Antrim Tablet

Combination antibacterial (co-trimoxazole) for:

• Urinary tract infections
• Pneumocystis jirovecii pneumonia (treatment and prevention, e.g. in HIV)
• Toxoplasmosis (prevention in HIV)
• Acute exacerbation of chronic bronchitis, some ear infections
• Shigellosis and traveller's diarrhoea (where bacteria are sensitive)
• Nocardiasis and some skin infections (including MRSA in selected cases)

Adults: 960 mg (800 mg + 160 mg, "DS" tablet) twice daily; or two 480 mg tablets twice daily. UTI: 3–7 days (14 days in men/complicated).

Pneumocystis pneumonia: 120 mg/kg/day (as combined drug) in 2–4 divided doses for 14–21 days (in hospital).

Prevention in HIV: 960 mg once daily (or three times weekly).

Children (over 6 weeks): about 24 mg/kg (combined) twice daily; e.g. suspension 240 mg/5 ml — 6 weeks–5 months 2.5 ml, 6 months–5 years 5 ml, 6–12 years 10 ml twice daily.

• Take with food and plenty of water.

• Allergy to sulphonamides or trimethoprim
• Severe liver or kidney failure (without monitoring)
• Babies under 6 weeks (except for specific indications), and in late pregnancy near delivery
• Megaloblastic anaemia due to folate deficiency
• Acute porphyria

Common: nausea, vomiting, loss of appetite, rash, itching, high potassium, thrush.

Less common: diarrhoea, headache, sun sensitivity.

Rare but serious: severe skin reactions (Stevens–Johnson syndrome/TEN) — stop at first sign of rash; blood disorders (low white cells, platelets), liver damage, aseptic meningitis, low blood sugar, kidney problems.

• Stop immediately if a rash, sore throat, fever or mouth ulcers appear.
• Drink plenty of fluids to avoid crystals in urine.
• Elderly, folate deficiency, kidney disease, G6PD deficiency, HIV: higher risk of side effects; blood counts and potassium may need checking.
• Avoid strong sunlight.

Avoid in the first trimester (folate antagonist) and near term (risk of jaundice in the newborn) unless essential. Avoid while breastfeeding a premature, jaundiced or G6PD-deficient baby.

• Warfarin (bleeding risk — monitor INR)
• Methotrexate, pyrimethamine (bone-marrow toxicity)
• Phenytoin, digoxin (levels rise)
• ACE inhibitors, ARBs, spironolactone, potassium supplements (high potassium)
• Sulphonylureas (low blood sugar)
• Ciclosporin (kidney toxicity)

Nausea, vomiting, dizziness, confusion; bone-marrow suppression with prolonged overdose. Seek medical care; folinic acid may be used.

Store below 30°C, protected from light.