- What is pyrimethamine? What is its mechanism of action?
- What is pyrimethamine used for?
- What are the side effects of pyrimethamine?
- What is the dosage for pyrimethamine?
- Which drugs or supplements interact (contraindications) with pyrimethamine?
- Is pyrimethamine safe to take if you are pregnant or breastfeeding?
- What else should you know about pyrimethamine?
What is pyrimethamine? What is its mechanism of action?
Pyrimethamine prevents parasites from producing important proteins by blocking the use of folic acid which is necessary for the production of proteins. Preventing parasites from producing important proteins prevents growth and development of new parasites. The FDA approved pyrimethamine in January 1953.
What brand names are available for pyrimethamine?
The brand name for pyrimethamine is Daraprim.
Is pyrimethamine available as a generic drug?
No. Pyrimethamine is not available in generic form.
Do I need a prescription for pyrimethamine?
Yes. You need a prescription from a health-care-provider to obtain pyrimethamine.
What is pyrimethamine used for?
Pyrimethamine is an oral antiparasitic drug used for treating Toxoplasma gondii and plasmodia infections. Toxoplasma gondii is a parasite that causes toxoplasmosis, and plasmodia parasites cause malaria.
What are the side effects of pyrimethamine?
Side effects of pyrimethamine include:
- Severe allergic reactions
- Increased blood levels of phenylalanine
- Weight loss
- Vomiting
- Anemia
- Reduced number of white blood cells
- Reduced number of platelets
- Swelling of the tongue
- Blood in the urine
- Abnormal heart rhythms
What is the dosage for pyrimethamine?
- Toxoplasmosis treatment For the treatment of toxoplasmosis the recommended adult starting dose is 50 to 75 mg of daily with 1 to 4 g daily of a sulfonamide for 1 to 3 weeks depending on the response of the patient and tolerance to therapy. The dosage of each drug should be reduced by half then continued for an additional 4 to 5 weeks.
- Acute malaria treatment For treatment of acute malaria the dose is 25 to 50 mg daily for 2 days with a sulfonamide though chloroquine or quinine are preferred for treatment of acute malaria.
- Malaria prevention For preventing malaria the recommended dose for adults and children over 10 years of age is 25 mg once weekly, and for children 4 through 10 years of age the dose is 12.5 mg (1/2 tablet) once weekly. Infants and children under 4 years of age should receive 6.25 mg (1/4 tablet) once weekly.

QUESTION
Bowel regularity means a bowel movement every day. See AnswerWhich drugs or supplements interact (contraindications) with pyrimethamine?
Combining pyrimethamine with other drugs that block folic acid or drugs that suppress the bone marrow may increase the risk of bone marrow suppression. Examples include sulfonamides or trimethoprim-sulfamethoxazole combinations, proguanil, zidovudine (Retrovir), or methotrexate (Trexall). If signs of folate deficiency develop, pyrimethamine should be discontinued and folinic acid (leucovorin) should be administered until normal bone marrow function is restored.
Is pyrimethamine safe to take if you are pregnant or breastfeeding?
- There are no adequate studies of pyrimethamine in pregnant women. Pyrimethamine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Folic acid should also be given if it is used for the treatment of toxoplasmosis during pregnancy.
- Pyrimethamine is secreted in breast milk. Women should not nurse while taking pyrimethamine.
Summary
Pyrimethamine (Daraprim) is a drug prescribed to treat Toxoplasma gondii (toxoplasmosis) and plasmodia (malaria) infections. Side effects, drug interactions, dosage, storage, and pregnancy and breastfeeding information should be reviewed prior to taking any medication.
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Toxoplasmosis
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Antibiotic Resistance (Drug Resistance, Antimicrobial Resistance)
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Travel Medicine
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Treatment & Diagnosis
Medications & Supplements

Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.