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Care365 medication guide
Trimethoprim-Sulfamethoxazole
Treats selected susceptible infections, including some uncomplicated bladder infections.
Drug information
Uses, directions and safety information for Trimethoprim-Sulfamethoxazole.
What it is used for
Treats selected susceptible infections, including some uncomplicated bladder infections.
How to use it
Dose and duration depend on infection and kidney function; follow the prescription, not another indication’s regimen.
Before use
Avoid relevant sulfonamide/trimethoprim allergy, prior related thrombocytopenia, folate-deficiency anaemia and dofetilide.
Possible side effects
Nausea, diarrhoea and rash.
When to get medical help
Stop and seek care for blistering rash, mouth sores, fever, jaundice or unusual bleeding.
Medicines and interactions
Important interactions include warfarin, methotrexate and potassium-raising medicines.
Pregnancy and breastfeeding
The source contraindicates pregnancy and nursing; infant use has strict age restrictions.
Missed doses, storage and accidental exposure
Follow your own product’s missed-dose instructions. If you are unsure, ask a pharmacist before taking an extra dose. Contraceptives, injections and modified-release medicines may need a specific plan.
Keep the original packaging and follow its storage, expiry and disposal instructions. Keep medicines away from children and pets. Ask about refrigeration, after-opening limits and safe sharps disposal when relevant.
For suspected overdose or accidental swallowing, contact poison control or urgent medical care promptly. Call emergency services for breathing difficulty, collapse or a seizure.
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Related condition guides
Learn about concerns where this medication may be discussed. Treatment depends on your individual assessment.
Prescription renewal and medication review
For a review of Trimethoprim-Sulfamethoxazole, have your current dose, reason for treatment, remaining supply, benefits, side effects and pharmacy details ready. Ask your pharmacist or prescriber whether a renewal assessment is available and appropriate. A prescription or renewal is not guaranteed.
Questions about Trimethoprim-Sulfamethoxazole
What is Trimethoprim-Sulfamethoxazole used for?
Treats selected susceptible infections, including some uncomplicated bladder infections.
How should I use Trimethoprim-Sulfamethoxazole?
Dose and duration depend on infection and kidney function; follow the prescription, not another indication’s regimen.
What side effects can Trimethoprim-Sulfamethoxazole cause?
Nausea, diarrhoea and rash.
When should I get medical help while using Trimethoprim-Sulfamethoxazole?
Stop and seek care for blistering rash, mouth sores, fever, jaundice or unusual bleeding.
Can Trimethoprim-Sulfamethoxazole interact with other medicines?
Important interactions include warfarin, methotrexate and potassium-raising medicines.
What should I know about Trimethoprim-Sulfamethoxazole during pregnancy or breastfeeding?
The source contraindicates pregnancy and nursing; infant use has strict age restrictions.
Sources and product information
Sources checked 2026-09-08. Safety sections are highlights; consult the full product information for complete warnings and instructions.
Check the Canadian Drug Product Database by product name or DIN for current product information.
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