Influence of an antacid containing aluminum and magnesium on the pharmacokinetics of cefixime.
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Interaction studies in dogs have indicated that antacids significantly decrease the oral bioavailability of cefixime. Twelve healthy adult male volunteers participated in a randomized, four-way crossover trial to evaluate the influence of an aluminum-magnesium antacid (Maalox; 20 ml) on the pharmacokinetics of cefixime (400 mg). Regimens were (i) cefixime alone; (ii) cefixime simultaneous with antacid; (iii) cefixime 2 h before antacid; and (iv) cefixime 2 h after antacid. Serial blood and urine samples were collected over a 24-h period following each dose of cefixime. There was a 1-week washout interval between regimens. Cefixime concentrations in serum and urine were analyzed by high-performance liquid chromatography. Maximum cefixime concentrations in serum for regimens i through iv were (mean +/- standard deviation) 4.9 +/- 1.4, 5.7 +/- 1.3, 5.1 +/- 1.0, and 5.5 +/- 1.5 micrograms/ml, respectively. Corresponding values for area under the serum concentration-time curve extrapolated to infinity were 38.3 +/- 14.5, 42.8 +/- 13.9, 38.5 +/- 9.8, and 41.6 +/- 16.7 micrograms.h/ml. There was a trend toward increased concentrations in serum and area under the curve of cefixime when it was administered concomitantly with antacid; however, these differences were not statistically significant (P greater than 0.05; analysis of variance). We conclude that single-dose administration of an aluminum-magnesium antacid does not significantly decrease the oral bioavailability of cefixime. (+info)
In vitro activities of selected new and long-acting cephalosporins against Pasteurella multocida.
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The activities of six agents commonly used in treating infections of the skin and soft tissues and the action of selected cephalosporins against 15 isolates of Pasteurella multocida were assessed by a macro-broth dilution method. Broad-spectrum cephalosporins, including ceftriaxone and cefixime, had excellent in vitro activities (MIC less than or equal to 0.098) against the isolates tested. (+info)
In vitro activity of difloxacin hydrochloride (A-56619), A-56620, and cefixime (CL 284,635; FK 027) against selected genital pathogens.
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Management of sexually transmitted diseases is facilitated by having antimicrobial agents with activity against all of the major genital pathogens. Newer quinolones show promise of being active against Neisseria gonorrhoeae and Chlamydia trachomatis. Two quinolones, difloxacin (A-56619) and A-56620, and an oral cephalosporin, cefixime (CL 284,635; FK 027), were evaluated in vitro. All three were highly active against 400 isolates of N. gonorrhoeae, including penicillinase-producing N. gonorrhoeae, N. gonorrhoeae with chromosomally mediated resistance, and isolates with penicillin MICs of less than 1 microgram/ml. Susceptibilities to one antimicrobial agent were usually strongly correlated with susceptibilities to the other antimicrobial agents evaluated, but isolates with increasing resistance to beta-lactams were least likely to show increasing resistance to quinolones. Difloxacin and, to a lesser extent, A-56620 were active against all 10 strains of C. trachomatis, and both had moderate activity against over 200 strains of Gardnerella vaginalis. Based on in vitro activity, difloxacin and A-56620 merit in vivo assessment for management of both C. trachomatis and N. gonorrhoeae infections, and cefixime shows considerable promise for treatment of N. gonorrhoeae infections. (+info)
Antibacterial activities of cefpodoxime, cefixime, and ceftriaxone.
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Cefpodoxime, cefixime, and ceftriaxone inhibited Branhamella catarrhalis at less than or equal to 1 microgram/ml, beta-hemolytic streptococci at less than or equal to 0.25 microgram/ml, Neisseria meningitidis at less than or equal to 0.06 microgram/ml, and Haemophilus influenzae (other than beta-lactamase-negative, ampicillin-resistant isolates) at less than or equal to 0.12 microgram/ml. The MICs for 50% of isolates of the family Enterobacteriaceae other than Citrobacter freundii, Enterobacter aerogenes, and Enterobacter cloacae were less than or equal to 1 microgram/ml for all three cephalosporins. The MICs of each cephalosporin for 90% of staphylococci, enterococci, and Pseudomonas aeruginosa isolates were greater than 16 micrograms/ml. Inoculum effects were noted with cefpodoxime and cefixime with beta-lactamase-positive H. influenzae. (+info)
In vitro activity of an oral iminomethoxy aminothiazolyl cephalosporin, R-3746.
