Which Antibiotics Work Best for UTIs?

Written by Brendan Levy, MD

Should I be taking Macrobid (nitrofurantoin), Bactrim, Monurol, Keflex, Cipro or something else?

What type of urinary tract infection (UTI) are we talking about?

When doctors say “UTI,” they can mean any infection of the urinary tract (bladder, urethra, ureters, kidneys, etc.). However, usually they mean simple, uncomplicated, acute cystitis in a young woman. Let’s break down the five parts of that sentence:

  • Simple and uncomplicated implies that the woman is not pregnant, diabetic, or immunocompromised, and hasn’t had recent bladder surgery — or anything else that might make the situation trickier.
  • Acute means it’s an infection that has just started and has lasted less than about 10 days, not something that’s been going on for weeks or months.
  • Cystitis means it’s an infection of the bladder and not the kidneys or other more serious UTI types.
  • Young this usually means someone under 65 years old — older patients can get UTIs that are different and sometimes don’t even cause pain but can cause symptoms like delirium or confusion.
  • Woman men generally have a much lower risk of UTIs because they have longer urethras, so when they do get one, they require different testing and treatment than normal UTI cases in women.

Okay - so how do you treat a UTI (acute uncomplicated cystitis)?

There are a few antibiotics we usually start with. We choose them because they tend to have a lower risk of side effects and because they are effective at killing the bacteria and helping to cure a UTI. Overall, we always think about a risk and benefit ratio (i.e., what is the benefit you get, and how big is the risk you take for that benefit?). Here are some of the most commonly prescribed antibiotics for UTIs:

  • Macrobid (nitrofurantoin) is now one of the most recommended antibiotics because it has fewer serious side effects, doesn't disturb your good bacteria as much, and can kill most UTI bacteria. It is considered relatively pregnancy safe in the second and third trimesters.
  • Bactrim (sulfamethoxazole-trimethoprim) is a sulfa antibiotic and is also most commonly used.
  • Cipro (ciprofloxacin) was, until recently, the most popular antibiotic for UTI treatment. It is still used, but more bacteria are resistant to it and doctors have learned more about serious side effects including heart problems and tendon rupture, so it’s no longer the first choice. Cipro does get into the kidneys better than some other antibiotics,so it is still used in the treatment of kidney infections.
  • Keflex (cephalexin) is a cephalosporin antibiotic that is increasingly used for UTIs, especially where there is any concern for a kidney infection. In this role, it partly replaces ciprofloxacin.
  • Monurol (fosfomycin) is a powder that you mix and usually requires only one dose. It’s a great option and can be used by people who can’t swallow pills, but unfortunately many pharmacies don’t carry it.

If you have a UTI, talk to your doctor about what antibiotic is best for you. Even if you used a certain medicine in the past, changing bacterial resistance patterns, as well as changes in our understanding of each drug, may cause your doctor to recommend something new.

The views expressed in this article intend to highlight alternative studies and induce conversation. They are the views of the author and do not necessarily represent the views of HeyDoctor, and are for informational purposes only, even if and to the extent that this article features the advice of physicians and medical practitioners. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment, and should never be relied upon for specific medical advice.

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