Where is Pyrimethamine used?

Pyrimethamine is a prescription indicated for the treatment of serious parasite infection of the body, eye, or brain. This is to prevent toxoplasmosis infection in people with HIV infection.

This medication may also be used to treat malaria. Pyrimethamine is an antiparasitic prescription approved by the U.S. Food and Drug Administration (FDA).  This is also a type of drug known as an antiprotozoal. This is mainly used with sulfonamide antibiotics to treat the condition. Pyrimethamine is supplied as tablets for oral administration.

How does Pyrimethamine work?

Pyrimethamine stops the parasite from reproducing once it is in the bloodstream. It does this by blocking the action of a compound that is found in the parasite. This compound is an enzyme called dihydrofolate reductase that is involved in the reproduction of the parasite. Dihydrofolate reductase usually converts folic acid into folinic acid in the parasite. Wherein, it is a step essential for the parasite to produce new genetic material which is the DNA. New DNA is needed for the parasite to reproduce. By blocking its production, Pyrimethamine prevents the parasites from reproducing and increases in number.

In malaria which is caused by various types of parasites known as plasmodium, this drug may also work. Plasmodium is carried by mosquitoes and is injected into the bloodstream during a bite from an infected mosquito. This medication stops malaria parasites from increasing in numbers once in the blood.

Pyrimethamine is well absorbed with peak levels occurring between 2 to 6 hours following administration. It is eliminated slowly and has a plasma half-life of approximately 96 hours.

How is Pyrimethamine taken?

The recommended dosage is based on your medical condition, age, and response to the treatment. Your doctor may direct you to start at a lower dose and eventually increase it. You should take the right dose, not more or less.

Pyrimethamine is to be taken by mouth. This is usually taken once or twice daily or as directed by your doctor. You may take each dose with a meal to lessen nausea and vomiting. Your doctor may lower your dose or direct you to stop taking this drug if vomiting is severe or continues. Swallow the tablet as a whole with a full glass of water. Do not break, chew, or crush it.

What are the possible side effects of Pyrimethamine?

Common side effects:

  • Vomiting
  • Loss of appetite

Stop using Pyrimethamine and call your doctor right away if these occur:

  • Swelling in your tongue
  • Sore throat
  • Easy bruising
  • Blood in your urine
  • Cold or flu symptoms
  • Fever
  • Trouble breathing
  • New or worsening cough

What are the precautions in taking Pyrimethamine?

  • Pyrimethamine can sometimes cause a decrease in the normal amounts of blood cells in the blood. For this reason, you may need to have blood tests every week while having this treatment.
  • This is not recommended for use in the first three months of pregnancy.
  • If you are breastfeeding women, consult your doctor first before using any medicine.
  • Do not share this or any of your medications with others even if they have the same symptoms as yours.