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PubMed1990

Comparison of the effects of food on the pharmacokinetics of cefprozil and cefaclor.

The objective of this study was to assess the effects of food on the pharmacokinetics of cefprozil and cefaclor. A group of 12 healthy male volunteers received a single 250-mg dose of cefprozil or cefaclor under fasting conditions as well as after the intake of food. There was a 1-week washout period between each treatment. Serial blood samples were collected and assayed for cefprozil or cefaclor by specific high-pressure liquid chromatographic methods. The mean +/- standard deviation peak concentration (Cmax) of cefprozil in plasma was 6.13 +/- 1.22 micrograms/ml under the fasting condition and 5.27 +/- 1.06 micrograms/ml after breakfast, and these values were not significantly different from each other. The corresponding median time to reach Cmax was prolonged after food intake, but this difference was not significant. The mean Cmax values of cefaclor decreased significantly from 8.70 +/- 2.72 micrograms/ml under the fasting condition to 4.29 +/- 1.52 micrograms/ml after breakfast, and the corresponding median times to reach Cmax were significantly prolonged. The mean half-lives of cefprozil and cefaclor were nearly identical for the two treatments, suggesting that the elimination kinetics of these cephalosporins remained unaltered when the drugs were administered with food. The area under the plasma-concentration-versus-time curves for fasted and fed conditions were not significantly different for both drugs. The results of this study indicate that the extent of absorption and rate of elimination of both cephalosporins remain unaltered in the presence of food. However, the absorption rate of cefaclor is significantly reduced in the presence of food, while that of cefprozil remains unaltered. As a result, the Cmax of cefaclor is significantly reduced in the presence of food, whereas that of cefprozil is not significantly affected. Cefprozil can be administered with a meal without markedly affecting levels in blood.

Adult↗
PubMed1991

Pharmacokinetics of cefuroxime axetil and cefaclor: relationship of concentrations in serum to MICs for common respiratory pathogens.

The pharmacokinetics of single doses of cefaclor at 250 and 375 mg and cefuroxime axetil at 250 mg administered under optimal conditions (i.e., cefuroxime axetil after food and cefaclor in the fasted state) were studied in 24 healthy male volunteers. Drug concentrations in serum were related to MICs for common respiratory tract pathogens by using data generated from a recently completed national survey. The time the concentrations in serum exceeded the MICs for Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella (formerly Branhamella) catarrhalis were significantly greater (P less than 0.05) for cefuroxime axetil at 250 mg than for cefaclor at 250 or 375 mg. With the recommended dosing regimens (cefuroxime axetil at 250 mg and cefaclor at 375 mg twice daily or cefaclor at 250 mg three times daily), cefuroxime concentrations exceed the MIC for 90% of the strains tested for a greater time period than cefaclor concentrations with either regimen. The reasons for this difference are (i) the greater potency and slower clearance of cefuroxime compared with those of cefaclor and (ii) the greater sensitivity of these pathogens to cefuroxime.

Administration, Oral↗
PubMed1996

Bactericidal activities of cefprozil, penicillin, cefaclor, cefixime, and loracarbef against penicillin-susceptible and -resistant Streptococcus pneumoniae in an in vitro pharmacodynamic infection model.

