,

viewpoints

LONG-TERM THERAPY OF URINARY TRACT INFECTIONS

Dr Calvin Kunin comments on the study of Freeman et aL, on treatment of chronic bacteriuria in men [see Therapy Section of this issue] and discusses the therapy of urinary tract infections in general.

He annotates some practical implications for the therapy of urinary infections in male patients: • Work-up should include determination of serum creatinine, prostatic examination, measurement of residual urine, and

an intravenous pyelogram. • The study by Freeman et al., emphasises the importance of removing urinary obstructions in successful therapy. • Initial treatment should be aimed at eradicating the infection. • If this is successful, the patient should be followed closely, but not treated unless there is a recurrence. • With recurrence of infection, in the absence of stones or obstruction, the possibility of a prostatic focus should be

considered. Trimethoprim may be tried to eliminate this focus of infection. • If this fails and recurrence continues, particularly if the same organism is present, long-term suppressive therapy

should be considered. • Emergence of infection during drug treatment requires reassessment of the patient and his therapy.

In general, the management of recurrent urinary tract infection is a more complex problem in male than in female patients. Most urinary infections occur in elderly men who have undergone instrumentation and who may have structural or neurological abnormalities. Recurrence of infection is likely to be due to an infected focus in the kidney or prostate or due to the presence of a foreign body. Long-term treatment may suppress the manifestation of a persistently infection lesion.

Most recurrent urinary infections in women are due to reinfection with different organisms. For women subject to frequent recurrences, bed-time doses with nitrofurantoin or co-trimoxazole, or single doses of antimicrobial agents after intercourse have been tried.

There are many chemotherapeutic agents available for treating urinary infections, and many of them are inexpensive and of low toxicity. The major task in treating urinary infection is to use these agents in the most effective manner. It is now well established that only a short course (1 to 2 weeks) of therapy is necessary to sterilise the normal urinary tract. The most important factor influencing the outcome of treatment is the presence of structural or neurological lesions that interfere with the voiding mechanism.

Kunin, C.M.: Annals oflnternal Medicine 83: 273 (Aug 1975)

I NPHARMA 30th August, 1975 p.2