The Best Antibiotics to Treat a UTI

UTI, or urinary tract infection, is a common bacterial infection that can be easily treated with antibiotics 2. The choice of antibiotic depends on the bacteria that are causing the infection, the severity of symptoms, the possibility of complications and the ability of the patient to take medicine by mouth. There are several types of antibiotics to treat a UTI.

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The penicillin antibiotics include ampicillin, amoxicillin and Augmentin 2. Penicillin antibiotics work by disrupting the process used by bacteria to create their cell walls. Some UTI bacteria have become resistant to the effects of penicillin antibiotics. Augmentin is a penicillin antibiotic that tries to circumvent the resistance of these bacteria. It has an added component, called clavulanic acid, which binds and inhibits the proteins used by these bacteria to become resistant to penicillin.

Sulfa Antibiotics

The best-known sulfa antibiotic is Bactrim. Sulfa antibiotics interfere with bacterial growth by inhibiting the production of a specific protein. Sulfa antibiotics were used to treat uncomplicated UTIs until bacteria started becoming resistant to it. As of 2010, its use is limited in areas where the resistance rate is low.


Cephalosporin antibiotics are related to penicillin, and kill bacteria in the same way--by inhibiting cell wall synthesis. Cephalosporins are useful in the treatment of UTIs in patients with penicillin allergies, although there is a small risk of also having an allergy to cephalosporins if you are allergic to penicillin. Also, intravenous cephalosporins, like ceftriaxone, are useful in the treatment of complicated UTIs or pyelonephritis (kidney infections), especially if the patient needs hospitalization or is unable to tolerate medicines by mouth.


Fluoroquinolone antibiotics were developed as alternative antibiotics to the growing penicillin resistance among bacteria. They work by inhibiting the division of DNA at the cellular level, and by making bacterial DNA more fragile and easier to break 2. The most common fluoroquinolone antibiotic is ciprofloxacin. It can be taken by mouth or via an IV. It is useful in the treatment of complicated UTIs or pyelonephritis. Unfortunately, its use is limited to adult patients, as there is some evidence of damage to the cartilage of weight-bearing joints in children using this antibiotic.