We examined the bactericidal activities of penicillin, cefprozil, cefixime, cefaclor, and loracarbef against three clinical isolates of Streptococcus pneumoniae which were susceptible, moderately susceptible, and resistant to penicillin. An in vitro two-compartment glass infection model was used to simulate human pharmacokinetics in the presence of bacteria. Also, changes in organism susceptibility and development of resistant subpopulations were evaluated. Simulated pediatric dosage regimens and target peak concentrations in the central compartment were as follows: penicillin V-potassium, 26 mg/kg of body weight every 6 h (q6h) and 14 micrograms/ml; cefaclor, 13.4 mg/kg q8h and 16 micrograms/ml; loracarbef, 15 mg/kg q12h and 19 micrograms/ml; cefprozil, 15 mg/kg q12h and 11 micrograms/ml; and cefixime, 8mg/kg q24h and 4 micrograms/ml. Targeted half-lives of each agent were 1 h for penicillin, cefaclor, and loracarbef; 1.3 h for cefprozil; and 3.5 h for cefixime. Growth controls were performed at two different pump rates, 0.8 and 2.0 ml/min (half-lives = 3.5 and 1 h, respectively). Each isolate demonstrated autolysis at the lower rate which was attributed to a decreased supply of fresh nutrients available to the organisms in the infection compartment. Against the susceptible isolate, the time to 99.9% killing was statistically significant between penicillin V-potassium and both cefaclor and cefixime (P < 0.029). Loracarbef never achieved a 99.9% reduction in the inoculum. At 48 h penicillin, cefprozil, and cefaclor were equivalent in extent of killing. Against the intermediately resistant isolate, cefprozil was superior to all other regimens with respect to rate of killing (P < 0.013) and extent of killing at 24 h (P < 0.0003). At 48 h penicillin, cefprozil, and cefaclor were equivalent in extent of killing. All of the regimens exhibited inferior activity against this penicillin-resistant isolate. A 99.9% kill was never obtained with any of the regimens, nor was there an appreciable decrease in the colony counts. In conclusion, it appears that cefprozil, penicillin, and cefaclor are effective therapies against sensitive and even intermediately sensitive isolates of S. pneumoniae. However, none of the oral therapies appear to be of any benefit against penicillin-resistant isolates. The in vitro model may be an effective tool in evaluating other multiple-dose therapies against this fastidious organism, since the continual supply of fresh medium maintains the viability of S. pneumoniae with minimal stationary-phase autolysis.

Cefaclor↗
PubMedDate not supplied

Cefaclor-associated serum sickness-like disease: eight cases and review of the literature.

OBJECTIVE: To describe the clinical features of serum sickness-like diseases (SSLD) in cefaclor-treated patients. DESIGN: Analysis of a case series spontaneously reported to Lyons Pharmacovigilance Center. SETTING: General and hospital practitioners and the French Network of Regional Pharmacovigilance Centers (FNRPC). PATIENTS: All reported cases with a possible causative relationship between cefaclor treatment and SSLD. MAIN RESULTS: Eight cases of SSLD following cefaclor treatment are described. The clinical features included cutaneous reactions, arthralgias, and moderate hyperthermia. In 50 percent of the patients, hospitalization was required because of incapacitating symptoms. The outcome was benign in all cases following discontinuation of the offending drug. All eight cases were reported in children under five years of age. Among 137 cefaclor-associated drug reactions collected by FNRPC, 27 cases of SSLD have been reported; 23 of these patients were younger than five years of age. A literature survey confirmed the higher reporting of SSLD in children with cefaclor compared with other antibiotics and suggested an incidence of 0.024-0.2 percent of SSLD per drug course of cefaclor. CONCLUSIONS: The case reports and epidemiologic studies confirmed the presumed role of age (patients under five years of age) in cefaclor-induced SSLD and the benign outcome despite severe clinical presentations in some reports.

Cefaclor↗
PubMed1991

Double-blind comparison of cefixime and cefaclor in the treatment of acute otitis media in children.

