Best antibiotics for UTIs in females

For people assigned female at birth, a urinary tract infection (UTI) is a common and unpleasant condition. Anyone can get a UTI, but they are more common in females. The symptoms include a burning sensation while urinating, increased frequency of urination, and feeling an urgent need to urinate—even with an empty bladder. If left untreated, UTIs can move into the kidneys, causing back pain, vomiting, and fever—sometimes requiring hospitalization. Fortunately, many antibiotics work to treat UTIs, and often people begin to feel better within a day or so. Macrobid (nitrofurantoin) is one of the more commonly prescribed antibiotics for UTIs in females. However, choosing the best antibiotic for UTIs in females depends on a few factors. 

First-line antibiotics for UTIs in females

The initial antibiotic chosen to treat a UTI may differ among medical professionals, partly because bacterial resistance to an antibiotic may vary from region to region.“Each region might be a little bit different in terms of resistance. We try to stick with older antibiotics that have been around for a long time and find the one that we think is going to have the least resistance,” says G. Thomas Ruiz, MD, OB/GYN Lead at MemorialCare Orange Coast Medical Center in Fountain Valley, California. 

Healthcare providers in the United States tend to prescribe one of three first-line antibiotics for simple UTIs in females.

Macrobid (nitrofurantoin)

Macrobid (nitrofurantoin mono-macro) is commonly prescribed first for UTI symptoms. “Macrobid is a really good antibiotic for UTIs,” says Dr. Ruiz. For an uncomplicated UTI, the dose is twice a day for five days, which can make it more likely for patients to take the full course correctly in comparison to a seven-day antibiotic. However, Macrobid is not prescribed when there is concern about infection in the kidneys.

Septra or Bactrim (sulfamethoxazole-trimethoprim)

Bactrim and Septra are sulfa-based antibiotics that are usually prescribed twice a day for a week. These have long been considered the standard treatment for acute and recurrent UTIs for their effectiveness, low cost, and tolerability. However, there is more bacterial resistance to these antibiotics in some regions.

Monurol (fosfomycin) 

Monurol (fosfomycin) is specifically for bladder infections and comes in a powder instead of a pill. It can be more expensive than other antibiotics, so it is not always people’s first choice, though you can use a SingleCare discount card to reduce the price. 

Other commonly prescribed antibiotics for UTIs in females

If those antibiotics can’t be prescribed, the next options are oral beta-lactams, which are used for different types of bacterial infections and are one of the most commonly prescribed drug classes. 

Amoxicillin 

Amoxicillin is in the penicillin family and works on many types of infections. But since 10% of U.S. patients report having had an allergy to penicillin, it’s not always the first choice. And since it’s used for various kinds of infections, bacteria in the body can become resistant over time.

Ampicillin 

Ampicillin, which is very similar to amoxicillin, isn’t usually the first choice, either. That’s because the dosage of ampicillin is usually taken every six hours for at least seven days. “The longer you take an antibiotic, the lower the compliance and the less likelihood that you’ll finish the treatment,” says Dr. Ruiz, since not finishing a course of antibiotics promotes bacterial resistance.

Keflex (cephalexin)

Keflex (cephalexin) is another secondary antibiotic for UTI treatment. It is often one that doctors switch patients to if a urine culture indicates the strain of bacteria is resistant to the antibiotic prescribed as a first line of treatment. 

Rocephin (ceftriaxone)

Rocephin (ceftriaxone) is another cephalosporin-class drug, a type of medication that’s similar to penicillin and used for many types of bacterial infections. It is injectable, so it’s not used as a first choice since a nurse or healthcare provider has to administer it. And because it treats a wide range of bacteria, it may lead to bacterial resistance over time. 

Antibiotics for complicated UTIs in females

A complicated UTI is one that occurs in immunocompromised patients, involves the kidneys, or is associated with sepsis, fevers, stones, catheters, or urinary obstruction. Pregnancy is considered another high-risk condition because UTIs are associated with preterm labor. However, a healthcare provider will choose an antibiotic that is safe to use in pregnancy. In general, complicated UTIs are associated with a higher risk of treatment failure and require longer antibiotic courses. Some antibiotics that are generally reserved for complicated UTIs include Cipro (ciprofloxacin) and Levaquin (levofloxacin).

Cipro (ciprofloxacin)

Cipro is the most popular fluoroquinolone-classified antibiotic, which Dr. Ruiz says should be reserved for use on “complicated UTIs that are resistant to everything else.” The reason they use this one last is that “you don’t want someone to get a resistance to an antibiotic and then nothing else works.” 

Levaquin (levofloxacin)

Levaquin is used for many types of infections, including UTIs. Like Cipro, it’s also a fluoroquinolone antibiotic, so it’s not commonly used as a first choice in order to avoid the development of bacterial resistance. 

Side effects of common UTI antibiotics

Antibiotics generally work well for UTIs. But as with any medication, there may be side effects. Some of the more common effects that may occur with UTI antibiotics include:

• Upset stomach, nausea, vomiting 
• Diarrhea 
• Photosensitivity
• Vaginal yeast infection 
• Change in the color of the urine

Serious side effects include severe diarrhea or signs that you are allergic to the medication, such as rash, trouble breathing, or swelling. Contact your healthcare provider immediately if you experience these side effects. 