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The in vitro activity of R-3746, an iminomethoxy aminothiazolyl cephalosporin with a CH2OCH3 moiety at position 3, was compared with those of other antibiotics. R-3746 inhibited the majority of hemolytic streptococci (groups A, B, C, F, and G) and Streptococcus pneumoniae at less than 0.06 micrograms/ml, which was comparable to the activity of amoxicillin, 2- to 8-fold more active than cefixime, and 16- to 64-fold more active than cefaclor and cephalexin. Ninety percent of beta-lactamase-producing Haemophilus influenzae and Neisseria gonorrhoeae were inhibited at a concentration 0.25 micrograms/ml, but it was less active against Branhamella spp. It did not inhibit (MIC, greater than 16 micrograms/ml) enterococci, viridans group streptococci, or methicillin-resistant staphylococci. The MICs of R-3746 for 90% of strains tested for Escherichia coli; Klebsiella pneumoniae; Citrobacter diversus; Proteus mirabilis; and Salmonella, Shigella, and Yersinia spp. were less than or equal to 1 micrograms/ml. It was two- to eightfold less active than cefixime but was markedly superior to cefaclor, cephalexin, amoxicillin-clavulanate, and trimethoprimsulfamethoxazole. R-3746 inhibited 50% of Enterobacter cloacae, Enterobacter aerogenes, Citrobacter freundii, Morganella spp., Providencia spp., Proteus vulgaris, and Serratia marcescens at less than or equal to 8 micrograms/ml. Pseudomonas spp. were resistant. Fifty percent of Clostridium spp. were inhibited by 0.5 micrograms/ml, but MICs for Bacteroides spp. were greater than 128 micrograms/ml. R-3746 was not appreciably hydrolyzed by most chromosomal and plasmid-mediated beta-lactamases. (+info)
In vitro susceptibility of Haemophilus influenzae to cefixime.
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The in vitro activity of cefixime against 2,458 clinical isolates of Haemophilus influenzae was determined. All the strains were inhibited by less than or equal to 2 micrograms of cefixime per ml, and the modal MIC was 0.03 micrograms/ml. Activity was unaffected by the presence of beta-lactamase produced by 157 isolates. Nineteen of the twenty-four isolates for which cefixime MICs were greater than or equal to 0.5 micrograms/ml were beta-lactamase negative but showed reduced susceptibility to ampicillin. (+info)
Penetration of cefixime into fibrin clots and in vivo efficacy against Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus.
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The experimental model of infected fibrin clots in rabbits was used to study the penetration and in vivo activity of cefixime against Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. The respective MICs of cefixime against these strains were 0.25, 2, and 8 micrograms/ml. The clots were infected with 10(6) to 10(8) CFU/g. Groups of four animals for each strain received an intravenous injection of 100 mg of cefixime per kg over 30 min. High peak levels were observed in serum (146.5 micrograms/ml) and clots (15.8 micrograms/g), and the antibiotic was still detectable in the clots (0.6 micrograms/g) 24 h after administration. The respective serum and clot elimination half-lives were 0.7 and 5.0 h. The mean serum protein binding was 23.8 +/- 3.8%. Cefixime was highly bactericidal against K. pneumoniae and E. coli and reduced, over a 24-h period, their respective colony counts by 7.8 log10 and 6.2 log10 CFU/g of fibrin. It was less effective against S. aureus but still reduced the bacterial counts by 2.8 log10 CFU/g of fibrin. The present results demonstrate that cefixime, a new broad-spectrum oral cephalosporin, has a long tissue half-life which ensured, at the dose given here, good in vivo bactericidal activity against both gram-positive and gram-negative bacteria up to 24 h after administration of the antibiotic. (+info)
Bowel flora changes in humans receiving cefixime (CL 284,635) or cefaclor.
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Twelve healthy young male subjects received either cefixime, a new oral cephalosporin (CL 284,635), or cefaclor (six subjects on each drug) orally for 2 weeks. In the case of cefixime, single daily doses of 400 mg were taken; with cefaclor, the dosage was 250 mg three times daily. Modest changes in the fecal flora were noted in both drug groups, but the changes were of different types. In the case of cefixime, there was more of an impact on the indigenous flora, and in the case of cefaclor, there was more ingrowth of new flora. With cefixime, Enterobacteriaceae were usually decreased (the decrease in Escherichia coli count was statistically significant), as were counts of clostridia and sometimes Bifidobacterium spp.; the Bacteroides fragilis group was eliminated in one subject. Coincident with these decreases, four subjects had increases in counts of group D streptococci of 3 logs or more. There was new appearance of Clostridium difficile in four subjects and of Staphylococcus aureus in one; four new strains of Enterobacteriaceae appeared. With cefaclor, there was no decrease of E. coli counts; two subjects had elimination of Bifidobacterium spp. There was little change in counts of group D streptococci. On the other hand, there were 13 new strains of Enterobacteriaceae, two of S. aureus, and three of C. difficile. (+info)