Comparative study of cefaclor and amoxicillin in treatment of urinary tract infection

Correlation between pharmacokinetic/pharmacodynamic parameters and efficacy for antibiotics in the treatment of urinary tract infection

Antibiotic treatment of urinary tract infection (UTI) depends on the antibiotic being able to inhibit the growth or to kill the bacteria present in the urinary tract. The pharmacokinetics of antibiotics in the urinary tract including the kidneys, the bladder and the prostate are briefly reviewed. The conclusion is that high urinary antibiotic concentrations can eradicate bacteria in the urine, but in the kidney tissue levels must surpass the MIC of the infecting pathogen to achieve effect. Pharmacodynamic studies in UTI are relatively scarce, but recent studies have shown, that as for other types of infections, beta-lactam antibiotic treatment of UTI depends on the T(>MIC), i.e. the time the antibiotic concentration remains above the MIC. This counts for activity against bacteria in the kidneys as well as in the urine. Bacterial counts in the bladder are curiously resistant to the activity of most antibiotics. For drugs with concentration dependent time-kill activity such as the fluoroquinolones and the aminoglycosides, the effect in UTIs is dependent on the peak/MIC ratio or AUC/MIC ratio. The aminoglycosides are difficult to evaluate in this context, since they are bound in high concentrations to the renal cortex. For clinical studies the author reviews the literature for aminopenicillins (ampicillin and amoxycillin) as representatives of beta-lactam antibiotics. Data from 16 studies of uncomplicated UTI encompassing 20 treatment groups showed a significant correlation between the cumulative T(>MIC) and bacteriological cure, such that a cumulative T(>MIC) of 30 h was necessary for a maximal cure rate of 80-90%. Incorporating these data including the T(>MIC) for the aminopenicillins, the optimal dose with minimal consumption of drug can be calculated, i.e. for amoxycillin 500 mg TID for 4 days. Further research is needed to calculate optimal dosages for other types of antibiotics, especially in order to prevent development of resistance.

Loracarbef versus cefaclor in the treatment of urinary tract infections in women

In a double-blind, prospective, randomized study, 108 college women with acute urinary tract infections were treated for 7 days with either loracarbef (LY163892) at 200 mg once daily (n = 53) or cefaclor at 250 mg three times daily (n = 55). The cure rates at 5 to 9 days after treatment in the loracarbef and cefaclor groups were 96 and 90%, respectively. Both loracarbef and cefaclor are safe, well tolerated, and effective in the treatment of urinary tract infections in women.

Prospective comparison of amoxicillin-clavulanic acid and cefaclor in treatment of uncomplicated urinary tract infections

Patients with acute, uncomplicated urinary tract infections were treated with either amoxicillin-clavulanic acid (A-C) in fixed combination or cefaclor for 10 days in a prospective randomized comparison. The A-C group included 29 women and 1 man (mean age, 25.5 years), and the cefaclor group included 35 women and 1 man (mean age, 24.9 years). The cure rates were 26 (87%) of 30 with A-C and 26 (72%) of 36 with cefaclor (P greater than 0.20). There was one failure in each group, each caused by an isolate resistant to ampicillin. There were one relapse and two reinfections in the A-C group, compared with seven relapses and two reinfections in the cefaclor group. Side effects, including patients started on antibiotics but whose cultures did not confirm urinary tract infections, were diarrhea in 7 (16%) and rash in 1 (2%) of 44 A-C patients, compared with diarrhea in 1 (2%) and yeast vaginitis in 3 (6%) of 48 cefaclor patients. Although the A-C group had a greater proportion of antibody-coated bacterium-positive infections (22 versus 18 with cefaclor), there was a lower recurrence rate with fewer relapses in patients treated with A-C.

Cefaclor pharmacokinetic parameters: serum concentrations determined by a new high-performance liquid chromatographic technique

Pharmacokinetic parameters of cefaclor were studied in eight patients after an oral dose of 250 mg. Serum samples were obtained before and on 19 occasions after oral administration. Cefaclor serum concentrations were determined by a new high-performance liquid chromatographic technique.

Single-dose cefaclor therapy of urinary tract infection. Evaluation of antibody-coated bacteria test and C-reactive protein assay as predictors of cure

The efficacy of single-dose (cefaclor, 2 g orally) and multidose (cefaclor, 250 mg orally three times a day for 10 days) antibiotic regimens in the therapy of acute uncomplicated urinary tract infections (UTI) in nonpregnant women were compared. The patient's clinical status and results of urine cultures were compared in retrospect with the results of the antibody-coated bacteria (ACB) test and C-reactive protein (CRP) test in order to determine if either test would predict the patient's response. Overall, 10 of 30 patients (33 percent) and 18 of 22 patients (81 percent) given single doses and multidoses, respectively, had negative urine cultures four weeks after completion of therapy. A negative urine culture at four weeks correlated with a negative ACB test utilizing the less inclusive criteria for negativity (less than 5 bacteria with fluorescence in 5 minutes of search) but not with a negative ACB test utilizing the more inclusive criteria (less than 10 percent bacteria with fluorescence) or with a negative CRP test. The cure rate in the ACB-negative single-dose group (7 of 9 patients) utilizing the less inclusive criteria for negativity was similar to the cure rate in the ACB-negative multidose group (8 of 10 patients). This study suggests that the ACB test, if properly standardized, might permit identification of a population of patients with UTI who would respond to single-dose cefaclor therapy.

Update on the treatment of bacterial urinary tract infections

The treatment of urinary tract infections (UTIs) has become a complex problem for the clinical practitioner. An understanding of the pharmacology, pharmacokinetics, and in vivo biological activity of antimicrobial agents is needed, as is an understanding of the variables that may influence patient compliance with medication regimens. Although UTIs are usually treated for 10 to 14 days, shorter treatment schedules of seven to ten days or even single-dose regimens are possible. Guidelines for the treatment of UTIs are presented along with suggestions for increased patient compliance.