pyrimethamine

Generic Name: pyrimethamine (PIR i METH a meen)

Brand Names: Daraprim

What is pyrimethamine?

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

Pyrimethamine is used to treat and prevent malaria. Pyrimethamine is also used in the treatment of toxoplasmosis.

Pyrimethamine may also be used for purposes other than those listed in this medication guide.

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

Stop taking pyrimethamine and seek medical attention at the first sign of a skin rash, sore throat, paleness of the skin, unusual bruising under the skin, or swelling of the tongue. These may be early symptoms of serious side effects of pyrimethamine. Pyrimethamine may cause stomach upset or vomiting. Take each dose with food to lessen this side effect.

What should I discuss with my healthcare provider before taking pyrimethamine?

Before taking pyrimethamine, tell your doctor if you have

• 
  

  had an allergic reaction to previous treatment with pyrimethamine,

  
  


• 
  

  megaloblastic anemia due to folate deficiency,

  
  


• 
  

  seizures or epilepsy,

  
  


• kidney disease, or


• liver disease.

You may not be able to take pyrimethamine, or you may require a dosage adjustment or special monitoring during treatment if you have any of the conditions listed above.

Pyrimethamine is in the FDA pregnancy category C. This means that it is not known whether pyrimethamine will be harmful to an unborn baby. Do not take pyrimethamine without first talking to your doctor if you are pregnant or could become pregnant during treatment. Pyrimethamine passes into breast milk and may be harmful to a nursing infant. Do not take pyrimethamine without first talking to your doctor if you are breast-feeding a baby.

How should I take pyrimethamine?

Take pyrimethamine exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water. Take pyrimethamine with food to lessen stomach upset. Store pyrimethamine at room temperature away from moisture and heat.

See also: Pyrimethamine dosage (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and only take the next regularly scheduled dose. Do not take a double dose of the medication.

What happens if I overdose?

Seek emergency medical attention.

Symptoms of a pyrimethamine overdose may include abdominal pain, nausea, severe vomiting (possibly with blood in the vomit), anxiety or excitability, and seizures.

What should I avoid while taking pyrimethamine?

There are no restrictions on foods, beverages, or activities during treatment with pyrimethamine unless otherwise directed by your doctor.

Pyrimethamine side effects

Stop taking pyrimethamine and seek emergency medical attention if you experience an allergic reaction (swelling of the lips, tongue, or face; difficulty breathing; closing of the throat; or hives) during treatment with pyrimethamine. Stop taking pyrimethamine and seek medical attention at the first sign of a skin rash, sore throat, paleness of the skin, unusual bruising under the skin, or swelling of the tongue. These may be early symptoms of serious side effects of pyrimethamine.

Other, less serious side effects may be more likely to occur. Continue to take pyrimethamine and talk to your doctor if you experience

• 
  

  nausea, vomiting, or loss of appetite;

  
  


• 
  

  insomnia;

  
  


• 
  

  headache;

  
  


• 
  

  lightheadedness; or

  
  


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  dryness of the mouth.

  
  

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Pyrimethamine Dosing Information

Usual Adult Dose for Malaria Prophylaxis:

25 mg orally once a week. Prophylaxis should begin one week prior to departure and continue for at least 6 to 10 weeks following exposure.

Usual Adult Dose for Toxoplasmosis:

Initially: 50 to 75 mg orally once a day with 1 to 4 g of a sulfonamide (e.g., sulfadoxine, sulfadiazine). Continue for 1 to 3 weeks, depending on response and tolerance. Dosage for each drug may then be reduced by one-half and continued for an additional 4 or 5 weeks. Patients receiving pyrimethamine should also receive folinic acid.

Usual Adult Dose for Toxoplasmosis -- Prophylaxis:

1 mg/kg or 15 mg/m2 (max 25 mg) orally every day plus folinic acid (leucovorin) 5 mg orally every 3 days plus sulfadiazine 85 to 120 mg/kg/day divided into 2 to 4 oral doses. Clindamycin 20 to 30 mg/kg/day may be used in place of sulfadiazine as an alternative regimen.

Usual Adult Dose for Pneumocystis Pneumonia Prophylaxis:

50 to 75 mg orally once a week. Pyrimethamine is used in combination with dapsone and leucovorin. This is considered an alternative regimen for patients who do not tolerate trimethoprim-sulfamethoxazole.

Usual Pediatric Dose for Malaria Prophylaxis:

Less than 4 years: 6.25 mg orally once a week.

4 to 10 years: 12.5 mg orally once a week.

Usual Pediatric Dose for Toxoplasmosis:

Newborns and infants:
Initial: 2 mg/kg/day orally divided every 12 hours for 2 days, then 1 mg/kg/day once daily given with sulfadiazine for the first 6 months; next 6 months: 1 mg/kg/day 3 times per week with sulfadiazine; oral folinic acid 5 to 10 mg 3 times per week should be administered to prevent hematological toxicity.

1 to 12 years: 2 mg/kg/day divided every 12 hours for 3 days followed by 1 mg/kg/day (maximum 25 mg/day) once daily or divided twice daily for 4 weeks given with sulfadiazine; oral folinic acid 5 to 10 mg 3 times per week should be administered to prevent hematological toxicity.

What other drugs will affect pyrimethamine?

Before taking pyrimethamine, tell your doctor if you are taking any of the following medicines:

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  auranofin (Ridaura);

  
  


• 
  

  aurothioglucose (Solganal); or

  
  


• 
  

  or gold sodium thiomalate (Aurolate, Myochrysine).

  
  

You may not be able to take pyrimethamine, or you may require a dosage adjustment or special monitoring during treatment.

Drugs other than those listed here may also interact with pyrimethamine. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines, including herbal products.

More pyrimethamine resources

• Pyrimethamine Side Effects (in more detail)
• Pyrimethamine Dosage
• Pyrimethamine Use in Pregnancy & Breastfeeding
• Pyrimethamine Drug Interactions
• Pyrimethamine Support Group
• 0 Reviews for Pyrimethamine - Add your own review/rating

• pyrimethamine Advanced Consumer (Micromedex) - Includes Dosage Information


• Pyrimethamine Professional Patient Advice (Wolters Kluwer)


• Pyrimethamine MedFacts Consumer Leaflet (Wolters Kluwer)


• Daraprim Prescribing Information (FDA)


• Daraprim Monograph (AHFS DI)

Compare pyrimethamine with other medications

• Malaria Prevention
• Pneumocystis Pneumonia Prophylaxis
• Toxoplasmosis
• Toxoplasmosis, Prophylaxis

Where can I get more information?

• Your pharmacist can provide more information about pyrimethamine.

See also: pyrimethamine side effects (in more detail)