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    Last updated: September 2022


    Prescription under medical supervision


    Therapeutic action

    • Combination of two antibacterials: a sulfonamide (sulfamethoxazole) and a diaminopyrimidine antifolate (trimethoprim)


    • Treatment of cerebral toxoplasmosis, pneumocystosis, isosporiasis, cyclosporiasis and brucellosis
    • Prophylaxis of pneumocystosis, toxoplasmosis and isosporiasis
    • Second-line treatment of pertussis
    • Uncomplicated typhoid fever if the strain is susceptible (recent drug susceptibility test)

    Forms and strengths

    • 400 mg SMX + 80 mg TMP and 800 mg SMX + 160 mg TMP tablets
    • 100 mg SMX + 20 mg TMP dispersible tablet for paediatric use


    Treatment of cerebral toxoplasmosis

    • Child 1 month and over and adult: 25 mg SMX + 5 mg TMP/kg 2 times daily


    Treatment of pneumocystosis

    • Child 1 month and over: 50 mg SMX + 10 mg TMP/kg (max. 1600 mg SMX + 320 mg TMP) 2 times daily
    • Adult: 1600 mg SMX + 320 mg TMP 3 times daily


    Treatment of isosporiasis and cyclosporiasis 

    • Adult: 800 mg SMX + 160 mg TMP 2 times daily


    Prophylaxis of pneumocystosis, toxoplasmosis and isosporiasis

    • Child 1 month and over: 50 mg SMX + 10 mg TMP/kg (max. 800 mg SMX + 160 mg TMP) once daily, as long as necessary
    • Adult: 800 mg SMX + 160 mg TMP once daily, as long as necessary


    Treament of pertussis, brucellosis and typhoid fever

    • Child 1 month and over: 20 mg SMX + 4 mg TMP/kg (max. 800 mg SMX + 160 mg TMP) 2 times daily
    • Adult: 800 mg SMX + 160 mg TMP 2 times daily


    • Cyclosporiasis: 7 days
    • Isosporiasis: 7 to 10 days
    • Typhoid fever, pertussis: 14 days
    • Pneumocystosis: 21 days
    • Cerebral toxoplasmosis: 4 to 6 weeks
    • Brucellosis: 6 weeks

    Contra-indications, adverse effects, precautions

    • Do not administer to children under 1 month.
    • Do not administer to sulfonamide-allergic patients; patients with severe renal or hepatic impairment.
    • Do not combine with phenytoin (increased plasma concentrations of phenytoin).
    • May cause:
      • gastrointestinal disturbances, hepatic or renal disorders (crystalluria, etc.), metabolic disorders (hyperkalaemia, hypoglycaemia, hyponatraemia); neuropathy, photosensitivity, haemolytic anaemia in patients with G6PD deficiency;
      • allergic reactions (fever, rash, etc.) sometimes severe (Lyell's and Stevens-Johnson syndromes, haematological disorders, etc.); agranulocytosis, megaloblastic anaemia due to folic acid deficiency. In these cases, stop treatment immediately.
    • Adverse effects occur more frequently in patients with HIV infection.
    • In the event of prolonged treatment, monitor blood count if possible.
    • Avoid combination with drugs inducing hyperkalaemia: potassium salts, spironolactone, enalapril, NSAIDs, heparin (increased risk of hyperkalaemia).
    • Monitor combination with: zidovudine (increased haematotoxicity), antidiabetics (increased risk of hypoglycaemia).
    • Drink plenty of water during treatment to reduce risk of crystalluria.
    • Pregnancy: avoid using during the first trimester (risk of malformation) and during the last month of pregnancy (risk of neonatal jaundice and haemolytic anaemia).
    • Breast-feeding: avoid if premature neonate, jaundice, low-birth weight, during the first month of life. If co-trimoxazole is used, observe the child for signs of jaundice.


    • Preferably take during meals.


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