MedicinePOMEssential

Sulfamethoxazole + Trimethoprim

A combination antibiotic tablet for infections caused by susceptible bacteria.

Clinical information

Common uses

bacterial infections proven or suspected to be susceptible

Common side effects

feeling sick, vomiting, loss of appetite
skin rash
hives (urticaria)

Cautions

rare but severe skin reactions, e.g. Stevens-Johnson syndrome
serious blood disorders can occur
can raise potassium and lower sodium
not for babies under 2 months or severe liver/kidney disease

Interactions

dofetilide — must not be combined
warfarin (blood thinner) — effect increased
phenytoin (seizure medicine)
methotrexate
thiazide diuretics — low platelets in elderly people
ACE inhibitors and similar — high potassium risk

Pregnancy: avoid if possible — may be linked to birth defects

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

Approved brands & formulations5

Brand name	Dosage form	Strength	Importer	Category
Sulfamethoxazole + Trimethoprim	Tablet	400 mg + 80 mg	—	POM
Sulfamethoxazole + Trimethoprim	Tablet	100 mg + 20 mg	—	POM
Sulfamethoxazole + Trimethoprim	Oral Liquid	200 mg + 40 mg/5 ml	—	POM
Sulphamethoxazole + Trimethoprim	Tablet	800mg+160mg	—	POM
Sulphamethoxazole+Trimethoprim	Oral liquid ( Syrup )	400 +80 mg	—	POM