Co-trimoxazole (Sulphamethoxazole + Trimethoprim)

Co-trimoxazole (Sulphamethoxazole + Trimethoprim) is a sulfonamide antibiotic combination medicine available in Bangladesh under many brand names. Below are its uses, dosage, side effects and precautions — and all brands with their current prices.

Co-trimoxazole (Sulphamethoxazole + Trimethoprim) is prescribed by doctors for infections caused by susceptible bacteria, including:

• Urinary tract infections (cystitis and some kidney infections)
• Chest and respiratory infections, including certain types of bronchitis
• Pneumocystis pneumonia (PCP) — both treatment and prevention, especially in people with weak immunity
• Certain ear and sinus infections
• Some gastrointestinal infections such as shigellosis and traveller's diarrhoea

The right indication is decided by your doctor after assessing your symptoms and, where needed, laboratory tests.

The dose of Co-trimoxazole (Sulphamethoxazole + Trimethoprim) depends on the infection, its severity, your age and kidney function. The information below is a general guide only.

• Adults: a common course runs for 5 to 14 days, with the tablet usually taken twice daily, morning and evening.
• Children: the dose is calculated by body weight and must be set by a doctor; the syrup form is often used.

Take Co-trimoxazole (Sulphamethoxazole + Trimethoprim) with a full glass of water and drink plenty of fluids during the day. Take your doses at evenly spaced times and finish the whole course your doctor prescribes, even if you feel better earlier.

Most people tolerate Co-trimoxazole (Sulphamethoxazole + Trimethoprim) well, but some side effects can occur:

• Common: nausea, vomiting, loss of appetite and skin rash
• Less common: diarrhoea, sore mouth or tongue, headache
• Serious (seek urgent care): severe or blistering skin rash, peeling skin, high fever, unusual bruising or bleeding, sore throat, marked tiredness or yellowing of the eyes

Co-trimoxazole can rarely cause serious skin and blood reactions. Stop the medicine and contact a doctor immediately if you develop a spreading rash, mouth ulcers or blisters.

Co-trimoxazole (Sulphamethoxazole + Trimethoprim) is a prescription-only antibiotic. Never buy or take it without a registered doctor's advice, and never share it or use leftover medicine for a new illness.

• Complete the full course exactly as prescribed, even if you feel better within a day or two. Stopping early lets the strongest bacteria survive and multiply.
• Antibiotic resistance is a serious and growing crisis in Bangladesh. Misusing antibiotics like co-trimoxazole makes common infections harder — sometimes impossible — to treat in future.
• Tell your doctor if you have ever had a sulfa (sulphonamide) allergy — this medicine can cause severe reactions in such people.
• Drink plenty of water throughout treatment to protect your kidneys.
• Use with caution in the elderly, in kidney problems, and in people with folate deficiency.

Tell your doctor about every medicine, supplement or herbal product you take. Co-trimoxazole (Sulphamethoxazole + Trimethoprim) can interact with:

• Warfarin and other blood thinners — bleeding risk may rise
• Methotrexate — increased toxicity
• Phenytoin (for epilepsy)
• Certain diuretics (water tablets), especially in the elderly
• Drugs that raise potassium, such as ACE inhibitors and spironolactone
• Diabetes tablets (sulphonylureas) — blood sugar may drop

Do not start or stop any medicine during your course without telling the prescriber.

Co-trimoxazole (Sulphamethoxazole + Trimethoprim) should not be used if you have:

• A known allergy to sulphonamides (sulfa drugs) or to trimethoprim
• Severe liver disease or marked kidney failure
• Certain serious blood disorders or severe folate-deficiency anaemia
• Newborn babies (under 6 weeks of age)

It is generally avoided in late pregnancy and breastfeeding. Always tell your doctor your full medical history before starting this medicine.

Co-trimoxazole is generally not recommended during pregnancy, particularly in the first trimester (it affects folic acid) and near delivery. It should only be used if a doctor decides the benefit clearly outweighs the risk.

The drug passes into breast milk, so it is usually avoided while breastfeeding, especially if the baby is premature, jaundiced or unwell. If you are pregnant, planning pregnancy or breastfeeding, tell your doctor before taking Co-trimoxazole (Sulphamethoxazole + Trimethoprim) so a safer option can be chosen if needed.

Store Co-trimoxazole (Sulphamethoxazole + Trimethoprim) in a cool, dry place below 30°C, away from direct sunlight and moisture.

• Keep tablets in their original strip or container.
• Any reconstituted syrup should be kept as advised on the label and used within the stated period.
• Keep this and all medicines out of the reach of children.
• Do not use after the expiry date, and return unused medicine to a pharmacy for safe disposal.