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Sulfamethoxazole / Trimethoprim

Antibiotic

Brand names:

Bactrim®, Septra®, Sulfatrim®

Other names:

SMX-TMP, Co-trimoxazole

Often used for:

Infections

About Sulfamethoxazole / Trimethoprim

Sulfamethoxazole/Trimethoprim is an antibiotic. It works to kill bacteria that cause infections. Some patients may receive this medicine to prevent pneumonia during chemotherapy. This medicine may also be given to treat infections. Follow dosing instructions carefully.

Patients may have tests to monitor blood counts while receiving this medicine.

May be taken as a tablet by mouth

May be taken as a liquid by mouth

May be given as a liquid into a vein by IV

Possible Side Effects

Nausea and vomiting
Rash
Sun sensitivity
Loss of appetite
Diarrhea
Abdominal pain
Low blood counts

Not all patients who take sulfamethoxazole/trimethoprim will experience these side effects. Common side effects are in bold, but there may be others. Please report all suspected side effects to your doctor or pharmacist.

Tips for Families

Be sure to discuss these and other recommendations with your doctor or pharmacist.

While taking this medicine, it is important to drink plenty of fluids. Patients should follow the care team’s instructions for appropriate fluid intake.
This medicine may affect some lab tests.
Patients should avoid drinking alcohol while on this medicine.
Patients should protect their skin from the sun while taking this medicine.
Patients should tell their doctor if they are pregnant, trying to get pregnant, or breastfeeding.
Finish all doses of the medicine as instructed by a doctor or pharmacist.

Sulfamethoxazole/Trimethoprim at home:

Take medicine at the same time each day.
This medicine can be taken with or without food. Take with food if stomach upset occurs.
Take medicine with a full glass of water.
Liquid medicine: Shake well, and use the measuring device that comes with the medicine.
Store at room temperature. Protect from light.
Give a missed dose as soon as possible. If it is near the time of the next dose, skip the dose. Do not give 2 doses at the same time.
Do not use the medicine past the expiration date.
Follow instructions for safe storage and disposal.

Learn More About Sulfamethoxazole/Trimethoprim

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Always check the medication label. Many medicines look the same. Do not take any new medicine, including over-the-counter medicines or supplements, without checking with your doctor or pharmacist. Talk to your doctor or pharmacist about what to do in the case of a missed dose, allergic reaction, or medical emergency. This information is not intended to be a complete guide and is not a substitute for talking with your provider. Medicine names, appearance, formulas, or availability may vary by clinic location. Always follow the instructions given by your care team.