Antibiotics for a UTI: which medicines are used and how the choice is made

When bacteria cause a urinary tract infection (UTI), the medicine that treats it is an antibiotic, and always by prescription. Over-the-counter pills for the burning do not cure the infection (more on those below). Leftover antibiotics from another illness, or ones prescribed to someone else, are not a safe substitute.

There is no single antibiotic for every UTI. The choice depends on where the infection is (the bladder or the kidneys), who you are (a woman who is not pregnant, someone who is pregnant, a man, a child), your allergies, your past infections and the medicines you already take. This page explains the commonly used antibiotic classes in general terms, and the doctor decides which one is appropriate for you, if any, after evaluating you.

For symptoms and how the visit works, see the UTI page.

For simple cystitis (a bladder infection) in a woman who is not pregnant and has no other health problems, the IDSA/ESCMID guideline (infectious-disease societies of the U.S. and Europe) names these options. This is general information, not a prescription:

Two people with the same burning can need different medicines. The doctor asks when the symptoms started, whether there is fever or back pain, whether you could be pregnant, whether it has happened before, which antibiotics you took in recent months and what you are allergic to. That history rules out options that do not fit you.

In many women with a simple bladder infection the diagnosis is made from symptoms. In other cases it helps to confirm with a urinalysis or a urine culture, which identifies the bacteria and shows which antibiotics work against it. A culture helps most when the infection keeps coming back, when the first treatment does not work, or when there is a risk of complications. When the doctor thinks it will help, we give you a lab order for a lab near you, and she goes over the result with you.

The doctor may ask for a culture before deciding on treatment, especially in pregnancy, in men, with diabetes or a weakened immune system, or if you were already given an antibiotic and the symptoms continue.

Not every UTI is simple cystitis. In these cases the plan can change: a different antibiotic, a longer course, a urine culture before starting, or an in-person exam.

Phenazopyridine is a urinary pain reliever. Some versions are sold without a prescription at the pharmacy. According to MedlinePlus, it eases pain, burning and the urgent need to urinate, but it is not an antibiotic and does not cure the infection. It can turn the urine orange-red, which is harmless. If your symptoms continue you need an evaluation; do not rely on the pain reliever alone.

Dr. Diana Nieves Castro, a general practice physician licensed in Puerto Rico, sees you in English or Spanish. Here is how it works:

Finish the whole course even if you feel better, and drink plenty of water. According to MedlinePlus, bladder-infection symptoms almost always go away within 24 to 48 hours of starting treatment. If you are not better by then, or you get worse, tell the doctor in a follow-up visit. If you develop swelling of the face, lips or tongue, hives or trouble breathing, get emergency care.

Common antibiotic side effects are nausea, diarrhea and rash. Severe, frequent diarrhea during or after treatment should be checked. If UTIs keep coming back, tell the doctor: she can order a urine culture and go over what is going on with you. If what you have is needing to urinate often without burning, see frequent urination.

A UTI is handled in a doctor visit, with the same price for every age and no membership. There is no extra charge for a prescription, and a doctor's note after your visit is included. You are charged when you request the visit, with a full refund if the clinic can't see you. The lab and the pharmacy charge separately. See pricing. The service is run by The Health Initiative, a nonprofit.