In a double-blind study cefixime, an oral cephalosporin of the third generation, was compared to cefaclor in the treatment of acute otitis media in 397 children aged 6 months to 12 years. Clinical evaluation was carried out at the beginning, at day 10-12 and day 28-35 after the start of the treatment. Specimens for bacterial culture and sensitivity testings were taken from the nasopharynx at the initial visit. Patients were randomized either to cefixime in a dose of 8 mg/kg/day or cefaclor in a dose 40 mg/kg/day in the proportion of 2 cefixime patients to 1 cefaclor patient. Two daily doses were administered for 7 days. At day 10-12, 93.5% in the cefixime group and 90.5% in the cefaclor group (p = 0.08) were clinically cured or improved. At day 28-35 the rate of cured or improved patients had decreased, mostly due to reinfections, to 90.1% in the cefixime group and to 86.6% in the cefaclor group (p = 0.12), respectively. 375 patients (69.9%) had positive bacterial culture in the nasopharynx of at least one strain of Haemophilus influenzae, Streptococcus pneumoniae, Branhamella (Moraxella) catarrhalis or combinations of these 3.73.6% of the B. catarrhalis strains were beta-lactamase producing and 11.4% of the H. influenzae strains, respectively. All isolated bacteria were sensitive to cefixime. Adverse events were reported in 17.9% in the cefixime and 10.6% in the cefaclor group. Most reactions were of moderate or mild nature and mostly affected skin or the gastrointestinal region. No serious adverse experiences occurred. In view of the good clinical results obtained cefixime seems to be at least as effective as cefaclor in the treatment of acute otitis media in children.

Acute Disease↗
PubMed2002

Comparative study of cefaclor AF vs. cefuroxime axetil in acute exacerbations of chronic bronchitis.

BACKGROUND: Acute exacerbations of chronic bronchitis (AECB) are the most common complication of chronic bronchitis. The majority of AECB are caused by infection. The choice of appropriate antibacterial therapy for AECB is becoming more difficult and is usually empirically. Cefaclor and cefuroxime are used for ambulatory treatment of AECB. MATERIAL/METHODS: This multicenter, randomized, single blind study was undertaken in order to compare efficacy and safety of cefaclor AF (500 mg BID) and cefuroxime axetil (250 mg BID) in 10 days treatment of ambulatory patients with AECB. 170 adults were enrolled into the study. Clinical responses were assessed on 17th-24th day after randomization. RESULTS: Both antibiotics had high over 97% effectiveness in the treatment of AECB. There was statistically significant 1.7 times higher rate of patients with cough release after cefaclor treatment compared to cefuroxime (p<0.03). There was a significantly 2.25 higher rate of patients with AECB symptoms release like: increasing dyspnea, sputum volume and sputum purulence or cough in cefaclor group compared to cefuroxime (p<0.0187). Both treatments resulted in significant improvement of pulmonary peak expiratory flow (PEF). There were no differences between the rates of gastrointestinal and other side effects in both groups. CONCLUSIONS: 1. Cefaclor and cefuroxime have similar high efficacy and safety in 10 days treatment of patients with AECB. 2. Cefaclor treatment significantly higher 2.25 times reduces the rate of principle symptoms of AECB compared to cefuroxime. 3. Both antibiotics treatment significantly increase PEF, with higher tendency observed in after cefaclor treatment.

Adult↗
PubMed2003

Cefaclor AF vs Clarithromycin in acute exacerbation of chronic bronchitis (B3M-PK-AJBG).

OBJECTIVE: To compare the efficacy and safety of Cefaclor AF vs Clarithromycin in the treatment of acute exacerbation of chronic bronchitis in adult subjects. PATIENTS AND METHODS: This study was conducted on 300 patients suffering from acute exacerbation of chronic bronchitis, who attended the out patient clinics of ten different hospitals throughout Pakistan. Pneumonia, bronchiectasis and tuberculosis were excluded with the help of chest radiography and sputum smear examination. Pretherapy sputum culture and sensitivity (c/s) were tested and patients were randomized and supplied with either tablet Cefaclor 375 mg or tablet Clarithromycin 250 mg to be taken twice daily. Patients were evaluated at day 0 and then at day 3-5 and day 10-11. Post therapy sputum c/s was done on day 10-11. A fourth and final visit was planned on day 20-24 which was optional. At each visit, the severity of disease and the signs and symptoms were recorded on the clinical report forms according to the preset standards. RESULTS: Of 136 patients in the Cefaclor group and 142 patients in the Clarithromycin group, cure was achieved in 44 vs 35 subjects, improvement in 78 vs 91 subjects and failure in 16 vs 18 subjects among Cefaclor vs Clarithromycin groups respectively. The overall clinical efficacy (cure and improvement combined ) was 88.4% in the Cefaclor group and 87.5% in the Clarithromycin group. Nine patients in the Cefaclor group and patients in the Clarithromycin group had one adverse event whereas twelve patients in each group had two or more adverse events. CONCLUSIONS: The above results show that both Cefaclor AF and Clarithromycin are equally effective and safe in the treatment of acute exacerbation of chronic bronchitis in adult patients.

