Sulfamethoxazole/Trimethoprim
Prescription status is set country by country — the label where you live is the one that applies.
Beta: the medication section is still being tested, and its data may contain errors. Do not rely on it for a decision about your own treatment.
Sulfamethoxazole with trimethoprim is a fixed combination of two antibacterials that block consecutive steps in the bacterial pathway for making folate. Because bacteria must build folate themselves while human cells absorb it from food, the block stops bacterial DNA synthesis. It is used for a range of bacterial infections, including those of the urinary tract, chest and skin.
A usual adult range, not a national label — the dose and the timing differ by country and by product.
Approved uses differ by country — some of these may be off-label or unapproved where you live.
It is taken with food and with plenty of fluid, which eases stomach upset and helps prevent the sulfonamide crystallising in the urine. It makes the skin far more sensitive to sunlight, so strong sun and sunbeds are avoided. It raises the effect of the anticoagulant warfarin and the risk of bleeding, and combined with lisinopril or spironolactone it can push potassium to dangerous levels, so potassium and creatinine are monitored, particularly where kidney function is already reduced. It also interferes with folate, so folate and white cell counts may be followed on longer courses.
See a doctor for any spreading rash, blistering, or peeling of the skin or mouth, as these can signal a severe reaction. Fever, sore throat, unusual bruising or bleeding, muscle weakness, an irregular heartbeat, or a marked drop in urine output also mean prompt medical review.
Reference information, not medical advice. Discuss any change with your doctor.