Sulphadiazine + Trimethoprim

Sulphadiazine + Trimethoprim is a potentiated sulfonamide antibacterial medicine available in Bangladesh under many brand names. Below are its uses, dosage, side effects and precautions — and all brands with their current prices.

• Treatment of infections caused by bacteria proven or strongly suspected to be susceptible to Sulphadiazine + Trimethoprim, where the product is licensed for that use.
• May be used for urinary, respiratory, gastrointestinal, or skin and soft-tissue bacterial infections only when considered appropriate by a registered prescriber.
• Not effective for viral infections such as common cold, influenza, or dengue.

The dose and duration depend on the exact product strength, indication, age, body weight, kidney function, and whether the product is intended for human or veterinary use. Adult treatment should follow the registered doctor’s prescription and the product label; do not start, stop, or change the dose on your own. Complete the prescribed course unless the prescriber advises otherwise.

• Common: nausea, vomiting, loss of appetite, diarrhoea, headache, dizziness, and mild skin rash.
• Skin sensitivity to sunlight may occur; avoid excessive sun exposure if advised.
• Serious: severe allergic reaction, Stevens-Johnson syndrome or toxic epidermal necrolysis, severe diarrhoea, liver injury, kidney problems, low blood counts, unusual bruising or bleeding, sore throat with fever, and high potassium.
• People with G6PD deficiency may be at increased risk of haemolysis with sulfonamides.

Use caution in people with kidney or liver disease, folate deficiency, blood disorders, asthma or severe allergy history, G6PD deficiency, dehydration, or in older adults. Adequate fluid intake may be advised to reduce the risk of crystalluria, unless fluid restriction is required for another condition. Use antibiotics only for confirmed or strongly suspected bacterial infection to reduce antimicrobial resistance. Use under a registered doctor's or pharmacist's guidance.

• Warfarin and other anticoagulants: increased bleeding risk; INR monitoring may be needed.
• Methotrexate: increased risk of bone-marrow suppression and toxicity.
• Phenytoin: levels and toxicity may increase.
• ACE inhibitors, ARBs, spironolactone, eplerenone, or potassium supplements: increased risk of high potassium.
• Diuretics, especially in older adults: increased risk of blood disorders has been reported with sulfonamide combinations.
• Other medicines that affect kidneys or bone marrow may increase toxicity risk.

• Known allergy to sulfonamides, trimethoprim, or any component of the product.
• Previous severe skin reaction or serious hypersensitivity to a sulfonamide or trimethoprim-containing medicine.
• Severe liver disease or severe kidney impairment when appropriate monitoring or dose adjustment is not possible.
• Megaloblastic anaemia due to folate deficiency.
• Use in very young infants is generally avoided unless specifically directed by a specialist.

Use during pregnancy only if a doctor considers it clearly necessary, because trimethoprim can interfere with folate metabolism and sulfonamides near delivery may pose risks to the newborn. Breastfeeding mothers should use it only on medical advice; extra caution is needed if the baby is premature, jaundiced, ill, or has G6PD deficiency.

Store in a cool, dry place away from direct sunlight and moisture, and keep out of reach of children. Follow the specific label instructions for bolus, injection, powder, or suspension; do not use after expiry or if the product looks damaged, discoloured, or contaminated.