Antibiotics for Urinary Tract Infections (UTIs)

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Antibiotics for Urinary Tract Infections (UTIs)


Generic NameBrand Name
nitrofurantoin Macrobid
sulfamethoxazole with trimethoprim Septra

How It Works

These medicines kill the bacteria that commonly cause urinary tract infections (UTIs).

Most antibiotics come in pill or liquid form. Some may be given as a shot. The doctor may give this medicine in the vein (intravenously) if you have a severe kidney infection.

Why It Is Used

Antibiotics treat a UTI. And they prevent complications of infection such as kidney damage.

Antibiotics also prevent UTIs. The doctor might prescribe preventive antibiotic therapy for:

  • Women who have recurrent UTIs (at least two UTIs in 6 months or three UTIs in 1 year).
  • Pregnant women who had recurrent UTIs before getting pregnant or during pregnancy.
  • People who have spinal cord injuries or other nervous system conditions that affect urination.
  • People who have had a kidney transplant.
  • People who are going to have surgery involving the urinary tract.

How Well It Works

Antibiotics are effective for most UTIs. With these medicines, you can expect relief of symptoms in 2 to 3 days.1

When taken as preventive therapy, antibiotics also reduce the number of recurrent UTIs. But studies show that this kind of treatment is short-acting. When you stop taking an antibiotic, you are likely to get another UTI.2

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call 911 or other emergency services right away if you have:

  • Trouble breathing.
  • Hives.
  • Swelling of your face, lips, tongue, or throat.

Call your doctor right away if you have signs of an infection that is getting worse, such as:

  • Chills.
  • Fever.
  • Abdominal (belly) pain.
  • Nausea or vomiting.

Ciprofloxacin and levofloxacin

Call your doctor right away if you have:

  • Sudden pain after exercise (especially in your ankle, back of the knee or leg, shoulder, elbow, or wrist).
  • Pain, burning, numbness, tingling, or weakness.
  • Fainting.
  • An irregular or slow heart rate.


Call your doctor right away if you have:

  • A change in skin colour.
  • Chest pain.
  • Joint or muscle pain.

Sulfamethoxazole with trimethoprim

Call your doctor right away if you have:

  • Changes to the skin, such as peeling or blistering.
  • Joint or muscle pain.
  • Unusual bleeding, such as:
    • Blood spots under your skin.
    • A nosebleed that you cannot stop.
    • Bleeding gums when you brush your teeth.

Common side effects of antibiotics include:

  • Diarrhea.
  • Dizziness.
  • Gas.
  • Headache.
  • Tiredness.
  • Mild stomach pain or cramps, nausea, loss of appetite.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Antacids containing magnesium or aluminum and iron or zinc supplements should be taken at least 6 hours before or 2 hours after taking ciprofloxacin or levofloxacin.

Most of these antibiotics can make your skin more sensitive to the sun.

  • Stay out of the sun, if possible.
  • Wear long pants, long-sleeved shirts, and hats, if possible.
  • Use sunscreen with an SPF that your doctor recommends.

If your doctor prescribes antibiotics, ask whether there are any potential drug interactions you should be aware of. For instance, some antibiotics that are used to treat UTIs may make birth control pills less effective. Your doctor may recommend a backup form of birth control. Antibiotics can also change the way the anticoagulant (blood thinner) warfarin (Coumadin) works so that you bleed too easily.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.

Be sure to take all of the medicine your doctor gives you. Do this even if you feel better. If you do not take all of your medicine as prescribed, the infection may return. Not taking the full course of antibiotics also encourages the development of bacteria that are resistant to antibiotics. This makes antibiotics less effective. And it makes bacterial infections harder to treat.

Advice for women

Ciprofloxacin and levofloxacin

Do not use this medicine if you are pregnant, breast-feeding, or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.


If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.

Sulfamethoxazole with trimethoprim

Do not use this medicine if you are pregnant, breast-feeding, or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. Schaeffer AJ (2002). Infections of the urinary tract. In OC Walsh et al., eds., Campbell's Urology, 8th ed., vol. 1, pp. 515–592. Philadelphia: W.B. Saunders.
  2. Sen A (2008). Recurrent cystitis in non-pregnant women, search date April 2007. Online version of BMJ Clinical Evidence:


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Avery L. Seifert, MD - Urology
Last Revised July 12, 2011

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.