Generic Name: Sulfamethoxazole

  • What is this medication and its most common uses?

    Bactrim is an antibiotic used to treat certain bacterial infections, including urinary tract infections, ear infections, enteritis (inflammation of the small intestine), pneumonia, traveler's diarrhea, and episodes of difficulty breathing in people with chronic (long-term) bronchitis. Bactrim is also used to prevent pneumonia in people with a weakened immune system. Bactrim contains two medicines: sulfamethoxazole and trimethoprim. Bactrim is available as Bactrim tablets and Bactrim DS (double strength) tablets.

  • What should I know when beginning and continuing on this medication?

    How does this medication work?

    Bactrim works by stopping the growth of bacteria, thereby treating your infection.

    Bactrim does not treat viral infections, such as the common cold.

    What are the beneficial effects of this medication and when should I begin to have results?

    What: Bactrim may help to treat your infection, thereby improving your symptoms.

    When: Everyone responds differently to treatment, so try to be patient and follow your healthcare provider's directions. It is important that you take Bactrim exactly as your healthcare provider has prescribed for the full course of treatment, even if your symptoms improve earlier.

    How do I know it is working?

    You may start to notice an improvement in your symptoms. This is a good indicator that your medication is working. Your healthcare provider may ask you questions and order tests to assess how well your infection is being treated.

  • What are the possible side effects of this medication?

    The following is not a full list of side effects. Side effects cannot be anticipated. If any develop or change in intensity, tell your healthcare provider as soon as possible. Only your healthcare provider can determine if it is safe for you to continue taking this medication.

    More common side effects may include: nausea, vomiting, decreased appetite, rash, hives.

    Less common side effects may include:

    Serious allergic reactions, with symptoms such as skin rash, sore throat, fever, joint pain, cough, shortness of breath, paleness, or yellowing of your skin or the whites of your eyes.

    Low platelet (type of blood cells that form clots to help stop bleeding) levels that may be life-threatening, but usually go back to normal within a week of stopping treatment with Bactrim.

    Watery and bloody stools (with or without stomach cramps and fever), even as late as two or more months after having taken the last dose of Bactrim.

    Bactrim can harm your unborn baby. Talk to your healthcare provider about other treatment options if you plan to become pregnant. Tell your healthcare provider right away if you become pregnant while taking Bactrim.

  • Who should not take this medication?

    Do not take Bactrim if you are allergic to it or any of its ingredients.

    Do not take Bactrim if you have a history of low platelet levels with previous treatment with Bactrim or either of its ingredients.

    Do not take Bactrim if you have a certain type of anemia (low red blood cell counts), or liver or kidney problems.

    Do not give Bactrim to children <2 months of age.

  • What should I tell my healthcare provider before I take the first dose of this medication?

    Tell your healthcare provider about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with Bactrim. Also, talk to your healthcare provider about your complete medical history, especially if you have asthma; kidney, liver, or thyroid problems; porphyria (a blood disorder); malabsorption syndrome (your small intestine cannot absorb nutrients from food); acquired immunodeficiency syndrome (AIDS); glucose-6-phosphate dehydrogenase (G6PD) deficiency (lack of an enzyme responsible for the breakdown of red blood cells); frequently drink excessive amounts of alcohol; take seizure medicines; or if you are pregnant, plan to become pregnant, or are breastfeeding.

  • What is the usual dosage?

    The information below is based on the dosage guidelines your healthcare provider uses. Depending on your condition and medical history, your healthcare provider may prescribe a different regimen. Do not change the dosage or stop taking your medication without your healthcare provider's approval.

    Urinary Tract Infections

    Adults: The usual dose is 1 Bactrim DS tablet every 12 hours for 10-14 days or 2 Bactrim tablets every 12 hours for 10-14 days.

    If you have kidney impairment, your healthcare provider may adjust your dose appropriately.

    Enteritis and Traveler's Diarrhea

    Adults: The usual dose is 1 Bactrim DS tablet every 12 hours for 5 days or 2 Bactrim tablets every 12 hours for 5 days.

    Episodes of Difficulty Breathing with Chronic Bronchitis

    Adults: The usual dose is 1 Bactrim DS tablet every 12 hours for 14 days or 2 Bactrim tablets every 12 hours for 14 days.

    Treatment of Pneumonia

    Adults and children ≥2 months: Your healthcare provider will prescribe the appropriate dose for you or your child, based on the weight.

    Prevention of Pneumonia

    Adults: The recommended dose is 1 Bactrim DS tablet once a day.

    Urinary Tract Infections, Enteritis, and Ear Infections

    Children ≥2 months: Your healthcare provider will prescribe the appropriate dose for your child, based on his/her weight.

  • How should I take this medication?

    Take Bactrim exactly as prescribed by your healthcare provider. Do not change your dose or stop taking Bactrim without first talking to your healthcare provider.

    Drink plenty of fluids while you are taking Bactrim.

  • What should I avoid while taking this medication?

    Do not skip doses. Skipping doses or not completing the full course of Bactrim can decrease its effectiveness and can lead to the growth of bacteria that are resistant to the effects of Bactrim.

  • What are the possible food and drug interactions associated with this medication?

    If Bactrim is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your healthcare provider before combining Bactrim with the following: amantadine, blood pressure/heart medications known as angiotensin-converting enzyme (ACE) inhibitors (such as lisinopril or enalapril), certain antidepressants (such as amitriptyline or doxepin), certain diabetes medicines (such as glipizide, metformin, or pioglitazone), cyclosporine, digoxin, indomethacin, methotrexate, phenytoin, pyrimethamine, warfarin, or water pills (such as furosemide or hydrochlorothiazide).

  • May I receive this medication if I am pregnant or breastfeeding?

    Bactrim can harm your unborn baby if you take it during pregnancy. Bactrim can be found in your breast milk if you take it while breastfeeding. Tell your healthcare provider immediately if you are pregnant, plan to become pregnant, or are breastfeeding.

  • What should I do if I miss a dose of this medication?

    If you miss a dose of Bactrim, take it as soon as you remember. However, if it is almost time for your next dose, skip the one you missed and return to your regular dosing schedule. Do not take two doses at once.

  • How should I store this medication?

    Store at room temperature.

Meet the Pharmacists

I'm Shereen A. Gharbia, PharmD. Welcome to PDR Health!

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