Brand Name(s):

  • Bactrim Injection®
  • Septra Injection®

Other Name(s):

  • Sulfamethoxazole and Trimethoprim injection
  • SMX-TMP Injection
  • TMP-SMX Injection

WHY is this medicine prescribed?

Your doctor has ordered sulfamethoxazole and trimethoprim, an antibiotic, to help treat your infection. It will be added to an intravenous fluid that will drip through a needle or catheter placed in your vein for 60-90 or more minutes, two to four times a day.

The combination of sulfamethoxazole and trimethoprim eliminates bacteria that cause many kinds of infections, including pneumonia and urinary tract and intestinal infections. This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Your health care provider (doctor, nurse, or pharmacist) may measure the effectiveness and side effects of your treatment using laboratory tests and physical examinations. It is important to keep all appointments with your doctor and the laboratory. The length of treatment depends on how your infection and symptoms respond to the medication.

What SPECIAL PRECAUTIONS should I follow?

Before administering sulfamethoxazole and trimethoprim,

  • tell your doctor and pharmacist if you are allergic to sulfamethoxazole, trimethoprim, any other sulfa drug, diuretics ('water pills'), oral diabetes medications, or any other drugs.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, particularly anticoagulants ('blood thinners') such as warfarin (Coumadin), cyclosporine (Neoral, Sandimmune), diabetes medications, diuretics ('water pills'), medications for seizures such as phenytoin (Dilantin), methotrexate (Folex, Rheumatrex), and vitamins.
  • tell your doctor if you have a history of alcoholism and if you have or have ever had liver or kidney disease, asthma, severe allergies, anemia, or a glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (an inherited blood disease).
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking sulfamethoxazole and trimethoprim, call your doctor.

HOW should this medicine be used?

Before you administer sulfamethoxazole and trimethoprim, look at the solution closely. It should be clear and free of floating material. Gently squeeze the bag or observe the solution container to make sure there are no leaks. Do not use the solution if it is discolored, if it contains particles, or if the bag or container leaks. Use a new solution, but show the damaged one to your health care provider.

It is important that you use your medication exactly as directed. Do not stop your therapy on your own for any reason because your infection could worsen and result in hospitalization. Do not change your dosing schedule without talking to your health care provider. Your health care provider may tell you to stop your infusion if you have a mechanical problem (such as a blockage in the tubing, needle, or catheter); if you have to stop an infusion, call your health care provider immediately so your therapy can continue.

What SIDE EFFECTS can this medicine cause?

Sulfamethoxazole and trimethoprim may cause side effects. Tell your health care provider if any of these symptoms are severe or do not go away:

  • dizziness or loss of balance
  • loss of appetite
  • upset stomach

If you experience any of the following symptoms, call your health care provider immediately:

  • sore throat
  • difficulty breathing
  • fever
  • headache
  • joint or muscle aches
  • yellowing of the skin or eyes
  • swelling of the lips or tongue
  • swallowing problems
  • skin rash or skin changes
  • tiredness
  • unusual bleeding or bruising
  • weakness
  • paleness
  • cough
  • diarrhea

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

  • Your health care provider will probably teach you how to prepare each dose of sulfamethoxazole and trimethoprim. Since the medication is stable for only a short time after preparation, prepare your daily doses as directed by your health care provider.

Store your medication only as directed. Make sure you understand what you need to store your medication properly.

Keep your supplies in a clean, dry place when you are not using them, and keep all medications and supplies out of reach of children. Your health care provider will tell you how to throw away used needles, syringes, tubing, and containers to avoid accidental injury.

What should I do in case of OVERDOSE?

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

If you are receiving sulfamethoxazole and trimethoprim in your vein or under your skin, you need to know the symptoms of a catheter-related infection (an infection where the needle enters your vein or skin). If you experience any of these effects near your intravenous catheter, tell your health care provider as soon as possible:

  • tenderness
  • warmth
  • irritation
  • drainage
  • redness
  • swelling
  • pain

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Last Reviewed: September 1, 2010.