Urinary tract infections are painful conditions caused by bacterial infection of the urinary tract. Each year, urinary tract infections are the reason behind approximately 8.3 million visits to the doctor, according to the National Kidney and Urologic Diseases Information Clearinghouse. To kill the bacteria causing the infection, doctors often prescribe antibiotic medications. Men and women are generally treated similarly. The type of antibiotic used depends on several factors, including the severity of the infection, the type of bacteria causing the infection and drug resistance of the bacteria.
Trimethoprim-Sulfamethoxazole
Trimethoprim-sulfamethoxazole, abbreviated as TMP-SMX, is a combination of two drugs that is now the most common treatment for urinary tract infections in men, explains the University of Maryland Medical Center. Doctors usually prescribe TMP-SMX for 3 days, longer treatments do not work better and increase the risk of side effects. TMP-SMX is not recommended for patients who recently had dental surgery or who are allergic to sulfa drugs. For patients who are allergic to sulfa drugs, trimethoprim is sometimes prescribed alone.
Penicillins
Penicillins, particularly amoxicillin, used to be the most common medication for treating urinary tract infections. However, because it was so widely used, approximately 25 percent of infections caused by the bacteria E. coli are now resistant to penicillins, according to the University of Maryland Medical Center. The standard course of treatment with amoxicillin is a 10-day prescription. In some cases, amoxicillin is combined with another drug, clavulanate, to increase it's effectiveness.
Fluoroquinolones
Fluoroquinolones, which are also called quinolones, are growing in use for infections that have become resistant to both penicillins and TMP-SMX. Commonly prescribed quinolones are ofloxacin, ciprofloxacin, norfloxacin and levofloxacin.
Cephalosporins
The use of cephalosporins has also increased in recent years as an alternative to penicillins. Cephalosporins belong to the class of drugs known as beta-lactams, which is the same class that includes penicillins. Types of cephalosporins available are cephalexin, cefadroxil, cefuroxime, oracarbef and cefixime. Another type of beta-lactam, pivmecillinam, is also commonly prescribed to treat urinary tract infections in Europe.
Additional Antibiotics
Aminoglycosides, including gentamicin, tobramycin and amikacin, are often used to treat very severe urinary tract infections. These medications are very powerful, and can cause serious side effects, such as damage to the kidneys, hearing and sense of balance. Tetracyclines, such as doxycycline, tetracycline and minocycline, are usually prescribed to treat urinary tract infections cause by bacteria other than E. coli, such as Mycoplasma or Chlamydia. Nitrofurantoin is another antibiotic used in cases where the bacteria are resistant to TMP-SMX. This drug must be taken for at least seven days, and causes more side effects than TMP-SMX. A recently developed drug, doripenem, is another option that can only be administered as an injection.
References
- University of Maryland Medical Center: Urinary tract infection - Medications
- Medline Plus: Urinary Tract Infection--Adults
- National Kidney and Urologic Disease Information Clearinghouse:Urinary Tract Infections in Adults
- GeorgiaHealthInfo.gov: Urinary Tract Infection
- Penn Satege College of Medicine: Urinary Tract Infections (UTI)
