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Pyrimethamine / sulfadoxine Side Effects

Medically reviewed by Drugs.com. Last updated on Jan 15, 2024.

Applies to pyrimethamine / sulfadoxine: oral tablet.

Warning

Do not use this medication if you have ever had a serious allergic reaction to pyrimethamine or sulfadoxine. Stop taking the medicine and call your doctor at once if you have any signs of skin rash, no matter how mild.

You should not use this medication if you are allergic to sulfa drugs, or if you have liver or kidney disease (if using the medication long-term), a blood cell disorder (such as anemia), if you are in late pregnancy, or if you are breast-feeding a baby.

Take the pyrimethamine and sulfadoxine tablet after a meal, with plenty of water or other fluid. Swallow the tablet whole, do not break or chew it.

Drink plenty of water to keep your kidneys working and prevent kidney stones while taking this medication.

You should not take pyrimethamine and sulfadoxine for longer than 2 years without a doctor's advice.

In addition to taking pyrimethamine and sulfadoxine, use protective clothing, insect repellents, and mosquito netting around your bed to further prevent mosquito bites that could cause malaria.

No medication is 100% effective in treating or preventing malaria. For best results, keep using the medication as directed. Talk with your doctor if you have fever, vomiting, or diarrhea during your treatment.

Get emergency medical help if you have any of these signs of an allergic reaction while taking pyrimethamine / sulfadoxine: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using pyrimethamine and sulfadoxine and call your doctor at once if you have any of these serious side effects:

Less serious side effects of pyrimethamine / sulfadoxine may include:

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

For Healthcare Professionals

Applies to pyrimethamine / sulfadoxine: oral tablet.

Hypersensitivity

Severe cutaneous reactions have occurred in patients who have taken as few as two doses of pyrimethamine-sulfadoxine. The risk of fatal cutaneous reactions in patients receiving pyrimethamine-sulfadoxine has been estimated to range from 1 in 11,000 to 1 in 25,000. In general, the use of sulfonamide antibiotics is associated with large increases in the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis, although these phenomena are rare as a whole.[Ref]

Hypersensitivity reactions have included erythema multiforme, Stevens-Johnson syndrome, generalized skin eruptions, toxic epidermal necrolysis, urticaria, serum sickness, pruritus, exfoliative dermatitis, anaphylactoid reactions, periorbital edema, conjunctival and scleral injection, photosensitization, arthralgia, and allergic pericarditis. Fatalities due to severe hypersensitivity reactions have been reported.[Ref]

Dermatologic

Dermatologic side effects have frequently included phototoxicity, rash, dermatitis, and hair loss.[Ref]

Hematologic

Hematologic toxicity is more common with higher doses of pyrimethamine.

Many cases of agranulocytosis have occurred during therapy with pyrimethamine-dapsone, although it has been reported in patients receiving pyrimethamine-sulfadoxine as well.[Ref]

Hematologic side effects have included leucopenia (7%), agranulocytosis, aplastic anemia, megaloblastic anemia, thrombocytopenia, hemolytic anemia, purpura, hypoprothrombinemia, methemoglobinemia, and eosinophilia. Macrocytic anemia has also been reported. Fatalities have been reported.[Ref]

Gastrointestinal

Gastrointestinal side effects have included anorexia (5.5%), digestive intolerance (3%), diarrhea (2.74%), abdominal pain (2.74%), vomiting (2.74%), nausea, glossitis, stomatitis, and pancreatitis.[Ref]

Hepatic

Hepatic side effects have included hepatitis (7%), hepatocellular necrosis, and liver enzyme elevations.[Ref]

In many cases, the hepatitis has accompanied severe cutaneous reactions, fever, myalgias and arthralgias. Granulomas and necrosis have been seen on biopsy.[Ref]

Renal

Renal side effects have included renal failure, interstitial nephritis, toxic nephrosis with oliguria and anuria, crystalluria, and increases in BUN and serum creatinine.[Ref]

Respiratory

Respiratory side effects have included cough (9.6%), pulmonary infiltrates and shortness of breath which may be due to pulmonary hypersensitivity reactions. Frequently, the pulmonary reactions have accompanied other systemic symptoms.[Ref]

Nervous system

Nervous system side effects have included headache (4.1%), peripheral neuritis, mental depression, convulsions, ataxia, hallucinations, tinnitus, vertigo, insomnia, apathy, fatigue, muscle weakness, nervousness, and polyneuritis.[Ref]

Metabolic

Metabolic side effects associated with sulfonamides have included diuresis and hypoglycemia. Sulfonamides are chemically similar to goitrogenic agents (i.e., diuretics and oral hypoglycemic agents).[Ref]

Genitourinary

Genitourinary side effects have included crystalluria.[Ref]

Endocrine

Endocrine side effects including weight gain (1 kg or greater) have been reported in 53% of patients.

