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pyrimethamine and sulfadoxine

Generic Name: pyrimethamine and sulfadoxine (PIR i METH a meen and SUL fa DOX een)
Brand Name: Fansidar

What is pyrimethamine and sulfadoxine?

Pyrimethamine is an antiparasitic drug. It prevents the growth and reproduction of parasites.

Sulfadoxine is a sulfa drug that fights bacteria in the body.

The combination of pyrimethamine and sulfadoxine is used to treat malaria, a disease caused by parasites. Parasites that cause malaria typically enter the body through the bite of a mosquito. Malaria is common in areas such as Africa, South America, and Southern Asia.

Pyrimethamine and sulfadoxine is usually given when other anti-malaria medications may not be as effective in treatment or prevention.

Pyrimethamine and sulfadoxine may also be used for purposes not listed in this medication guide.

What is the most important information I should know about pyrimethamine and sulfadoxine?

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.

What should I discuss with my health care provider before taking pyrimethamine and sulfadoxine?

You should not use this medication if you are allergic to pyrimethamine, sulfadoxine, or other sulfa drugs, or if you have certain conditions. Be sure your doctor knows if you have:

  • liver or kidney disease (if using the medication long-term);

  • a blood cell disorder (such as anemia);

  • anemia caused by a folic acid deficiency;

  • if you are in late pregnancy; or

  • if you are breast-feeding.

Before using pyrimethamine and sulfadoxine, tell your doctor if you are allergic to any drugs, or if you have:

  • liver or kidney disease; or

  • glucose-6-phosphate dehydrogenase (G6PD) deficiency.

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.

Malaria is more likely to cause death in a pregnant woman. If you are pregnant, talk with your doctor about the risks of traveling to areas where malaria is common.

Do not use this medication if you are breast-feeding a baby.

Do not give this medication to a child without a doctor's advice. Babies younger than 2 months old should not receive pyrimethamine and sulfadoxine.

How should I take pyrimethamine and sulfadoxine?

Take this medication exactly as prescribed by your doctor. Do not take it in larger amounts or for longer than recommended. Follow the directions on your prescription label.

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.

To treat malaria, this medication is usually given as a single dose of 1/2 to 3 tablets. Follow your doctor's instructions.

If you are taking this medicine to prevent malaria, start taking it 1 or 2 days before entering an area where malaria is common. Take the medication every day during your stay and for 4 to 6 weeks after you leave.

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.

If you take this medication for longer than 3 months, your blood may need to be tested on a regular basis. Do not miss any scheduled appointments.

Contact your doctor as soon as possible if you have been exposed to malaria, or if you have fever or other symptoms of illness during or after a stay in an area where malaria is common.

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.

Store pyrimethamine and sulfadoxine at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include nausea, vomiting, loss of appetite, fever, chills, sore throat, swollen tongue, or seizure (convulsions).

What should I avoid while taking pyrimethamine and sulfadoxine?

Avoid exposure to sunlight or artificial UV rays (sunlamps or tanning beds) while taking this medication.

Pyrimethamine and sulfadoxine side effects

Get emergency medical help if you have any of these signs of an allergic reaction: 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:

  • the first sign of any skin rash, no matter how mild;

  • a severe blistering, peeling, and red skin rash;

  • pale skin, easy bruising or bleeding;

  • feeling tired, weak, or dizzy;

  • hallucinations, seizure (convulsions);

  • urinating less than usual or not at all;

  • jaundice (yellowing of the skin or eyes); or

  • fever, chills, sore throat, swollen tongue, joint pain, cough, feeling short of breath.

Less serious side effects may include:

  • mild stomach pain, feeling full;

  • slight hair loss;

  • headache;

  • muscle weakness;

  • depression, nervousness;

  • ringing in your ears; or

  • sleep problems (insomnia).

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Pyrimethamine and sulfadoxine dosing information

Usual Adult Dose for Malaria:

2 or 3 tablets taken orally as a single dose, following a 3 to 7 day course of quinine (650 mg every 8 hours).

Usual Adult Dose for Malaria Prophylaxis:

1 tablet orally every week beginning 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

Alternative: 2 tablets every 2 weeks beginning 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

Usual Adult Dose for Pneumocystis Pneumonia Prophylaxis:

1 tablet (25/500 mg) orally once or twice a week.

Pyrimethamine-sulfadoxine is generally not recommended for PCP prophylaxis unless trimethoprim-sulfamethoxazole, pentamidine, dapsone/pyrimethamine/leucovorin, atovaquone, or dapsone cannot be used.

Usual Pediatric Dose for Malaria:

>2 months:
5-10 kg: One-half tablet orally one time
11-20 kg: 1 tablet orally one time
21-30 kg: 1.5 tablet orally one time
31-45 kg: 2 tablets orally one time
>45 kg: 3 tablets orally one time

A 3 to 7-day course of quinine should precede the pyrimethamine-sulfadoxine dose.

Usual Pediatric Dose for Malaria Prophylaxis:

> 2 months:
5-10 kg: 1/4 (0.25) tablet orally once a week
11-20 kg: 1/2 (0.5) tablet orally once a week
21-30 kg: 3/4 (0.75) tablet orally once a week
31-45 kg: 1 tablet orally once a week
>45 kg: 1.5 tablet orally once a week

Begin 1 or 2 days before departure to an endemic area; continue administration during the stay and for 4 to 6 weeks after returning.

What other drugs will affect pyrimethamine and sulfadoxine?

Tell your doctor about any other anti-malaria medications you are taking.

The following drugs can interact with pyrimethamine and sulfadoxine. Tell your doctor if you are using any of these:

  • chloroquine (Aralen); or

  • sulfa drugs (Bactrim, Gantanol, Septra, and others);

This list is not complete and there may be other drugs that can interact with pyrimethamine and sulfadoxine. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

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

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