The economic evaluation of antibiotic therapy: relevance to urinary tract infection

Increased treatment failure after 3-days' courses of nitrofurantoin and trimethoprim for urinary tract infections in women: a population-based retrospective cohort study using the PHARMO database

AIM

To assess determinants of treatment failure after antimicrobial therapy of urinary tract infections in women.

METHODS

In primary care 16 703 Dutch women who received a first course (3, 5 or 7 days) of trimethoprim, nitrofurantoin or norfloxacin between 1 January 1992 through 31 December 1997 and who were between 15 and 65 years old at the day of first use were selected. Failure of the initial treatment was defined as a further prescription for one of these three antibiotics or for cotrimoxazole, amoxicillin, ciprofloxacin or ofloxacin, within 31 days after the end of the initial therapy.

RESULTS

Treatment failure rate was 14.4% in patients treated with trimethoprim and nitrofurantoin and 9.6% in patients treated with norfloxacin. A multivariate analysis showed that 5 days'[RR(NIT) 0.67, 95% confidence interval (CI) 0.57, 0.82, RR(TRI) 0.82, 95% CI 0.73, 0.91] and 7 days' (RR(NIT) 0.64, 95% CI 0.53, 0.77, RR(TRI) 0.85, 95% CI 0.71, 1.02) trimethoprim and nitrofurantoin treatment appeared to be more effective than a 3-day treatment (reference category). Other factors increasing treatment failure rates were the age of the patient, the year of therapy and previous hospitalization.

CONCLUSIONS

It may be concluded that 3-day courses of nitrofurantoin and trimethoprim are less effective than 5- and 7-day courses in the treatment of uncomplicated urinary tract infections in women.

Symptomatic vaginal candidiasis after pivmecillinam and norfloxacin treatment of acute uncomplicated lower urinary tract infection

The comparative incidence of symptomatic vaginal candidiasis associated with pivmecillinam and norfloxacin treatment in women with acute symptomatic uncomplicated UTI was determined in two randomised, double-blind, clinical trials. Adverse events reported following general enquiry were reviewed. Presence of Candida vaginitis was based upon the specification as such by investigators, the presence of specific symptoms such as genital pruritus and/or the prescription of specific anti Candida therapy. The incidences of Candida vaginitis were as follows; Study 1 pivmecillinam 200 mg tid for 7 days 13 (4.6%), pivmecillinam 200 mg bid for 7 days 7 (2.4%), pivmecillinam 400 mg bid for 3 days 6 (2.1%) and placebo 6 (2.1%), P=0.19. Study 2 pivmecillinam 400 mg bid for 3 days 7 (1.5%), norfloxacin 400 mg bid for 3 days 20 (4.3%), P=0.016. The incidence of Candida vaginitis in women with acute symptomatic uncomplicated UTI given 3 days treatment with pivmecillinam 400 mg bid is similar to that seen with placebo and is significantly less than the incidence with norfloxacin 400 mg bid for 3 days.

Programs promoting timely sequential antimicrobial therapy: an American perspective

Interventional programs promoting the timely conversion of intravenous to oral antimicrobial therapy have been reported from several hospitals in the U.S.A. and elsewhere. Factors influencing the initiation and conduct of these programs include technological advances, changes in health care delivery or reimbursement, publication of supportive clinical data and growth of clinical pharmacy services. Successful programs employ comprehensive, multidisciplinary strategies to contain antimicrobial-related expenditures using interventions based on structured criteria. Future emphasis on cost-effective drug therapy, advances in computer-based information technology and development of care maps can have favourable influences on the growth of these programs in the U.S.A.

Diagnosis and treatment of uncomplicated urinary tract infection

Acute uncomplicated urinary tract infection is one of the most common problems for which young women seek medical attention and accounts for considerable morbidity and health care costs. Acute cystitis or pyelonephritis in the adult patient should be considered uncomplicated if the patient is not pregnant or elderly, if there has been no recent instrumentation or antimicrobial treatment, and if there are no known functional or anatomic abnormalities of the genitourinary tract. Most of these infections are caused by E. coli, which are susceptible to many oral antimicrobials, although resistance is increasing to some of the commonly used agents. Review of the published data suggests that a 3-day regimen is more effective than a single-dose regimen for all antimicrobials tested. Regimens with trimethoprim-sulfamethoxazole seem to be more effective than those with beta lactams, regardless of the duration. Because of increasing resistance to trimethoprim-sulfamethoxazole, an alternative regimen such as nitrofurantoin (in a 7-day regimen), a fluoroquinolone, or an oral third-generation cephalosporin may be a better empiric choice in some areas. Acute pyelonephritis caused by highly virulent uropathogens in an otherwise healthy woman may be considered an uncomplicated infection. The optimal treatment duration for acute uncomplicated pyelonephritis has not been established, but 10- to 14-day regimens are recommended. We prefer to use antimicrobials that attain high renal tissue levels, such as a fluoroquinolone, trimethoprim-sulfamethoxazole, or an aminoglycoside, for pyelonephritis. Acute uncomplicated cystitis or pyelonephritis in healthy adult men is uncommon but is generally caused by the same spectrum of uropathogens with the same antimicrobial susceptibility profile as that seen in women.