Pyrimethamine (By mouth)
pir-i-METH-a-meen
Helps prevent malaria and treats toxoplasmosis, an infection caused by a parasite. Is also used to prevent other kinds of infections.
Drug classes
Antimalarial (About this – PubMed Health)
Uses
Uses of This Medicine
Pyrimethamine is an antiprotozoal medicine. Antiprotozoals work by killing protozoa (tiny, one-celled animals) or preventing their growth. Some protozoa are parasites that can cause many different kinds of infections in the body.
This medicine is used with one or more other medicines to treat and prevent malaria and to treat toxoplasmosis. This medicine may also be used for other problems as determined by your doctor.
Pyrimethamine is available only with your doctor’s prescription.
Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, pyrimethamine is used in certain patients with the following medical conditions:
Isosporiasis (treatment and prevention)
Pneumocystis carinii pneumonia (treatment)
For patients taking this medicine for Pneumocystis carinii pneumonia:
Pyrimethamine is used in combination with other medicines for mild to moderate pneumonia in patients who cannot take standard treatment.
Other uses (PubMed Health)
How To Use
Tablet
Your doctor will tell you how much medicine to take and how often. You should not use more of this medicine than your doctor ordered.
You may take this medicine with food if it upsets your stomach or causes vomiting.
This medicine should be taken on a regular schedule. Try not to miss any doses. Keep taking the medicine for as long as your doctor has ordered, even if you feel better.
If a dose is missed:
Take the missed dose as soon as possible, unless it is almost time for your next dose.
Skip the missed dose if it is almost time for your next regular dose.
You should not use two doses at the same time.
How to Store and Dispose of This Medicine:
Store the tablets in a tightly closed container away from heat, direct light, and moisture.
Keep all medicine out of the reach of children. Large doses of this medicine are especially harmful to children.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
Make sure your doctor knows if you are taking phenytoin (Dilantin®), lorazepam (Ativan®), or sulfa drugs such as Bactrim® or Septra®.
When Not To Use
You should not use this medicine if you have had an allergic reaction to pyrimethamine or if you have a severe type of blood disease (megaloblastic anemia) caused by not having enough folic acid in your body.
Warnings
If you are pregnant or breastfeeding, talk to your doctor before taking this medicine. You may need to stop breastfeeding while taking this medicine.
Talk to your doctor before taking this medicine if you have seizures, any blood disorders, kidney disease, liver disease, or a history of alcoholism.
If you develop a skin rash, stop taking this medicine and call your doctor right away.
This medicine may help prevent malaria, but is not used to treat a severe attack of malaria.
Pyrimethamine may cause harmful side effects. To help treat these side effects, you may also be given another medicine called leucovorin. It is important that you take leucovorin exactly as your doctor ordered. Do not skip any doses.
Possible side effects
Summary More details
Call your doctor right away if you notice any of these side effects:
Wheezing or trouble breathing
Swollen tongue
Unexplained fever, sore throat, or chills
Unusual bleeding, bruising, or purple spots on your skin
Yellowing of skin and eyes
Extreme tiredness
Pain when urinating or bloody urine
If you notice these less serious side effects, talk with your doctor:
Headache, dizziness
Nausea or upset stomach
If you notice other side effects that you think are caused by this medicine, tell your doctor.
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
More side effects of this drug
Brand names include
Daraprim
There may be other brand names for this medicine.