Generic Name: Trimethoprim

  • What is Trimethoprim?

    Trimethoprim is an antibiotic used to treat certain bacterial infections of the urinary tract.

  • What is the most important information I should know about Trimethoprim?

    Trimethoprim can cause serious blood disorders. Tell your doctor if you develop sore throat, fever, pale skin, or discoloration of your skin.

    Use trimethoprim as prescribed by your doctor for the full course of treatment, even if symptoms improve earlier. Do not skip doses. Skipping doses or not completing the full course of trimethoprim can decrease its effectiveness and can lead to the growth of bacteria that are resistant to the effects of trimethoprim.

  • Who should not take Trimethoprim?

    Do not take trimethoprim if you are allergic to it or any of its ingredients, or if you have anemia due to folate deficiency.

  • What should I tell my doctor before I take the first dose of Trimethoprim?

    Tell your doctor about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with trimethoprim. Also, talk to your doctor about your complete medical history, especially if you have kidney or liver disease, have anemia, have vitamin B deficiency, are pregnant, plan to become pregnant, or are breastfeeding.

  • What is the usual dosage?

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

    Adults and children ≥12 years: The recommended dose is 100 milligrams (mg) every 12 hours or 200 mg (two-100 mg tablets) every 24 hours for 10 days.

    If you have kidney impairment, your doctor will adjust your dose appropriately.

  • How should I take Trimethoprim?

    Take trimethoprim exactly as prescribed by your doctor.

  • What should I avoid while taking Trimethoprim?

    Do not miss any of the scheduled doses of trimethoprim.

  • What are possible food and drug interactions associated with Trimethoprim?

    If trimethoprim is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining trimethoprim with phenytoin.

  • What are the possible side effects of Trimethoprim?

    Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking this drug.

    Side effects may include: allergic reactions, blood disorders, fever, itching, nausea, rash, stomach discomfort, swelling of your tongue, vomiting

  • Can I receive Trimethoprim if I am pregnant or breastfeeding?

    The effects of trimethoprim during pregnancy are unknown. Trimethoprim can be found in your breast milk if you take it during breastfeeding. Tell your doctor immediately if you are pregnant, plan to become pregnant, or are breastfeeding.

  • What should I do if I miss a dose of Trimethoprim?

    If you miss a dose of trimethoprim, 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 Trimethoprim?

    Store at room temperature in a dry place.