Urinary Tract Infection (UTI)
How is it treated?
Whether an antibiotic is prescribed to treat a UTI and the choice of antibiotic will depend on several factors. These include the site of the infection (upper tract versus lower tract), the bacterium causing the infection, and any allergies the individual may have to antibiotics. Other considerations include the severity of the infection (complicated versus uncomplicated), the antibiotics used to treat previous infections, and the doctor's or health care provider's knowledge of any apparent antibiotic resistance.
If you have experienced recurrent or frequent UTIs, your doctor may want you to continue taking antibiotics after you have finished treatment for an acute UTI. This is done to prevent future urinary infections. Recurrent lower tract infections may be prevented by taking low doses of Bactrim, trimethoprim, or nitrofurantoin for up to 6 months.
Regardless of the drug chosen, it is important that you complete the antibiotic regimen that your health care provider has prescribed. Many individuals stop taking their medication when they feel better, a course of action that medical practitioners and pharmacists strongly discourage because it can allow an infection to recur with even greater severity within a short time frame. In addition, the bacteria in your system can develop resistance to the antibiotic, and you can spread the resistant bacteria to members of your family and community. If no other antibiotics are available to fight the bacteria, the consequences can be deadly for the infected individuals.
Drugs used to treat Lower Tract Infections
Preferred treatments for uncomplicated lower tract infections (usually 3 days of therapy):
- Trimethoprim-sulfamethoxazole (Bactrim; Septra) -- Bacterial cells produce folic acid, a chemical necessary for their growth. Sulfamethoxazole kills the bacterium by interfering with the enzyme that helps form folic acid. The combination of a sulfamethoxazole with trimethoprim is effective because high levels of the drugs are achieved in the urinary tract and urine, which kills bacteria directly at the site of the infection.
- Quinolones such as ciprofloxacin (Cipro), levofloxacin (Levaquin), and gatifloxacin (Tequin) -- Quinolones are effective in fighting most of the bacteria that cause UTI. This drug class works by interfering with an enzyme that allows bacteria to reproduce, thereby halting the growth of bacteria and eventually leading to their death. Quinolones are eliminated from the body by the kidney, so they go through the urinary tract, killing bacteria at the site of the infection.
Alternative treatments (3-7 days of therapy) for uncomplicated lower tract infections:
- Penicillins such as amoxicillin (Amoxil) and Augmentin -- Penicillins destroy the outer wall of bacteria, killing the bacteria but not harming the body's own cells. Historically, these antiobiotics have been effective in killing many of the bacteria that cause UTIs but more recently, bacterial resistance to these antibiotics is emerging.
- Nitrofurantoin (Macrobid; Macrodantin) -- This drug is effective in killing many of the bacteria that cause UTIs. An added plus is that there have been few reports of bacterial resistance associated with its use.
- Trimethoprim (Primsol) -- Patients who are allergic to sulfonamides (for example, Bactrim, Septra, and trimethoprim-sulfamethoxazole) may be treated with trimethoprim alone. High levels of the drug are achieved in the urinary tract and urine, which helps kill bacteria directly at the site of the infection.
- Fosfomycin (Monurol) -- Fosfomycin, which is generally given as a single dose, is effective in treating organisms that cause uncomplicated UTIs.
The antibiotics described above are also recommended for the treatment of complicated lower tract infections but are generally prescribed for 7 to 10 days. A urinary analgesic such as phenazopyridine (Pyridium) may also be prescribed to treat the pain associated with a complicated UTI.
Drugs used to treat Pyelonephritis
Drugs used to treat uncomplicated upper UTIs (need 7-14 days of therapy):
- Quinolones
- Trimethoprim-sulfamethoxazole
- Penicillins
Drugs used to treat complicated upper UTIs (need at least 14 days of therapy):
- Quinolones
- Extended spectrum penicillins, such as Augmentin
- Aminoglycosides (gentamicin, tobramycin, amikacin)-Aminoglycosides, which have good coverage against Pseudomonas and other bacteria that are resistant to other antibiotics, are usually reserved for serious UTIs and used in combination with other antibiotics.
For serious cases of pyelonephritis that require hospitalization, intravenous (IV) antibiotics are often needed. Hospitalization may also be required if the individual is pregnant or is experiencing nausea, vomiting, or dehydration.
UTIs Caused by a Fungus
If a fungus is found to be the cause of a UTI, then antibiotics will not work. Medications specifically designed to treat fungal infections such as fluconazole, amphotericin, or flucytosine are needed.
Click on the drug class links below to learn more.
Drug classes used to treat Urinary Tract Infection (UTI) Aminoglycosides Antifungal Fosphomycin Nitrofurantoin Penicillins Quinolones Sulfonamides and Related Compounds Trimethoprim
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How is it treated?