Acute Disease↗
PubMed1992

Cefaclor as a prophylactic agent for recurrent urinary infections: a comparative trial with macrocrystalline nitrofurantoin.

Eighty women with recurrent urinary infections (a median of seven episodes per year) were randomized to twelve months prophylaxis with cefaclor 250 mg or macrocrystalline nitrofurantoin 50 mg, at night. Seventy-three patients (37 given cefaclor and 36 given macrocrystalline nitrofurantoin) were assessable for efficacy. The incidence of radiological abnormalities in the two treatment groups was 23% and 30% respectively. Ninety-five percent of the patients taking cefaclor were symptomatically improved during the twelve months of prophylaxis and 86% remained abacteriuric; corresponding figures in the group taking macrocrystalline nitrofurantoin were 86% and 85% respectively. There were 88 breakthrough infections in patients taking cefaclor (6 resistant strains), and 9 in those patients taking macrocrystalline nitrofurantoin (6 by resistant strains). The mean interval between symptomatic episodes on prophylactic therapy increased by 5.6-fold in patients taking cefaclor, and 4.3-fold in those taking macrocrystalline nitrofurantoin. Resistant coliforms were found in only 3 out of 37 patients studied after twelve months prophylaxis; these organisms did not proceed to cause infections. All 80 patients were assessable for adverse events: 5 out of 39 taking cefaclor (12.8%) reported an event "probably" associated with the antibiotic, and 3 (7.7%) stopped taking the drug for various reasons; corresponding figures for macrocrystalline nitrofurantoin were 17.1% and 9.8% respectively. Patients with a radiological abnormality responded well to long-term low-dose prophylaxis with either agent. Cefaclor seems to offer an alternative to macrocrystalline nitrofurantoin for the prophylaxis of recurrent urinary infections in women.

Adult↗
PubMed2004

[Comparative study on cefdinir and cefaclor in the treatment of patients with mild to moderate bacterial community acquired pneumonia].

OBJECTIVE: To evaluate the efficacy and safety of cefdinir in the treatment of patients with mild to moderate bacterial community acquired pneumonia (CAP). METHODS: A prospective single-blind randomized controlled clinical study was performed comparing cefdinir with cefaclor in the treatment of sixty-four patients with CAP. The clinical and bacteriological efficacy and safety were compared between cefdinir and cefaclor in treating mild to moderate CAP. Thirty-three patients were treated with cefdinir 100 mg, orally, three times a day (cefdinir group), thirty-one patients were treated with cefaclor 500 mg, orally, three times a day (cefaclor group). In both groups 7-14 d was a treatment course. RESULTS: The cure rate of cefdinir and cefaclor was 84.8% and 77.4% respectively and the overall efficacy rate was 93.9% and 87.1% respectively. The bacterial positive rates and bacterial eradication rates of the two groups were 81.8%, 80.7% and 96.3%, 88%, respectively. The adverse drug reaction rate were 3% in cefdinir group and 6.5% in cefaclor group. There was no statistical significant difference between the two groups for the above results (P >0.05). The time of given medicine of cefdinir and cefaclor was (10.8 +/- 1.6) d and (12.1 +/- 1.7) d (P <0.01) respectively. CONCLUSION: cefdinir is safe and effective, shorten the course of treatment in the treatment of mild to moderate bacterial community acquired pneumonia.

Adolescent↗
PubMedDate not supplied

Antimicrobial activity in vitro of cefaclor, a new oral cephalosporin.

