the two drugs due to their inhibition of two different steps in the biosynthesis of tetrahydrofolate.[2]

Pharmacokinetic parameter Pyrimethamine Sulfadoxine
Half-life 111 hours 169 hours
Cmax 0.2 mg/l 60 mg/L
Tmax 4 hours 4 hours
Protein bound 87% 90%
Excretion Renal (16-30%) Renal (30%)
Metabolism Hepatic Hepatic

See also[edit]


  1. ^ "19th WHO Model List of Essential Medicines (April 2015)" (PDF). WHO. April 2015. Retrieved May 10, 2015. 
  2. ^ a b c d e f "Pyrimethamine, Sulfadoxine and Pyrimethamine Monograph for Professionals". Retrieved 9 January 2014. 
  3. ^ JAMA -Abstract: Sulfadoxine-Pyrimethamine, Chlorproguanil-Dapsone, or Chloroquine for the Treatment of Plasmodium vivax Malaria in Afghanistan and Pakistan: A Randomized Controlled Trial, May 23/30, 2007, Leslie et al. 297 (20): 2201.
  4. ^ Medical Treatment - Sulphadoxine and Pyrimethamine.
  5. ^ Pyrimethamine and Sulfadoxine (Oral Route) -
  6. ^ a b "Fansidar, Pyrimethamine-sulfadoxine (pyrimethamine/sulfadoxine) dosing, indications, interactions, adverse effects, and more". Medscape Reference. WebMD. Retrieved 9 January 2014. 
  7. ^ Bath, PM; Lillicrap, DA; Winter, M (June 1987). "Fansidar - a treatment for AIDS-related pneumocystis?" (PDF). Postgraduate Medical Journal. 63 (740): 509–510. doi:10.1136/pgmj.63.740.509-a. PMC 2428336free to read. PMID 3501583. 
  8. ^ 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. PMID 7994239. 
  9. ^ Bessesen, MT; Miller, LA; Cohn, DL; Bartlett, S; Ellison, RT 3rd (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. PMID 7756514. 
  10. ^ Michalová, K; Ríhová, E; Havlíková, M (July 1996). "[Fansidar in the treatment of toxoplasmosis]". Cesk Slov Oftalmol. (in Czech). 52 (3): 173–178. PMID 8768475. 
  11. ^ Schürmann, D; Bergmann, F; Albrecht, H; Padberg, J; Grünewald, T; Behnsch, M; Grobusch, M; Vallée, M; Wünsche, T; Ruf, B; Suttorp, N (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. PMID 11243747. 
  12. ^ a b Joint Formulary Committee (2013). British National Formulary (BNF) (65 ed.). London, UK: Pharmaceutical Press. p. 429. ISBN 978-0-85711-084-8. 
  13. ^ "FANSIDAR® (sulfadoxine and pyrimethamine)" (PDF). Roche Products Pty Limited. 17 April 2008. Retrieved 9 January 2014.