Other

Other side effects have included drug fever, chills, periarteritis nodosa, and lupus erythematosus phenomenon.[Ref]

References

1. Product Information. Fansidar (pyrimethamine-sulfadoxine). Roche Laboratories. 2022.

2. Roujeau JC, Kelly JP, Naldi L, et al. Medication use and the risk of Stevens-Johnson syndrome or toxic epidermal necrolysis. N Engl J Med. 1995;333:1600-7.

3. Zitelli BJ, Alexander J, Taylor S, Miller KD, Howrie DL, Kuritsky JN, Perez TH, Van Thiel DH. Fatal hepatic necrosis due to pyrimethamine-sulfadoxine (Fansidar). Ann Intern Med. 1987;106:393-5.

4. Selby CD, Ladusans EJ, Smith PG. Fatal multisystemic toxicity associated with prophylaxis with pyrimethamine and sulfadoxine (Fansidar). Br Med J (Clin Res Ed). 1985;290:113-4.

5. Murphy RL, Phair JP. Systemic reaction to pyrimethamine-sulfadoxine. J Fam Pract. 1986;22:375-6.

6. Phillips-Howard PA, West LJ. Serious adverse drug reactions to pyrimethamine-sulphadoxine pyrimethamine-dapsone and to amodiaquine in Britain. J R Soc Med. 1990;83:82-5.

7. Whitfield D. Presumptive fatality due to pyrimethamine-sulfadoxine. Lancet. 1982;2:1272.

8. Olsen VV, Loft S, Christensen KD. Serious reactions during malaria prophylaxis with pyrimethamine- sulfadoxine. Lancet. 1982;2:994.

9. Phillips-Howard PA, Behrens RH, Dunlop J. Stevens-Johnson syndrome due to pyrimethamine / sulfadoxine during presumptive self-therapy of malaria. Lancet. 1989;2:803-4.

10. Fansidar-associated fatal reaction in an HIV-infected man. MMWR Morb Mortal Wkly Rep. 1988;37:571-2.

11. Hornstein OP, Ruprecht KW. Fansidar-induced Stevens-Johnson Syndrome. N Engl J Med. 1982;307:1529-30.

12. Jeffrey RF. Transient lupus anticoagulant and fansidar therapy. Postgrad Med J. 1986;62:893-4.

13. Adams SJ, Broadbent J, Clayden LM, Ridley CM. Erythema multiforme (Stevens-Johnson) precipitated by Fansidar. Postgrad Med J. 1985;61:263-4.

14. Ward DJ, Krzeminska EC, Tanner NS. Treatment of toxic epidermal necrolysis and a review of six cases. Burns. 1990;16:97-104.

15. Ortel B, Sivayathorn A, Honigsmann H. An unusual combination of phototoxicity and Stevens-Johnson syndrome due to antimalarial therapy. Dermatologica. 1989;178:39-42.

16. Bamber MG, Elder AT, Gray JA, Minns RA. Fatal Stevens-Johnson syndrome associated with Fansidar and chloroquine. J Infect. 1986;13:31-3.

17. Ree GH. Chemoprophylaxis of malaria in Africa. Br Med J (Clin Res Ed). 1983;286:562.

18. Nicholls MD, Concannon AJ. Maloprim-induced agranulocytosis and red-cell aplasia. Med J Aust. 1982;2:564-6.

19. Booth F, Barker LC, Barton CJ, Naik RB. Agranulocytosis during malaria prophylaxis with Maloprim (pyrimethamine and dapsone). Postgrad Med J. 1984;60:566-7.

20. Bowcock SJ, Linch DC, Machin SJ, Stewart JW. Pyrimethamine in the myeloproliferative disorders: a forgotten treatment? Clin Lab Haematol. 1987;9:129-36.

21. Whitehead S. Agranulocytosis associated with maloprim. Br Med J (Clin Res Ed). 1983;286:1515.

22. Winstanley P. Malaria: treatment. J R Coll Physicians Lond. 1998;32:203-7.

23. Lazar HP, Murphy RL, Phair JP. Fansidar and hepatic granulomas. Ann Intern Med. 1985;102:722.

24. Davidson AC, Bateman C, Shovlin C, Marrinan M, Burton GH, Cameron IR. Pulmonary toxicity of malaria prophylaxis. BMJ. 1988;297:1240-1.

25. Svanbom M, Rombo L, Gustafsson L. Unusual pulmonary reaction during short term prophylaxis with pyrimethamine-sulfadoxine (Fansidar). Br Med J (Clin Res Ed). 1984;288:1876.

26. McCormack D, Morgan WK. Fansidar hypersensitivity pneumonitis. Br J Dis Chest. 1987;81:194-6.

27. Pang JA. Non-cardiogenic pulmonary oedema associated with pyrimethamine. Respir Med. 1989;83:247-8.

28. Fish DR, Espir ML. Convulsions associated with prophylactic antimalarial drugs: implications for people with epilepsy. BMJ. 1988;297:526-7.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.