About trimethoprim bp sulphamethoxazole bp
Combination antibiotic
Used for
- Serious infections caused by susceptible bacteria
- Pneumocystis pneumonia treatment and prevention
- Certain severe urinary tract infections
Usual adult dose
Intravenous dosing, based on trimethoprim: usually 8–10 mg/kg/day divided every 6–12 hours; Pneumocystis pneumonia: 15–20 mg/kg/day divided every 6–8 hours.
Usual dose in children
From 2 months: intravenous trimethoprim 8–10 mg/kg/day divided every 6–12 hours; Pneumocystis pneumonia: 15–20 mg/kg/day divided every 6–8 hours.
Common side effects
- Nausea, vomiting, or diarrhoea
- Rash and itching
- High potassium levels
- Reduced blood cell counts
Important warnings
- Requires dilution and intravenous infusion; never inject directly.
- Avoid with trimethoprim or sulfonamide allergy.
- Can cause severe skin reactions or blood disorders.
- Kidney impairment requires dose adjustment; blood monitoring may be needed.
Pregnancy
Generally avoided, especially during early pregnancy and near delivery, because of folate interference and potential newborn complications.
Breastfeeding
Usually compatible with breastfeeding healthy, full-term infants after the newborn period; avoided with premature, jaundiced, ill, or G6PD-deficient infants.
Interactions
- Warfarin: increased bleeding risk
- Methotrexate: increased blood and bone marrow toxicity
- Spironolactone, ACE inhibitors, or ARBs: increased potassium
- Phenytoin: increased levels and toxicity
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.