Sulfadoxine

Pronunciation: sul-fa-DOX-een.

Generic name
sulfadoxine
Brand names
Fansidar (historical, combined with pyrimethamine; discontinued/cancelled in the reference markets reviewed)
Drug class
Antimalarial sulfonamide (long-acting sulfonamide antifolate), almost always used combined with pyrimethamine
Form
Tablet (historically 500 mg sulfadoxine / 25 mg pyrimethamine, combined in a single tablet)
Route
Oral
Legal status
Prescription-only where available; the branded combination product is discontinued or unconfirmed as currently marketed in the United States, United Kingdom, European Union, Canada, Australia, and New Zealand.

Availability and supply rules vary by country

Trade names by country: United States · Canada · Australia

Australia: Fansidar (3) · Full directory

What sulfadoxine is and how it works

Sulfadoxine is an antimalarial sulfonamide medicine, almost always combined with pyrimethamine, used to treat or help prevent malaria caused by Plasmodium falciparum. The combination has historically been sold as Fansidar. (1) (7)

This medicine is not currently available as a marketed branded product in the United States, United Kingdom, European Union, Canada, Australia, or New Zealand -- the historical brand Fansidar has been discontinued or its current market status could not be confirmed in each of these countries. Sulfadoxine-pyrimethamine remains in real, current use in malaria-endemic regions (chiefly in Africa), including as a World Health Organization-recommended option for treating malaria and, at a supervised full therapeutic dose, for preventing malaria in pregnancy. It carries a serious, real risk of fatal skin reactions and must only be used under clinical or public-health-program supervision.

Mechanism of action: how sulfadoxine works

Sulfadoxine is a long-acting sulfonamide that inhibits dihydropteroate synthase, blocking folate synthesis in malaria parasites; combined with pyrimethamine (a dihydrofolate reductase inhibitor acting on a later step of the same pathway), the two drugs act synergistically against Plasmodium falciparum. (1)

What sulfadoxine is used for

Treatment of uncomplicated Plasmodium falciparum malaria

Used, combined with pyrimethamine, to treat acute uncomplicated malaria caused by Plasmodium falciparum, historically when resistance to chloroquine was suspected. This remains a current WHO-recognised treatment option in some malaria-endemic settings. (1)

Intermittent preventive treatment of malaria in pregnancy (IPTp)

The World Health Organization currently recommends sulfadoxine-pyrimethamine, given at a full therapeutic dose at least 4 weeks apart starting in the second trimester, as intermittent preventive treatment for pregnant people in areas of moderate-to-high malaria transmission (chiefly in Africa), as part of a supervised antenatal care program. (7)

Historical short-term travel malaria prophylaxis (largely discontinued use)

Sulfadoxine-pyrimethamine was previously used for short-term prevention of chloroquine-resistant malaria in travellers, but this use was largely abandoned because of the risk of severe, sometimes fatal, skin reactions, and it is no longer generally recommended for this purpose. (1) (4)

Before taking sulfadoxine

Do not take / not appropriate for

  • Do not take sulfadoxine-pyrimethamine if you have a known allergy to sulfonamide medicines or to pyrimethamine. (all countries) (1)
  • Do not take sulfadoxine-pyrimethamine if you have megaloblastic anaemia caused by folate deficiency. (all countries) (1)
  • This combination is not used in infants younger than 2 months of age. (infants) (1)
  • It was historically contraindicated for preventive (prophylactic) use in pregnant people at term and in breastfeeding mothers. This is separate from the supervised, full-therapeutic-dose use for intermittent preventive treatment in pregnancy that the World Health Organization currently recommends earlier in pregnancy in malaria-endemic regions -- these are different treatment contexts, and either way this medicine should only be used in pregnancy under direct clinical or antenatal-program supervision. (pregnancy and breastfeeding) (1) (7)
  • Caution is needed with repeated dosing in people with significant kidney or liver impairment, or a history of blood cell disorders (blood dyscrasias) -- your prescriber will assess whether this medicine is appropriate. (renal or hepatic impairment, blood disorders) (1)

