Indications
Sulfadoxine is an antimalarial that is used in a fixed combination with Pyrimethamine. The combination is used to treat uncomplicated falciparum malaria in some settings (often together with Artesunate), and for intermittent preventive treatment of malaria in pregnant women and infants in areas where malaria is common, according to national guidelines. It has also been used to help prevent toxoplasmosis and Pneumocystis infection in people with weak immunity.
How It Works
Sulfadoxine is a long acting sulfonamide. Malaria parasites need folic acid to grow. Sulfadoxine blocks one step in the parasite’s folic acid production, and Pyrimethamine blocks the next step. Together they stop the parasite multiplying. Because Sulfadoxine stays in the body for a long time, a single dose works for many days.
Dosage and Administration
The dose depends on whether it is used for treatment or prevention, and on age or weight. Take it exactly as prescribed by your doctor or as directed by the national malaria programme, usually as a single dose of tablets taken with water after food. Do not repeat doses more often than advised. Children’s doses are based on weight.
Interactions
Do not take with other medicines that block folic acid, such as Co-trimoxazole, Trimethoprim or Methotrexate, as this increases the risk of blood problems. It can increase the effect of Warfarin, Phenytoin and diabetes tablets such as sulfonylureas. Use with Zidovudine or other medicines that lower blood counts needs care.
Contraindications
- Allergy to Sulfadoxine, other sulfonamides (sulfa medicines) or Pyrimethamine.
- History of severe skin reaction to sulfa medicines.
- Severe liver or kidney disease, or blood disorders such as megaloblastic anaemia due to folate deficiency.
- Babies under about 6 to 8 weeks old, because of the risk of jaundice.
- People already taking Co-trimoxazole preventive treatment (for example people with HIV).
Side Effects
Most people have no problems with a single dose. Possible effects include nausea, vomiting, loss of appetite, headache, dizziness, itching or mild rash, and sensitivity to sunlight. Rarely it can affect the blood counts or the liver.
Get urgent medical help if you develop any rash, blisters, peeling skin, mouth or eye sores or fever after taking it, as rare but life threatening skin reactions (Stevens Johnson syndrome) can occur. Also seek help for yellowing of the skin or eyes, sore throat with fever, unusual bleeding or bruising, or severe tiredness and paleness.
Pregnancy and Lactation
Under national programmes it is given as preventive treatment from the second trimester of pregnancy, but not in the first trimester or close to delivery unless advised. Pregnant women taking it are usually advised to take low dose folic acid only, not high dose. It passes into breast milk and should be avoided when breastfeeding very young, premature or jaundiced babies. Follow your doctor’s advice.
Precautions and Warnings
Stop and see a doctor at the first sign of any rash. People with G6PD deficiency, asthma, allergies, liver or kidney problems need extra care. Drink plenty of fluids. Avoid strong sun. Malaria resistance to this combination is common in many areas, so it is not used alone for treatment where resistance exists. Long term use needs regular blood tests.
Overdose
Overdose may cause vomiting, seizures, blood problems and liver damage. Seek emergency medical help at once, especially for a child.
Therapeutic Class
Antimalarial; long acting sulfonamide (used with Pyrimethamine as a folate antagonist combination).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.