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Pyrimethamine and sulfadoxine (Oral)

Generic name: pyrimethamine and sulfadoxine [ pir-i-METH-a-meen, sul-fa-DOX-een ]
Brand name: Fansidar
Drug class: Antimalarial combinations

Medically reviewed by Drugs.com. Last updated on Dec 7, 2023.

Oral route(Tablet)

Fatalities associated with the administration of pyrimethamine/sulfadoxine have occurred due to severe reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis. Pyrimethamine/sulfadoxine prophylaxis must be discontinued at the first appearance of skin rash, if a significant reduction in the count of any formed blood elements is noted, or upon the occurrence of active bacterial or fungal infections .

Uses for pyrimethamine and sulfadoxine

Sulfadoxine , a sulfa medicine, and pyrimethamine combination is used to treat malaria. This medicine may also be used to prevent malaria in people who are living in, or will be traveling to, an area where there is a chance of getting malaria. Sulfadoxine and pyrimethamine combination may also be taken with other medicines for malaria, or may be used for other problems as determined by your doctor.

Since sulfadoxine and pyrimethamine combination may cause some serious side effects, it generally is used only to prevent or treat serious malaria infections in areas where it is known that other medicines may not work.

This medicine is available only with your doctor's prescription.

Before using pyrimethamine and sulfadoxine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Sulfadoxine and pyrimethamine combination should not be used in infants up to 2 months of age.

Geriatric

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of sulfadoxine and pyrimethamine combination in the elderly with use in other age groups.

Breast Feeding

Studies in women breastfeeding have demonstrated harmful infant effects. An alternative to this medication should be prescribed or you should stop breastfeeding while using this medicine.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of pyrimethamine and sulfadoxine

Do not give this medicine to infants younger than 2 months of age unless otherwise directed by your doctor. Also, keep this medicine out of the reach of children. Overdose is especially dangerous in children.

Sulfa-containing medicines are best taken with a full glass (8 ounces) of water. Several additional glasses of water should be taken every day, unless otherwise directed by your doctor. Drinking extra water will help to prevent some unwanted effects (e.g., kidney stones) of this medicine. If this medicine upsets your stomach or causes vomiting, it may be taken with meals or a snack.

For patients taking this medicine to prevent malaria :

For patients taking this medicine to treat malaria :

For patients taking this medicine to self-treat presumed malaria:

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Precautions while using pyrimethamine and sulfadoxine

If this medicine causes skin rash, itching, redness, sores in the mouth or on the genitals (sex organs), or sore throat, check with your doctor immediately. These may be early warning signs of more serious skin or related problems that could develop later.

Malaria is spread by mosquitoes. If you are living in, or will be traveling to, an area where there is a chance of getting malaria, the following mosquito-control measures will help to prevent infection:

For patients taking this medicine to prevent malaria :

If you have a severe reaction from the sun, check with your doctor.

For patients taking this medicine to self-treat presumed malaria:

Side Effects of pyrimethamine and sulfadoxine

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Less common

Rare

Symptoms of overdose

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Commonly used brand name(s)

In the U.S.

Pharmacologic Class: Folic Acid Antagonist

Chemical Class: Sulfonamide

More about pyrimethamine / sulfadoxine

Patient resources

Other brands

Fansidar

Professional resources

Other brands

Fansidar

Related treatment guides

Further information

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