Tell your clinician about

  • Any personal or family history of severe skin reactions to medicines, or any sulfonamide allergy.
  • Whether you have glucose-6-phosphate dehydrogenase (G6PD) deficiency, since this medicine can trigger red blood cell breakdown (hemolysis) in this condition.
  • Any kidney or liver problems, or blood cell disorders.
  • Pregnancy, plans for pregnancy, or breastfeeding.
  • All other medicines you take, especially other sulfonamide medicines, trimethoprim combinations, or chloroquine.
(1)

How to take sulfadoxine

  • Take exactly as directed by your prescriber or the antenatal/malaria-treatment program supervising your care -- there is no universal fixed dose for everyone.
  • This medicine is taken by mouth, combined with pyrimethamine in the same tablet.
  • Complete the full course exactly as directed, even if you feel better, unless your clinician tells you otherwise.
(1) (7)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2) (3) (4) (5) (6) (7)

Missed dose

Contact your prescriber or the clinic/program supervising your treatment for specific guidance if you miss a dose, since dosing schedules for malaria treatment or preventive treatment in pregnancy are specific and time-sensitive.

Overdose

Seek urgent medical attention if an overdose is suspected, particularly for any skin rash, unusual bruising or bleeding, fever, sore throat, or signs of severe illness, since these can signal a serious blood or skin reaction. (1)

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms.

Stomach pain or a feeling of fullness.

What to notice: Stomach pain or a feeling of fullness.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Headache and dizziness.

What to notice: Headache and dizziness.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Nausea, vomiting, diarrhoea, and reduced appetite.

What to notice: Nausea, vomiting, diarrhoea, and reduced appetite.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Hair loss, muscle weakness, mood changes, nervousness, ringing in the ears (tinnitus), and trouble sleeping.

What to notice: Hair loss, muscle weakness, mood changes, nervousness, ringing in the ears (tinnitus), and trouble sleeping.

What to do: Discuss persistent or troublesome symptoms with the treating clinician or pharmacist. (1)

Serious warnings

Signs of a severe skin reaction (Stevens-Johnson syndrome or toxic epidermal necrolysis) — boxed_warning

Symptoms: Any new skin rash, blistering, peeling skin, mouth or eye sores, or flu-like illness with a rash.

Action: Seek emergency medical care immediately and contact the prescriber at the very first sign of a rash -- a clinician must assess this urgently, since fatalities have occurred with this reaction. (1)

Signs of a blood cell disorder (blood dyscrasia) — emergency

Symptoms: Unusual bruising or bleeding, persistent sore throat, fever, or unusual tiredness.

Action: Seek prompt medical attention; a clinician will check your blood counts and decide whether treatment needs to be adjusted. (1)

Signs of hemolysis (red blood cell breakdown), especially in G6PD deficiency — high caution

Symptoms: Unusual fatigue, pale skin, yellowing of the skin or eyes, or dark urine.

Action: Seek prompt medical attention; tell your prescriber if you know you have G6PD deficiency before starting treatment. (1)

Signs of a serious allergic reaction — emergency

Symptoms: Swelling of the face, lips, tongue, or throat; difficulty breathing; widespread hives.

Action: Seek emergency medical help immediately. (1)

Interactions

  • Chloroquine, when combined, can increase the risk of adverse reactions -- your clinician will manage this combination carefully if used. (1)
  • Other sulfonamide medicines or trimethoprim-containing combinations should generally be avoided during preventive (prophylactic) use, since their antifolate effects can add together. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Historic labeling contraindicated preventive use in pregnant people at term. Separately, the World Health Organization currently recommends supervised, full-therapeutic-dose intermittent preventive treatment starting in the second trimester in malaria-endemic regions, as part of an antenatal care program. These are different treatment contexts -- any use in pregnancy should only occur under direct clinical or antenatal-program supervision. (1) (2) (3) (4) (5) (6) (7)

Breastfeeding

Historic labeling advised against preventive use while breastfeeding. Discuss any need for treatment during breastfeeding with your prescriber. (1) (2) (3) (4) (5) (6) (7)

