Management of lower urinary tract infections.

Most urinary tract infections (UTIs) present as bacterial cystitis in healthy women in the sexually active age group. The commonest pathogen is Escherichia coli and most of the remainder are due to Staphylococcus saprophyticus. Many women are prone to recurrent UTIs and these are invariably due to a reinfection with a different organism. After diagnosis, a curative course of treatment should be given, but the approach should be different if the infection is uncomplicated (normal urinary tract and normal renal function) as opposed to complicated (male patient, abnormal urinary tract, impaired host defence mechanisms, impaired renal function, infection with a virulent organism). It is believed that traditional dosage regimens for uncomplicated UTIs are extravagant. There is no convincing evidence that a long course of medication is more effective than a short one; in fact, the use of single dose therapy for uncomplicated UTIs is gaining support. Trimethoprim 600mg, cotrimoxazole (trimethoprim/sulfamethoxazole) 1.92g, fosfomycin trometamol 3g and the 4-quinolones are the preferred agents for single dose treatment. Failure of single dose therapy is a simple guide for the need for further urinary tract investigation or more intensive therapy. If UTIs recur, it may be necessary to consider long term, low dose prophylaxis. The most effective drugs for this type of treatment include nitrofurantoin 50mg, trimethoprim 100mg and norfloxacin 200mg, given at night. More recent studies show that a dose administered on alternate nights, 3 nights a week or after intercourse is just as effective.