The treatment of urinary tract infections is a complex topic due to differing recommendations based on the patient's age, gender, past medical history, lifestyle, and chance of having acquired antibiotic-resistant strains of bacteria. However, the vast majority of urinary tract infections in the United States are still uncomplicated--for example, not associated with infections in the kidney or sexually trasmitted infections--and caused by a bacteria known as E. coli. In these cases the treatment choice becomes more manageable.
Trimethoprim/Sulfamethoxazole
Historically, the combination of trimethroprim and sulfamethoxazole--also known as Bactrim--has been a first-line agent in the treatment of various infections. The combo is cheap, effective and easily reaches body compartments, such as the bladder and inner ear, which some antibiotics have difficulty reaching. Unfortunately, resistance to this medication is increasing across the United States. According to the "Journal of the American Medical Association," "Resistance to TMP/SMX has been reported at over 30 percent in the western United States, up to 14 percent in the midwest, and around 7 percent in the east." In areas where resistance has increased above 10 percent, it may be more cost-effective to use a more expensive drug because of the chance that treatment with Bactrim will fail.
Fluoroquinolones
Fluoroquinolones such as ciprofloxacin, ofloxacin and levofloxacin are generally the first-line choice where resistance to Bactrim is high. This is because they are the choice most suitable for short-treatment regimens and are effective against a wide range of bacteria. However, these drugs are significantly more expensive than Bactrim and their increased use in recent years has led to more resistance. In addition, they cannot be used in pregnant women due to risk of injury to the fetus.
Nitrofurantoin
Nitrofurantoin is a unique antibiotic that effectively sterilizes the urine of bacteria. Its use is increasing because of concerns about resistance to Bactrim and the fluoroquinolones. In addition, it is safe to use in pregnancy. The main downside to nitrofurantoin is that it has not been shown to be effective during short-treatment regimens. According to the "Journal of Antimicrobial Chemotherapy," "high-dose, shorter-duration antibiotic regimens may reduce the pressure on the emergence of antibiotic resistance." Essentially, the longer a patient is on an antibiotic drug the greater the chance of developing resistance to that drug. Hence, more emphasis is being placed on prescribing antibiotics that eradicate infections quickly.
References
- "Harrison's Principles of Internal Medicine, 17th ed."; Anthony S. Fauci, Eugene Braunwald, Dennis L. Kasper, Stephen L. Hauser, Dan L. Longo, J. Larry Jameson, and Joseph Loscalzo, Eds.; 2008
- "Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11th ed."; Laurence L. Brunton, editor-in-chief; 2006
- "The Journal of the American Medical Association"; Comparison of Ciprofloxacin (7 Days) and Trimethoprim-Sulfamethoxazole (14 Days) for Acute Uncomplicated Pyelonephritis in Women; Talan DA, Stamm WE, Hooton TM, et al; 2000
- "Journal of Antimicrobial Chemotherapy"; Prior antibiotics and risk of antibiotic-resistant community-acquired urinary tract infection: a case–control study; Sharon Hillier, Zoe Roberts, Frank Dunstan, Chris Butler, Anthony Howard and Stephen Palmer; April 2007
