CO-TRIMOXAZOLE = SULFAMETHOXAZOLE (SMX)/TRIMETHOPRIM (TMP) oral

Therapeutic action

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

Indications

• 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 

Dosage

Treatment of cerebral toxoplasmosis 

• Child 6 weeks and over and adult: 25 mg SMX/5 mg TMP/kg 2 times daily 

Treatment of pneumocystosis

• Child 4 weeks 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 4 weeks 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

Treatment of pertussis, brucellosis and typhoid fever

• Child 6 weeks 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

Duration

• 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 6 weeks (risk of neonatal hyperbilirubinemia and haemolysis), except for the treatment and prophylaxis of pneumocystosis;
  • to patients with severe renal or hepatic impairment or with history of hypersensitivity to sulfonamides. 
• May cause:
  • haemolytic anaemia in patients with G6PD deficiency, haematologic disorders (thrombocytopenia, leucopenia, agranulocytosis, megaloblastic anaemia due to folic acid deficiency);
  • hypersensitivity reactions (including severe cutaneous reactions such as Stevens-Johnson, Lyell and DRESS syndromes). Early symptoms such as fever, rash, mouth ulcers and bleeding require immediate medical attention. 

In all these cases, stop treatment immediately. 

• gastrointestinal disturbances, hepatic or renal disorders (crystalluria, etc.), metabolic disorders (hyperkalaemia, hypoglycaemia, hyponatraemia);, neuropathy, photosensitivity (protect skin from sun exposure).

• In the event of prolonged treatment, monitor full blood count if possible.
• Avoid or monitor combination with:
  • drugs inducing hyperkalaemia such as potassium salts, spironolactone, enalapril, NSAIDs, heparin (increased risk of hyperkalaemia);
  • phenytoin (increased plasma concentrations of phenytoin);
  • zidovudine (increased risk of haematotoxicity), antidiabetics (increased risk of hypoglycaemia).
• Drink plenty of water during treatment to reduce risk of crystalluria.
• Pregnancy: risk of congenital malformations (first trimester) and neonatal haemolysis and hyperbilirubinaemia (after 36 weeks of pregnancy).
  • For prophylaxis and treatment of pneumocystosis in HIV-exposed and HIV-infected women, the benefits outweigh the risks. If used after 36 weeks of pregnancy, observe the child for signs of anaemia or jaundice.
  • For other indications: avoid if possible.
• Breast-feeding: avoid in women breastfeeding neonates and in women breastfeeding infants that are premature, low birth weight, jaundiced, or ill (same risk as neonates). If used, observe the child for signs of anaemia or jaundice.

Remarks

• Preferably take during meals.

Storage