The antimicrobial activity of cefaclor, a new orally administered cephalosporin derivative, was studied in vitro against a variety of Gram-positive and Gram-negative clinical isolates. Both penicillin-resistant and penicillin-susceptible strains of Staphylococcus aureus were susceptible to cefaclor, with mean MICs of 1.44 and 0.93 microgram/ml, respectively. However, the MBC for penicillin-resistant S. aureus was higher than that for the penicillin-susceptible strains. All strains of Streptococcus pyogenes, Streptococcus viridans, and Streptococcus pneumoniae tested were highly susceptible to cefaclor; all strains of Streptococcus faecalis were highly resistant to cefaclor. Strains of Escherichia coli, Klebsiella sp., Proteus mirabilis, and Hemophilus influenzae were susceptible to cefaclor. Eighty per cent of strains of H. influenzae were inhibited by 5 micrograms/ml of cefaclor. Most strains of Enterobacter sp., indole-positive Proteus, Pseudomonas sp., and Serratia sp. were resistant to cefaclor.

Bacteria↗
PubMed1977

In vitro studies with cefaclor, a new oral cephalosporin.

In vitro studies were performed to evaluate the activity of cefaclor in comparison with cephalexin against 180 clinical isolates. Broth dilution susceptibility tests showed cefaclor to be 4- to 16-fold more active than cephalexin against Streptococcus pneumoniae, Haemophilus influenzae, and cephalothin-susceptible Enterobacteriaceae. Neither drug was highly active against cephalothin-resistant Enterobacteriaceae or methicillin-resistant Staphylococcus aureus. Cefaclor zones with 30-mug disks were generally larger than cephalexin zones, 4 mm larger than cephalothin zones against Enterobacteriaceae, and 6 mm smaller than cephalothin zones against S. aureus. Quantitative kill curves indicated that killing by both cefaclor and cephalexin was slow and often incomplete over a 24-h period. Cefaclor-induced filamentation of gram-negative bacilli was not as extensive as that produced by cephalexin, and some spherule formation did occur. However, cefaclor was significantly more unstable in solution than cephalexin, with a half-life of less than 6 h at 37 degrees C. Thus, results obtained in tests after prolonged incubation may not provide an accurate measure of cefaclor's activity.

Bacteria↗
PubMed1979

[Subinhibitory activity of cefaclor and cephalexin (author's transl)].

The determination of the minimal inhibitory concentration (MIC), which is usually performed after 18 to 24 hours of incubation, results in the case of cefaclor in a false picture of the actual activity. Cefaclor is chemically so unstable that after 24 hours only 2-5% of the substance is microbiologically active. In order to compare the activity of cefaclor and cephalexin, the effect of subinhibitory concentrations of both antibiotics against Escherichia coli and Klebsiella pneumoniae strains was studied by means of turbidimetry. After eight hours the absolute inhibitory concentration of cefaclor was lower than that of cephalexin with both methods. At the same time the effect of subinhibitory concentrations of both antibiotics was equal. Automatic measurement over 20 hours showed at the end of the experiment a higher MIC, and also a higher subinhibitory range, for cefaclor than for cephalexin. In our opinion the absolute inhibitory concentration after eight hours should be the criterion used to evaluate the effectiveness of cefaclor and cephalexin, and not the MIC which is usually used. The eight-hour criterion should also be applied in clinical use.

Cefaclor↗
PubMed1979

[Thin layer and high pressure liquid chromatography investigations with cefaclor in urine and serum (author's transl)].

After oral administration of 500 mg cefaclor, antibacterially active metabolites could not be detected in human urine using thin layer chromatography followed by bioautography. Degradation products of cefaclor could also not be detected in the serum of human volunteers (n = 10) using high pressure liquid chromatography with a reversed phase system. Cefaclor was eluated as a single and homogenous peak with a retention period of 2.9 min. High pressure liquid chromatography for the measurement of cefaclor serum levels and a technique for preparation of serum samples are described. After administration of 500 mg cefaclor to volunteers (n = 10), the average peak serum concentration of 9.8 mg/l, determined by high pressure liquid chromatography, was observed after one hour. Four hours later the serum level was 0.3 mg/l. Using microbiological methods no statistically significant difference was obtained in comparison with the chromatography results. Some of the sera stored at -75 degrees C for four weeks showed a substantial loss of activity of cefaclor.

