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Septra

Generic name: sulfamethoxazole and trimethoprim (oral) [ SUL-fa-meth-OX-a-zole-and-trye-METH-oh-prim ]
Brand names: Septra, Septra DS
Drug class: Sulfonamides

Medically reviewed by Kaci Durbin, MD. Last updated on Aug 23, 2023.

What is Septra?

Septra contains a combination of sulfamethoxazole and trimethoprim. Sulfamethoxazole and trimethoprim are are both antibiotics that treat different types of infection caused by bacteria.

Septra is used to treat ear infections, urinary tract infections, bronchitis, traveler's diarrhea, shigellosis, and Pneumocystis jiroveci pneumonia.

Warnings

You should not use Septra if you have severe liver disease, kidney disease that is not being monitored, anemia caused by folic acid deficiency, if you take dofetilide, or if you have had low platelets caused by using trimethoprim or a sulfa drug.

You should not take Septra if you are pregnant or breastfeeding.

Before taking this medicine

You should not use Septra if you are allergic to sulfamethoxazole or trimethoprim, or if you have:

Do not use Septra if you are pregnant. This medicine could harm the unborn baby or cause birth defects. Use effective birth control, and tell your doctor if you are pregnant or if you become pregnant.

Do not breastfeed while using this medicine.

This medicine should not be given to a child younger than 2 months old.

To make sure Septra is safe for you, tell your doctor if you have:

How should I use Septra DS?

Take Septra DS exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Drink plenty of fluids to prevent kidney stones while you are using this medicine.

Septra doses are based on weight in children. Use only the recommended dose when giving this medicine to a child.

Use this medicine for the full prescribed length of time, even if your symptoms quickly improve. Skipping doses can increase your risk of infection that is resistant to medication. This medicine will not treat a viral infection such as the flu or a common cold.

You may need frequent medical tests.

This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using Septra.

Store at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include loss of appetite, vomiting, fever, blood in your urine, yellowing of your skin or eyes, confusion, or loss of consciousness.

What should I avoid while using Septra?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor before using anti-diarrhea medicine.

Sulfamethoxazole and trimethoprim could make you sunburn more easily. Avoid sunlight or tanning beds. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Septra side effects

Get emergency medical help if you have signs of an allergic reaction to Septra (hives, cough, chest pain, shortness of breath, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body. Symptoms may include: skin rash, fever, swollen glands, joint pain, muscle aches, severe weakness, pale skin, unusual bruising, or yellowing of your skin or eyes.

Call your doctor at once if you have:

Common Septra side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Septra?

You may need more frequent check- ups or medical tests if you also use medicine to treat depression, diabetes, seizures, or HIV.

Tell your doctor about all your current medicines. Many drugs can affect sulfamethoxazole and trimethoprim, especially:

This list is not complete and many other drugs may affect sulfamethoxazole and trimethoprim. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Popular FAQ

People with a sulfa allergy typically need to avoid sulfonamide antibiotics (antibiotics containing sulfa), including:

  • Septra and Bactrim (sulfamethoxazole-trimethoprim)
  • Pediazole (erythromycin-sulfisoxazole)

Whether other nonantibiotic sulfa-containing drugs need to be avoided with sulfa allergy is unclear and considered on a case-by-case basis. Continue reading

Headache is a common side effect with Bactrim (sulfamethoxazole / trimethoprim) and may occur in up to 10% of patients. Low blood sugar, low sodium blood levels and rarely, aseptic meningitis are other side effects of Bactrim that may lead to a headache. Continue reading

More FAQ

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Septra only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.