How do antibiotics treat UTIs? 

UTIs occur when bacteria enter the urethra and infect the urinary tract. Females get UTIs more frequently than males because the urethra is shorter and closer to the rectum, according to the Centers for Disease Control and Prevention. 

Factors that contribute to UTIs in females include:

• Sexual activity
• Not urinating after sexual intercourse
• Using diaphragms, vaginal rings, or spermicide
• Overwashing or douching
• Wiping from back to front
• Pregnancy
• Wearing tight clothing, which can trap heat and bacteria
• Dehydration
• Infrequent urination
• Anatomic variation, such as a short urethra
• Abnormalities in the urinary tract
• Medical conditions like diabetes, obesity, and sickle cell anemia
• Using a catheter 
• Bacterial resistance to medication
• Menopause
• Uterine prolapse, often caused by childbirth 

When prescribed an antibiotic, it goes to work fairly quickly. “Antibiotics work to treat UTIs by killing the bacteria or stopping the bacteria from growing,” says Monte Swarup, MD, a board-certified OB/GYN in Chandler, Arizona, and founder of HPV HUB. 

More specifically, “Antibiotics work by blocking bacterial growth processes, like DNA and protein synthesis. Therefore, the bacteria cannot continue to grow and will die,” says Juana Hutchinson-Colas, MD, Professor of Obstetrics, Gynecology, and Reproductive Sciences at Rutgers Robert Wood Johnson Medical School. Healthcare providers will consider the type of bacteria, likelihood of resistance, and other health factors when choosing an antibiotic to treat a UTI. The most common UTI bacteria is E.coli.

How long do antibiotics take to treat a UTI? 

Once you start treatment, most people feel better quickly. “Antibiotics are very effective, and most of the time, symptoms will take one to two days to go away,” says Dr. Swarup. However, you still need to take the entire course of antibiotics, which may be several pills over the course of five to ten days. Failure to complete the dose could mean a return of symptoms or for your infection to become resistant to antibiotics, making it harder to treat. 

Phenazopyridine, like the OTC drug Azo, may help relieve pain and discomfort of UTIs, but it is not an antibiotic and will not cure the infection. 

If your UTI has been fully treated, you’ll notice a complete absence of symptoms, and symptoms should not come back. A urine culture can determine whether or not someone still has a UTI, but if they’ve taken the entire course of antibiotics and are feeling totally better, it is likely gone. If you have a UTI and antibiotics haven’t improved your symptoms, see your healthcare provider. You may need a different antibiotic. 

Tips for preventing UTIs in females

While UTIs occasionally happen without any triggers, their frequency can be reduced with certain lifestyle modifications: 

• Staying hydrated
• Urinating when you feel the urge instead of holding it
• Urinating after sexual intercourse
• Wiping from front to back
• Wearing loose, breathable clothing
• Drinking cranberry juice or taking cranberry pills

If UTIs continue to occur frequently even with precautions and lifestyle adjustments, some people may need antibiotic prophylaxis—daily antibiotics used to prevent infection before it occurs. Antibiotic prophylaxis can help prevent recurrent UTIs, but it is preferable to use alternative means first in order to avoid developing resistance.

Choosing the best antibiotic for female UTIs

There are a few ways doctors choose the best antibiotic when treating a UTI. Before prescribing an antibiotic, a healthcare provider will likely order a urine culture. “The original treatment is an ‘educated guess’ on common types of bacteria that cause UTIs in women,” says Dr. Swarup, who adds, “A urine culture and antibiotic sensitivity test should be sent out when the UTI is treated.” The urine culture identifies the type of bacteria causing the infection and which antibiotics the bacteria are sensitive to (i.e., the antibiotics most likely to kill the bacteria). Healthcare providers then use this information to select the most effective antibiotic. 

Dr. Ruiz stresses the importance of getting a culture before treating a UTI, “Before we start on antibiotics, we want a urine culture in case the bacteria is resistant to the antibiotic we start them on.” Since cultures typically take three days to come back with enough information to determine what bacteria are present, doctors usually prescribe an initial antibiotic that is most likely to work best for that patient. If the culture shows that the bacterium is one that doesn’t respond well to that antibiotic, your healthcare provider will switch the medication and you will complete that course. 

Vaginosis and yeast infections are other conditions that can cause burning on urination similar to a UTI. But the treatment is different, so talking with a healthcare provider and getting the right testing is important. 

Doctors use other information to determine which antibiotic to prescribe. “A prescriber must take into consideration the medical history, especially medication allergies,” says Dr. Hutchinson-Colas. Recurrence of UTIs is one factor that may influence their choice. In general, “The best antibiotic to treat UTI in a female should target the most common bacteria that cause urinary infections in a specific geographic area, the medical history, and with the least side effects.” 

If your UTI returns or you have recurrent UTIs, you may be referred to a urologist to get more tailored advice and testing. Most people, however, respond well to one course of antibiotics when taken correctly.