Administration, Oral↗
PubMed1992

Cefaclor uptake by the proton-dependent dipeptide transport carrier of human intestinal Caco-2 cells and comparison to cephalexin uptake.

The human Caco-2 cell line spontaneously differentiates in culture to epithelial cells possessing intestinal enterocytic-like properties. These cells possess a proton-dependent dipeptide transport carrier that mediates the uptake of the cephalosporin antibiotic cephalexin (Dantzig, A.H. and Bergin, L. (1990) Biochim. Biophys. Acta 1027, 211-217). In the present study, the uptake of cefaclor was examined and found to be sodium-independent, proton-dependent, and energy-dependent. The initial rate of D-[3-phenyl-3H]cefaclor uptake was measured over a wide concentration range; uptake was mediated by a single saturable transport carrier with a Km of 7.6 mM and a Vmax of 7.6 nmol/min per mg protein and by a non-saturable component. Uptake was inhibited by dipeptides but not amino acids. The carrier showed a preference for the L-isomer. The effect of the presence of a 5-fold excess of other beta-lactam antibiotics was examined on the initial rates of 1 mM cefaclor and 1 mM cephalexin uptake. Uptake rates were inhibited by the orally absorbed antibiotics, cefadroxil, cefaclor, loracarbef, and cephradine and less so by the parenteral agents tested. The initial uptake rates of both D-[9-14C]cephalexin and D-[3-phenyl-3H]cefaclor were competitively inhibited by cephalexin, cefaclor, and loracarbef with Ki values of 9.2-13.2, 10.7-6.2, and 7.7-6.4 mM, respectively. Taken together, these data suggest that a single proton-dependent dipeptide transport carrier mediates the uptake of these orally absorbed antibiotics into Caco-2 cells, and provide further support for the use of Caco-2 cells as a cellular model for the study of the intestinal proton-dependent dipeptide transporter.

2,4-Dinitrophenol↗
PubMed1979

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

Cefaclor or amoxicillin was given to 51 randomly assigned patients with urinary tract infections. Inclusion in the study required two pretreatment urine cultures yielding the same organism (susceptible to both antibiotics) in concentrations greater than or equal to 10(5)/ml. Both drugs were administered as 250 mg. orally every eight hours for ten days. Cefaclor was given to 27 patients and amoxicillin to 24. Most patients in both groups had negative urine cultures at five to nine days and four to six weeks following therapy. One patient in each group was unsuccessfully treated. Relapse or reinfection occurred with similar frequency in both treatment groups. Both antibiotics were well tolerated. minimal inhibiting concentrations (MICS) of cefaclor, amoxicillin, cephradine, and cephalexin were determined by an agar dilution technique for the 44 available pretreatment isolates (41 Escherichia coli and 3 Proteus mirabilis). Mean MICs (micrograms./ml., +/- SD) were 2.2 +/- 1.4 for cefaclor, 4.4 +/- 2.0 with amoxicillin, 8.1 +/- 4.2 for cephradine, and 5.7 +/- 3.0 with cephalexin. Cefaclor is highly active in vitro against those gram-negative bacteria which are commonly isolated from urine. Cefaclor is as effective as amoxicillin when administered three times daily for the treatment of urinary tract infection.

Amoxicillin↗
PubMedDate not supplied

Randomized comparative study of ceftibuten versus cefaclor in the treatment of acute lower respiratory tract infections.

