The chemistry of new antibiotics

Efficacy of cephalexin two vs. three times daily vs. cefadroxil once daily for streptococcal tonsillopharyngitis

The purpose of this study was to compare the bacteriologic and clinical efficacy of oral cephalexin twice vs. three times daily vs. cefadroxil once daily as therapy for group A beta-hemolytic streptococcal (GABHS) tonsillopharyngitis. A prospective open-label, observational cohort study was conducted over 18 months (January 2000-June 2001). Children enrolled had an acute onset of symptoms and signs of a tonsillopharyngeal illness and a laboratory-documented GABHS infection. Follow-up examination and laboratory testing occurred 21 +/- 4 days following enrollment. Two hundred seventy-one patients were enrolled (intent to treat group): 63 received cephalexin twice daily, 124 received cephalexin three times daily, and 84 received cefadroxil once daily. Fifty-three children did not return for the follow-up visit, leaving 218 patients in the per-protocol group: 54 cephalexin twice-daily treated, 94 cephalexin 3-times daily treated, and 70 cefadroxil once-daily treated. In the per-protocol group, bacteriologic cure for those treated with cephalexin twice daily was 87%, for cephalexin 3 times daily, it was 81% and for cefadroxil once daily it was 81% (p = 0.61). The clinical cure rate for cephalexin twice-daily treatment was 91%; for three-times daily, it was 86%; and for cefadroxil once daily, it was 84% (p = 0.56). Because treatment allocation was not randomized, logistic regression analysis was used to adjust for treatment group differences. Younger age of patient was significantly associated with bacteriologic (p = 0.04) and clinical (p = 0.01) failure independent of treatment group but in the adjusted logistic model no differences were found among the 3 treatment regimens. Cephalexin dosed twice daily or three times daily and cefadroxil dosed once daily appear equivalent in bacteriologic and clinical cure of GABHS tonsillopharyngitis.

Open-Label, parallel-group, multicenter, randomized study of cefprozil versus erythromycin in children with group A streptococcal pharyngitis/tonsillitis

BACKGROUND

Cefprozil and erythromycin are acceptable alternatives to penicillin in the treatment of pharyngitis/tonsillitis due to group A beta-hemolytic streptococcus (GABHS).

OBJECTIVE

The purpose of this trial was to determine the relative efficacy and tolerability of cefprozil and erythromycin in the treatment of pediatric pharyngitis/tonsillitis due to GABHS.

METHODS

This trial compared the bacteriologic and clinical efficacy of erythromycin and cefprozil in children 2 to 12 years of age with culture-documented GABHS pharyngitis/ tonsillitis. Children who were allergic to penicillin, cefprozil, or erythromycin were excluded. Patients were prospectively randomly assigned to receive 10 days of oral therapy with either cefprozil suspension 15 mg/kg per day in 2 divided doses or erythromycin ethylsuccinate suspension 30 mg/kg per day in 3 divided doses. Primary efficacy end points were bacteriologic and clinical response 2 to 8 days after treatment ended. The frequency and severity of adverse events and their relationship to treatment were also assessed.

RESULTS

A total of 199 patients were enrolled and treated (cefprozil, 99; erythromycin, 100); 12 patients in the cefprozil group and 15 in the erythromycin group were not evaluable. The GABHS eradication rate was significantly higher with cefprozil (95%) than with erythromycin (74%) (P = 0.001). The posttreatment carrier rate was lower in the cefprozil group (5%) than in the erythromycin group (18%) (95% CI, -22.3 to -3.8). Clinical cure rate was 90% (78/87) with cefprozil and 91% (77/85) with erythromycin (P = 0.95) (treatment group difference, -0.93; 95% CI, -9.9% to 8.0%). The overall incidence of drug-related adverse events was not significantly different in the 2 groups (11% with cef- prozil, 18% with erythromycin). The most common adverse events were diarrhea and vomiting. Two patients in the erythromycin group discontinued therapy because of adverse events.

CONCLUSIONS

The bacteriologic eradication rate was significantly greater with cefprozil compared with erythromycin in children with pharyngitis/tonsillitis. Both cefprozil and erythromycin produced a clinical cure in >90% of patients.

Diagnosis of penicillin, amoxicillin, and cephalosporin allergy: reliability of examination assessed by skin testing and oral challenge

The specificity of pediatrician-diagnosed allergy reactions to penicillin, amoxicillin, and oral cephalosporins, which was based on contemporaneous examination of the patient, was evaluated by an elective skin testing program. Children and adolescents (n = 247) experiencing an adverse reaction to penicillin, amoxicillin, and/or an oral cephalosporin sufficient to lead to the recommendation to avoid further use were enrolled. Skin testing with penicillin G, commercial benzylpenicilloyl phosphate, penicillin minor determinate mixture, ampicillin, cefazolin, cefuroxime, and ceftriaxone was performed according to the suspected drug allergy followed by an oral challenge, repeat testing, and prospective follow-up if no reactions were observed. Overall, 84 (34.0%) of 247 patients had an IgE-type reaction on skin testing or oral challenge. Twenty-seven (32%) of 85 suspected penicillin reactions, 53 (34%) of 156 suspected amoxicillin reactions, and 13 (50%) of 26 suspected cephalosporin reactions were shown to be IgE mediated. Positive skin tests were observed in 20 patients with non-IgE-type clinical adverse reactions, including 15 patients with only a pruritic polymorphous rash. No reactions to oral challenge were severe after negative skin testing. One hundred sixty-three patients received multiple treatment courses with beta-lactam antibiotics after a negative skin testing procedure and three (1.8%) had adverse IgE reactions, all of which were mild. Physician-diagnosed allergic reactions to beta-lactam antibiotics based on patient examination at the time of the reaction is more accurate than patient history alone but still overestimates the rate of possible true allergy in 66% of patients. Elective penicillin, amoxicillin, and cephalosporin skin testing and oral challenge protocols are necessary to identify patients not at risk.