About trimethoprim bp sulphamethoxazole bp
Sulfonamide-antibiotic combination
Used for
- Urinary tract infections
- Certain ear infections
- Pneumocystis pneumonia treatment or prevention
- Some gastrointestinal bacterial infections
Usual adult dose
For many infections, 960 mg trimethoprim/sulfamethoxazole twice daily; dose and duration vary by infection and kidney function.
Usual dose in children
For many infections, 4 mg/kg trimethoprim plus 20 mg/kg sulfamethoxazole every 12 hours; specialist dosing varies by condition.
Common side effects
- Nausea, vomiting, or reduced appetite
- Skin rash and itching
- Diarrhea
- Increased sensitivity to sunlight
Important warnings
- Rarely causes severe skin reactions or blood disorders; seek urgent assessment for concerning symptoms.
- Avoid with sulfonamide allergy or severe liver or kidney disease without specialist guidance.
- May raise potassium or affect blood counts; monitoring may be needed.
- Use only for infections it treats; resistance makes it ineffective for some illnesses.
Pregnancy
May affect folate metabolism and newborn bilirubin; use during pregnancy only when a clinician considers it necessary.
Breastfeeding
Small amounts enter breast milk; avoid or seek specialist guidance with premature, jaundiced, ill, or G6PD-deficient infants.
Interactions
- Warfarin: may increase bleeding risk.
- Methotrexate: may increase toxicity.
- ACE inhibitors or spironolactone: may increase potassium.
- Phenytoin: may increase phenytoin levels.
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 It may be incomplete or out of date.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.