In a randomized, single-blind trial, ceftibuten in doses of 200 mg and 300 mg administered b.i.d., was compared with cefaclor 500 mg t.i.d. in acute lower respiratory tract infections. A total 545 patients were enrolled, of which 263 were evaluable for efficacy. All patients were adults with a diagnosis of either bacterial pneumonia or bronchitis. The infective organism was eliminated in 83% of the patients in the ceftibuten 200-mg b.i.d. treatment group and in 85% of patients in the 300-mg b.i.d. treatment group. The organisms were eliminated in 79% of cefaclor-treated patients. Satisfactory clinical responses were obtained in 91% of patients in the ceftibuten 200-mg b.i.d. treatment group and in 92% of patients in the ceftibuten 300-mg b.i.d. group. Satisfactory clinical responses were obtained in 91% of cefaclor-treated patients. Predominant pathogens isolated were Streptococcus pneumoniae, Haemophilus influenzae, Moraxella (Branhamella) catarrhalis, and strains of Enterobacteriaceae. Adverse experiences reported were similar for the ceftibuten and cefaclor treatment groups. Gastrointestinal side effects occurred in 6% of patients treated with ceftibuten 200 mg BID, 9% in those treated with 300 mg BID, and 7% of cefaclor-treated patients. Ceftibuten 200 and 300 mg twice daily was as effective as cefaclor bacteriologically and clinically in the treatment of lower respiratory tract infections.

Acute Disease↗
PubMed1986

A randomized controlled trial of amoxicillin plus clavulanate compared with cefaclor for treatment of acute otitis media.

We performed a randomized controlled trial of amoxicillin plus clavulanate versus cefaclor for treatment of acute otitis media. Total daily doses given in three divided doses were 40 mg/kg amoxicillin plus 10 mg/kg clavulanate, and 40 mg/kg cefaclor. Pathogens were eradicated from the middle ear exudate after 3 to 6 days of therapy in 35 (97%) of 36 patients given amoxicillin-clavulanate compared with 24 (75%) of 32 given cefaclor (P = 0.028). When analysis was restricted to patients with positive urine or serum drug assays during therapy, pathogens were eliminated in 33 (97%) of 34 patients given amoxicillin-clavulanate compared with 21 (75%) of 28 given cefaclor (P = 0.026). Bacterial isolates associated with bacteriologic failure of cefaclor therapy were Streptococcus pneumoniae (two patients), beta-lactamase-negative Haemophilus influenzae (four), and beta-lactamase-positive Branhamella catarrhalis (two). The single failure with amoxicillin-clavulanate therapy was associated with non-beta-lactamase-producing H. influenzae isolated from the middle ear exudate. We conclude that cefaclor is less efficacious than amoxicillin-clavulanate for the treatment of acute otitis media.

Acute Disease↗
PubMed2001

Penetration of cefaclor into the interstitial space fluid of skeletal muscle and lung tissue in rats.

PURPOSE: To measure and compare the penetration of cefaclor from the plasma compartment into the interstitial space of lung and skeletal muscle in rats and to integrate the data in a pharmacokinetic model. METHODS: Unbound interstitial concentrations in muscle and lung were measured by in vivo microdialysis following i.v. bolus doses of 50 and 75 mg/kg cefaclor. Unbound muscle concentrations were also measured after a primed, continuous i.v. infusion at an infusion rate of 0.3 mg/kg/min. RESULTS: The cefaclor half-life in plasma, muscle and lung was approximately 1 h. Unbound cefaclor concentrations in muscle and lung were found to be virtually identical. A 2-compartment body model was fitted to the data with a tissue penetration factor (AUC(tissue(unbound)))/AUC(plasma(unbound))) of approximately 0.26 independent of dose, tissue and mode of administration. CONCLUSIONS: Unbound concentrations of cefaclor in the interstitial space fluid of lung and skeletal muscle are of similar magnitude and lower than those in plasma. Using total plasma concentrations would overestimate the antibacterial activity of the drug and therefore its clinical efficacy. Instead, therapeutically active levels of cefaclor at the site of action should be taken into account. Microdialysis allows direct measurement of these unbound concentrations.

Algorithms↗