MedicinePOM

Trimethoprim+ Sulfamethoxazole

A combination antibiotic used to treat bacterial infections.

Clinical information

Common uses

infections caused by susceptible bacteria

Common side effects

feeling sick
being sick
loss of appetite
skin rash
hives

Cautions

stop at the first sign of rash — severe skin reactions can occur
may be linked to birth defects if taken in pregnancy
antibiotic-associated diarrhoea (C. difficile) can occur
not for babies under 2 months or severe liver damage

Interactions

warfarin (blood thinner) — bleeding risk, monitor
dofetilide — must not be combined
methotrexate — avoid
phenytoin — levels may rise
diabetes tablets — low blood sugar risk
diuretics and ACE inhibitors — blood and potassium problems

Pregnancy: avoid unless essential — possible birth defect risk

Reference information, not medical advice — always follow your doctor or pharmacist. Source: DailyMed, dailymed.nlm.nih.gov, sulfamethoxazole and trimethoprim label, setid ce44959b-4bfe-4ba9-9fc2-7f9d4663d542 (accessed 2026-08-16)

Approved brands & formulations2

Brand name	Dosage form	Strength	Importer	Category
Trimethoprim+ Sulfamethoxazole	Parenteral ( Injection )	80mg+ 400mg / 5ml	—	POM
Trimethoprim+ Sulfamethoxazole	Parenteral ( Injection )	16mg+ 80mg	—	POM