New Help for Urinary Tract Infections
Zamula, Evelyn, FDA Consumer
Though men don't escape urinary tract infections - especially as they age and their prostates cause problems - women get the lion's share of UTIs, about 25 times more often than men. Most of these infections are uncomplicated: They occur in otherwise healthy women and girls who have normal urinary tracts and normal urinary functioning and no underlying physical problems.
The National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health estimates that by age 30, half of all women experience at least one UTI, and about 20 percent of these women will have recurrent UTIs. Each year, UTIs are responsible for more than 6 million doctor visits and about $4.5 billion in health-care costs. Only upper respiratory tract infections account for more absenteeism in working women.
The urinary tract consists of the kidneys, ureters, bladder, and urethra. The kidneys - bean-shaped organs weighing about 4 to 6 ounces in the adult and located below the ribs toward the middle of the back - filter liquid waste from the blood that passes through them to produce urine. Urine passes from the kidneys down through two narrow tubes called ureters to the bladder, a triangular-shaped organ in the lower abdomen. The bladder acts as a reservoir for urine until it is emptied out through the urethra, a tube leading from the bladder to outside the body.
When limited to the urethra, an infection of the urinary tract is called urethritis. More often than not, however, bacteria travel up a woman's one-and-a-half-inch-long urethra to the bladder, where they may cause cystitis, the most common urinary tract infection. A more serious condition called pyelonephritis results when bacteria from the bladder ascend to the kidneys via the ureters.
Before the modern drug era, doctors prescribed the urinary antiseptic Mandelamine (methenamine mandelate), cranberry juice, and diets that acidified the urine to prevent and treat recurrent UTIs. In many cases, this treatment was ineffective, and women who had recurrent UTIs ultimately suffered kidney failure. By the 1940s, the antimicrobial sulfa drugs had been introduced and proved very effective in treating UTIs. The explosive development of broad-spectrum antibiotics that began about the same time with the discovery of penicillin - and continued with the development of tetracyclines, erythromycin and cephalosporins - provided more options in treating UTIs.
In the last few years, FDA has approved a group of drugs called quinolones (including ciprofloxacin [Cipro], enoxacin [Penetrex], norfloxacin [Noroxin], ofloxacin [Floxin], cinoxacin [Cinobac], and lomefloxacin [Maxaquin]) for treating both uncomplicated UTIs and more serious urinary tract disorders. Philip Hanno, M.D., chairman of the urology department and professor of urology at Temple University, Philadelphia, Pa., says that with quinolones, "... you don't have to bring people into the hospital to get good levels of antibiotics that can treat pseudomonas and other gram-negative organisms. Previously, we had to use parenteral antibiotics [intravenous medications]. I do think they're overused, though, and resistance to them is developing."
Each group of drugs affects bacteria in the urine differently, either by interfering with reproduction, or depriving them of certain enzymes necessary for their growth. Successful treatment depends on the concentration of the bacteria-fighting drug in the urine.
Normal urine is sterile. An average adult passes about 3 pints of urine each day, but the amount varies, depending on how much food and drink are consumed.
The urinary system is constructed to repel infection. Valve-like structures at the lower ends of the ureters prevent urine from backing up (called vesicoureteral reflux) into the kidneys, where it could cause damage. When infection occurs, urination helps wash bacteria out of the bladder.
Symptoms of Infection
Sometimes a person can have a UTI without having symptoms. …