Trimethoprim/Sulfamethoxazole (By Mouth)

Sulfamethoxazole (sul-fa-meth-OX-a-zole), Trimethoprim (trye-METH-oh-prim)

Treats or prevents infections. This medicine is a "sulfa drug" (sulfonamide).

Brand Name(s):

Septra DS, Bactrim, Septra, Bactrim DS, SMZ-TMP, Sulfatrim, Sulfatrim Pediatric
There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

You should not use this medicine if you have had an allergic reaction to trimethoprim, sulfamethoxazole, or any sulfa drug. Do not use this medicine if you are pregnant or breast feeding, or in some situations if you have severe liver or kidney problems. You should not use this medicine if you have anemia (a problem with your blood) caused by not having enough folic acid in your body. This medicine should not be given to infants under 2 months of age.

How to Use This Medicine:

Tablet, Liquid

• Your doctor will tell you how much of this medicine to use and how often. Do not use more medicine or use it more often than your doctor tells you to.
• Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
• Drink extra fluids so you will pass more urine while you are using this medicine. This will keep your kidneys working well and help prevent kidney problems.
• Keep using this medicine for the full treatment time, even if you feel better after the first few doses. Your infection may not clear up if you stop using the medicine too soon.

If a dose is missed:

• If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use extra medicine to make up for a missed dose.

How to Store and Dispose of This Medicine:

• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Do not freeze the oral liquid.
• Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
• Keep all medicine away from children and never share your medicine with anyone.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Make sure your doctor knows if you are also using a diuretic or "water pill" (such as hydrochlorothiazide, Aldactazide®, Dyazide®, Hyzaar®, Maxzide®, Moduretic®), a blood thinner such as warfarin (Coumadin®), methotrexate (Rheumatrex®, Trexal®), digoxin (Lanoxin®), or indomethacin (Indocin®).
• If you are using medicine to treat depression, kidney transplant, seizures, or diabetes, tell your doctor. Some medicines that treat depression are amitriptyline, nortriptyline, Norpramin®, Vivactil®. Kidney transplants are often treated with cyclosporine (Sandimmune®, Neoral®). Seizures are often treated with phenytoin (Dilantin®). Some medicines that treat diabetes are glipizide, glyburide, metformin, Actos®, Avandia®, Glucotrol®, Glucophage®, Glucovance®. Tell your doctor if you are using any medicine to prevent malaria, such as pyrimethamine (Daraprim®).
• Tell your doctor if you drink alcohol on a regular basis.

Warnings While Using This Medicine:

• Make sure your doctor knows if you have kidney disease, liver disease, G6PD deficiency, porphyria, or thyroid problems. Tell your doctor if you have asthma or severe allergies, especially if you are allergic to any medicines. It is important for your doctor to know if you have HIV or AIDS, because this medicine might work differently.
• Very rarely, this medicine has caused severe side effects. If you start to have a skin rash, or if you think you are having a severe reaction, stop taking this medicine and call your doctor right away. Symptoms of a severe reaction include a sore throat, fever, muscle pain, cough, and trouble breathing. Other symptoms are a skin rash, or the color of your skin turning very pale or yellow, or having purple spots.
• This medicine may make your skin more sensitive to sunlight. Use a sunscreen when you are outdoors. Avoid sunlamps and tanning beds.
• Your doctor might need to check your blood or urine at regular visits while you are using this medicine. Be sure to keep all appointments.
• Make sure any doctor or dentist who treats you knows that you are using this medicine. This medicine may affect the results of certain medical tests.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing.
• Blistering, peeling, red skin rash.
• Confusion, weakness.
• Diarrhea or severe stomach pain, cramps, or bloating.
• Muscle twitching.
• Severe nausea, vomiting, dizziness, or headache.
• Unusual bleeding or bruising.
• Unusual tiredness or weakness.
• Uneven heartbeat, shortness of breath, or numbness or tingling in your hands, feet, or lips.

If you notice these less serious side effects, talk with your doctor:

• Mild nausea, vomiting, loss of appetite.

If you notice other side effects that you think are caused by this medicine, tell your doctor.