Children

Not used in infants younger than 2 months. Pediatric dosing for older infants and children is weight-based and clinician-directed. (1) (2) (3) (4) (5) (6) (7)

Elderly

No specific age-based dose adjustment is described in the source reviewed; individual monitoring for skin reactions and blood counts applies regardless of age. (1) (2) (3) (4) (5) (6) (7)

Hepatic_impairment

Caution advised with repeated dosing in significant liver impairment -- discuss with your prescriber. (1) (2) (3) (4) (5) (6) (7)

Renal_impairment

Caution advised with repeated dosing in significant kidney impairment -- discuss with your prescriber. (1) (2) (3) (4) (5) (6) (7)

Monitoring

Before starting

  • Assessment for sulfonamide/pyrimethamine allergy
  • G6PD status where relevant
  • Baseline blood counts where repeated dosing is planned
  • Pregnancy status and gestational age if applicable

During treatment

  • Watching closely for any new skin rash, mouth/eye sores, or blistering -- report immediately.
  • Blood count monitoring with repeated or prophylactic dosing.
  • Watching for signs of hemolysis, especially in G6PD-deficient individuals.
  • Program-directed follow-up dosing intervals for intermittent preventive treatment in pregnancy.
(1) (7)

Storage

Store at room temperature, protected from moisture and light, as directed on the product packaging supplied by the treating clinic or program, since this varies by manufacturer and country where it remains available.

Study the drug class: Sulfonamides

Professional information

Clinician-facing context only, drawn from the historic FDA-approved Fansidar label (product now discontinued in the US) and current WHO guidance for intermittent preventive treatment in pregnancy. This product is not currently marketed in the 6 standard reference markets reviewed for this page; verify current national/WHO guidance and local product information before prescribing.

Historical United States labeling

Indication: Treatment and short-term prophylaxis of chloroquine-resistant P. falciparum malaria

Dose summary: Treatment: single dose of 2-3 tablets (500 mg sulfadoxine/25 mg pyrimethamine each), often with another antimalarial. Prophylaxis (largely discontinued use): 1 tablet weekly or 2 tablets every 2 weeks, starting 1-2 days before travel and continuing 4-6 weeks after return. Pediatric: weight-based.

Renal context: Caution with repeated dosing in significant renal impairment; not further quantified in the source reviewed. (1)

WHO IPTp-SP guidance (malaria-endemic regions)

Indication: Intermittent preventive treatment of malaria in pregnancy

Dose summary: Full therapeutic dose given at least 3 times, at least 4 weeks apart, starting in the second trimester, in areas of moderate-to-high malaria transmission, as part of a supervised antenatal care program.

Renal context: Not detailed in the source reviewed for this dossier. (7)

Mechanism of action

Hepatic guidance

Use with caution in patients with significant hepatic impairment, particularly with repeated dosing; monitor closely.

Overdose note

Overdose management should focus on monitoring for and managing severe skin reactions, blood dyscrasias, and hemolysis; manage per local poison-control and toxicology guidance, since specific antidote data were not detailed in the source reviewed. (1)

Frequently asked questions

Is Fansidar (sulfadoxine-pyrimethamine) still available in the US, UK, Europe, Canada, Australia, or New Zealand?

No branded product was confirmed as currently marketed in any of these 6 countries at the time this page was written. It is confirmed cancelled/discontinued in the United States, Canada, and Australia, and no current UK, EU, or New Zealand regulator record could be found. It remains a real, current WHO-recommended medicine for malaria treatment and for preventing malaria in pregnancy in malaria-endemic regions, chiefly in Africa, under clinical/program supervision. (1) (2) (3) (4) (5) (6) (7)

Why does sulfadoxine-pyrimethamine have a boxed warning?

Because fatal cases of Stevens-Johnson syndrome and toxic epidermal necrolysis -- severe, blistering skin reactions -- have occurred with this medicine, particularly with repeated preventive dosing. Any new rash must be assessed by a clinician immediately. (1)

Can sulfadoxine-pyrimethamine be used in pregnancy?

