Bactrim (Sulfamethoxazole/ Trimethoprim)







What is Bactrim?

Bactrim contains a combination of sulfamethoxazole and trimethoprim and is supplied in tablets and a liquid suspension. Sulfamethoxazole and trimethoprim are both antibiotics that treat different types of infection caused by bacteria.

Bactrim is used to treat ear infections, urinary tract infections, bronchitis, traveler's diarrhea, and Pneumocystis carinii pneumonia.

Bactrim may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about Bactrim?

You should not use Bactrim if you are allergic to sulfamethoxazole or trimethoprim, if you are pregnant or breast-feeding, or if you have anemia (lack of red blood cells) caused by folic acid deficiency.

Before using Bactrim, tell your doctor if you have kidney or liver disease, a folic acid deficiency, asthma or severe allergies, AIDS, a glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency), or if you are malnourished.

Take this medication for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Bactrim will not treat a viral infection such as the common cold or flu.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

Avoid exposure to sunlight or tanning beds. This medication can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

What should I discuss with my healthcare provider before taking Bactrim?

You should not use Bactrim if you are allergic to sulfamethoxazole or trimethoprim, if you are pregnant or breast-feeding, or if you have anemia (lack of red blood cells) caused by folic acid deficiency.

To make sure you can safely take Bactrim, tell your doctor if you have any of these other conditions:

  • kidney or liver disease;
  • a folic acid deficiency;

  • asthma or severe allergies;

  • AIDS;

  • a glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency); or

  • if you are malnourished.

FDA pregnancy category C. It is not known whether Bactrim will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication. Sulfamethoxazole and trimethoprim can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby. Do not give this medication to a child younger than 2 months old. Older adults may be more likely to have side effects from this medication.

How should I take Bactrim?

Take Bactrim prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Measure liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Take Bactrim for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Bactrim will not treat a viral infection such as the common cold or flu. Drink plenty of fluids to prevent kidney stones while you are taking trimethoprim and sulfamethoxazole. Store the tablets and liquid at room temperature away from moisture, heat, and light.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.




What happens if I overdose?

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

Overdose can cause dizziness, drowsiness, nausea, vomiting, loss of appetite, stomach pain, headache, yellowing of your skin or eyes, blood in your urine, fever, confusion, or fainting.

What should I avoid while taking Bactrim?

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or has blood in it, call your doctor. Do not use any medicine to stop the diarrhea unless your doctor has told you to.

Avoid exposure to sunlight, sunlamps, or tanning beds. Bactrim can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Bactrim side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Call your doctor at once if you have a serious side effect such as:

  • fever, sore throat, and headache with a severe blistering, peeling, and red skin rash;

  • the first sign of any skin rash, no matter how mild;

  • pale skin, easy bruising or bleeding;

  • cough, feeling short of breath;

  • diarrhea that is watery or bloody;

  • feeling restless or irritable, confusion, hallucinations, seizure;

  • slow heart rate, weak pulse, severe tingling, numbness, muscle pain or weakness;

  • nausea, stomach pain, loss of appetite, itching, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

  • fever, chills, body aches, flu symptoms; or

  • urinating less than usual or not at all.

Less serious Bactrim side effects may include:

  • painful or swollen tongue;

  • dizziness, spinning sensation;

  • ringing in your ears;

  • joint pain; or

  • sleep problems (insomnia).

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 Bactrim?

Tell your doctor about all other medications you use, especially:

  • seizure medication such as phenytoin (Dilantin);

  • a diuretic (water pill);

  • a blood thinner such as warfarin (Coumadin);

  • methotrexate (Trexall, Rheumatrex); or

  • an ACE inhibitor such as benazepril (Lotensin), captopril (Capoten), fosinopril (Monopril), enalapril (Vasotec), lisinopril (Prinivil, Zestril), moexipril (Univasc), perindopril (Aceon), quinapril (Accupril), ramipril (Altace), or trandolapril (Mavik).

This list is not complete and there may be other drugs that can interact with Bactrim. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.








Bactrim (Sulfamethoxazole/ Trimethoprim)
Bactrim (Sulfamethoxazole/ Trimethoprim)