Penicillins for urinary tract infections (UTIs)

Examples

Generic Name	Brand Name
amoxicillin	Amoxil
amoxicillin with clavulanic acid	Clavulin
ampicillin

How It Works

These antibiotics kill the bacteria that commonly cause urinary tract infections (UTIs). Amoxicillin is taken by mouth (orally). Ampicillin is taken by mouth or given by injection.

Why It Is Used

These forms of penicillins treat uncomplicated urinary tract infections. These are infections that are not caused by a blockage or structural problem or some other medical condition that affects urinary function, such as diabetes.

How Well It Works

These forms of penicillins are effective against a broad range of bacteria. Relief of symptoms of a urinary tract infection should occur within 2 to 3 days of treatment.

Side Effects

Common side effects are:

• Skin rashes.
• Upset stomach.
• Altered taste.
• Nausea.
• Diarrhea.

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

What To Think About

Antibiotic resistance

Be sure to take all of the medication your doctor gives you, even if you are feeling better. If you do not take all of your antibiotics 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 not only makes antibiotics less effective but also makes bacterial infections more difficult to treat.

Antibiotic resistance among bacteria that cause UTIs has increased steadily in recent decades. You and your doctor may have to try different antibiotics, and different combinations of antibiotics, to find the right medication that will kill the bacteria causing your UTI. Before you start a new antibiotic, your doctor may use results of urine tests to help select a medication.

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Author:	Kathe Gallagher, MSW Carrie Henley	Last Updated: July 26, 2007
Medical Review:	Anne C. Poinier, MD - Internal Medicine E. Gregory Thompson, MD - Internal Medicine Philip Belitsky, MD, FRCSC - Urology
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