This depends entirely on the clinical context. Historic labeling contraindicated its use for prevention in pregnant people at term, but current World Health Organization guidance recommends a supervised, full-therapeutic-dose regimen starting in the second trimester as part of an antenatal malaria-prevention program in endemic regions. Any use in pregnancy must be directed by a qualified clinician or antenatal program, never self-initiated. (1) (7)

What is the mechanism of action of sulfadoxine?

Sulfadoxine is a long-acting sulfonamide that inhibits dihydropteroate synthase, blocking folate synthesis in malaria parasites; combined with pyrimethamine (a dihydrofolate reductase inhibitor acting on a later step of the same pathway), the two drugs act synergistically against Plasmodium falciparum. (1)

What is the generic name of Sulfadoxine?

The generic name is sulfadoxine. It is sold under brand names including Fansidar (historical, combined with pyrimethamine; discontinued/cancelled in the reference markets reviewed). (1)

What class of drug is sulfadoxine?

Sulfadoxine is classed as: Antimalarial sulfonamide (long-acting sulfonamide antifolate), almost always used combined with pyrimethamine. (1)

References

  1. FANSIDAR (sulfadoxine and pyrimethamine) tablets -- FDA-approved labelingU.S. Food and Drug Administration, approved prescribing information (historical, product now discontinued in the US) · United States · accessed 2026-07-30 · source 1
  2. Fansidar Tablets -- Health Canada Drug Product Database entryHealth Canada Drug Product Database (DPD) · Canada · accessed 2026-07-30 · source 2
  3. Fansidar -- historical Australian product information; not currently listed on the ARTGTherapeutic Goods Administration (TGA), Australia -- historical Roche product information and current ARTG status check · Australia · accessed 2026-07-30 · source 3
  4. Fansidar -- no current UK emc Summary of Product Characteristics found; UK malaria prevention guidance no longer recommends itUK clinical/travel-medicine guidance (historical Roche UK product; no current emc SmPC listing found) · United Kingdom · accessed 2026-07-30 · source 4
  5. No current EMA-centralised authorisation record found for Fansidar/sulfadoxine-pyrimethamineEuropean Medicines Agency (EMA) -- search attempt only, no centralised EU authorisation record found · European Union · accessed 2026-07-30 · source 5
  6. No Medsafe data sheet or registration record for Fansidar/sulfadoxine-pyrimethamine could be locatedMedsafe (New Zealand regulator) -- search attempt only, no confirmed record found · New Zealand · accessed 2026-07-30 · source 6
  7. WHO policy and field guidance on intermittent preventive treatment of malaria in pregnancy with sulfadoxine-pyrimethamine (IPTp-SP); WHO Model List of Essential Medicines listing for sulfadoxine + pyrimethamineWorld Health Organization (WHO) · Global / malaria-endemic regions (chiefly sub-Saharan Africa) · accessed 2026-07-30 · source 7

Brand names by country

Single-ingredient sulfadoxine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

  • Fansidar (1)FDA approved 1981 now discontinued not currently marketed · 500 mg sulfadoxine / 25 mg pyrimethamine · F. Hoffmann-La Roche (historical)

Canada

  • Fansidar (2)Health Canada DPD cancelled post market 2000-07-27 confirmed · 500 mg sulfadoxine / 25 mg pyrimethamine, DIN 00692719 · Hoffmann-La Roche Limited

Australia

  • Fansidar (3)historical Roche registration not currently on ARTG · 500 mg sulfadoxine / 25 mg pyrimethamine · Roche Products (historical)
View brands in additional countries.

This page provides general reference information about sulfadoxine (combined with pyrimethamine) and is not a substitute for advice from the prescriber or public-health program managing your treatment. This medicine is not currently available as a marketed branded product in the United States, United Kingdom, European Union, Canada, Australia, or New Zealand; all dosing and treatment decisions should be made with a qualified clinician or the antenatal/malaria-treatment program supervising your care.

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