PYRIMETHAMINE oral

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Prescription under medical supervision


Therapeutic action

  • Antiprotozoal

Indications

  • Treatment and secondary prophylaxis of toxoplasmosis in immunodeficient patients, in combination with sulfadiazine or clindamycin
  • Primary prophylaxis of toxoplasmosis in immunodeficient patients, in combination with dapsone (only if co-trimoxazole cannot be used)
  • Second-line treatment of isosporiasis in immunodeficient patients (only if co-trimoxazole cannot be used)

Forms and strengths

  •  25 mg tablet

Dosage and duration

Treatment of toxoplasmosis

  • Adult: 2 doses of 100 mg on D1, then 75 to 100 mg once daily for at least 6 weeks
     

Secondary prophylaxis of toxoplasmosis

  • Adult: 25 to 50 mg once daily, as long as necessary
     

Primary prophylaxis of toxoplasmosis

  • Adult: 50 to 75 mg once weekly, as long as necessary
     

Treatment of isosporiasis

  • Adult: 50 to 75 mg once daily for 10 days

Contra-indications, adverse effects, precautions

  • Do not administer to patients with severe renal or hepatic impairment.
  • May cause: gastrointestinal disturbances, seizures, leucopenia, thrombocytopenia, megaloblastic anaemia due to folic acid deficiency.
  • Administer calcium folinate to prevent folic acid deficiency.
  • Avoid if possible combination with other folate antagonists: co-trimoxazole, methotrexate (increased risk of folic acid deficiency).
  • Monitor combination with zidovudine (increased risk of zidovudine-associated haematotoxicity).
  • Pregnancy: CONTRA-INDICATED during the first trimester
  • Breast-feeding: no contra-indication; however avoid concomitant administration of other folate antagonists.

Remarks

  • The combination of sulfadoxine/pyrimethamine is used for the treatment of uncomplicated falciparum malaria.

Storage

Below 25 °C