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PubMed1992

Susceptibilities of 540 anaerobic gram-negative bacilli to amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin.

Agar dilution MIC testing of amoxicillin, amoxicillin-BRL 42715, amoxicillin-clavulanate, temafloxacin, and clindamycin against 496 beta-lactamase-producing anaerobic gram-negative rods revealed MICs for 90% of the strains tested of 256.0 (amoxicillin), 2.0 (amoxicillin-BRL 42715 and amoxicillin-clavulanate), and 4.0 (temafloxacin and clindamycin) microgram/ml. Amoxicillin, temafloxacin, and clindamycin inhibited all 44 beta-lactamase-negative strains (MICs for 90% of the strains tested, less than or equal to 2.0 micrograms/ml). BRL 42715 will not be developed, but temafloxacin merits clinical evaluation.

Amoxicillin↗
PubMed1989

Amoxicillin in the treatment of asymptomatic bacteriuria in pregnancy: a single dose of 3 g amoxicillin versus a 4-day course of 3 doses 750 mg amoxicillin.

A prospective, randomized, controlled comparative clinical trial was carried out with the aim of investigating the efficacy and tolerance of two different dosage regimens of amoxicillin in the treatment of asymptomatic bacteriuria during pregnancy. Patients in group A received a single dose of 3 g amoxicillin, which was compared to a 4-day course of 3 X 750 mg amoxicillin tablets taken every 8 h (group B). Significant bacteriuria (CFU greater than or equal to 10(5)/ml clean catch midstream urine and CFU greater than or equal to 10(4)/ml urine obtained by bladder catheterization) was diagnosed using the dip-slide method (Uricult). 91 pregnant women with a mean gestational age of 25 weeks (14-38) were randomly allocated to the two treatment groups. 53 patients were assigned to group A and 38 patients to group B. The treatment groups were comparable in terms of age and duration of pregnancy. Urine culture tests were performed 1 and 4 weeks after completion of therapy. The predominant species was Escherichia coli, which was isolated in 60-65% of the cases. Bacteriological cure rates at 1 and 4 weeks, respectively, were 77 and 74% in group A, and 62 and 62% in group B. These differences were statistically not significant. The incidence of side effects was 4% in group A and 13% in group B. The results obtained in the present study suggest that in the treatment of asymptomatic bacteriuria in pregnancy, a single dose of 3 g amoxicillin is as effective and acceptable as a 4-day course. In addition, the single-dose regimen offers the advantage of a reduction in total dose, lower costs and better patient compliance.

Adolescent↗
PubMed1983

[Blood amoxicillin concentrations in agricultural animals and poultry treated intramuscularly with drug forms containing amoxicillin sodium and amoxicillin trihydrate].

The sodium salts of ampicillin and amoxicillin at the single i/m application in 20 per cent water solutions at the rate of 10 mg per kg of body mass guaranteed close therapeutic concentrations of both antibiotics in the blood serum of birds and rabbits. Amoxicillin-trihydrate in a 20% water suspension applied i/m in a single dose of 10 mg/kg persisted in a therapeutic concentrations in the blood serum of birds for a longer time (10 hours) than ampicillin-trihydrate (8 hours). The oil suspension containing 20% amoxicillin-trihydrate guaranteed bacteriostatic serum concentrations in the course of 24 to 48 hours at single i/m application in doses of 20 and 30 mg/kg, depending on the amount and the species of animal. The optimal doses for calves and sheep were 20 mg/kg and 30 mg/kg injected at intervals of 24, resp., 48 hours, and for pigs and birds it were 30 mg/kg at 24-hour intervals. The choice of one or another dose depended on the sensitivity of the disease agents.

Amoxicillin↗
PubMed1998

In vivo activities of amoxicillin and amoxicillin-clavulanate against Streptococcus pneumoniae: application to breakpoint determinations.

The in vivo activities of amoxicillin and amoxicillin-clavulanate against 17 strains of Streptococcus pneumoniae with penicillin MICs of 0.12-8.0 mg/liter were assessed in a cyclophosphamide-induced neutropenic murine thigh infection model. Renal impairment was produced by administration of uranyl nitrate to prolong the amoxicillin half-life in the mice from 21 to 65 min, simulating human pharmacokinetics. Two hours after thigh infection with 10(5) to 10(6) CFU, groups of mice were treated with 7 mg of amoxicillin per kg of body weight alone or combined with clavulanate (ratio, 4:1) every 8 h for 1 and 4 days. There was an excellent correlation between the MIC of amoxicillin (0.03 to 5.6 mg/liter) and (i) the change in log10 CFU/thigh at 24 h and (ii) survival after 4 days of therapy. Organisms for which MICs were 2 mg/liter or less were killed at 1.4 to 4.2 and 1.6 to 4.1 log10 CFU/thigh at 24 h by amoxicillin and amoxicillin-clavulanate, respectively. The four strains for which MICs were >4 mg/liter grew 0.2 to 2.6 and 0.6 to 2. 3 logs at 24 h despite therapy with amoxicillin and amoxicillin-clavulanate, respectively. Infection was uniformly fatal by 72 h in untreated mice. Amoxicillin therapy resulted in no mortality with organisms for which MICs were 1 mg/liter or less, 20 to 40% mortality with organisms for which MICs were 2 mg/liter, and 80 to 100% mortality with organisms for which MICs were 4.0-5.6 mg/liter. Lower and higher doses (0.5, 2, and 20 mg/kg) of amoxicillin were studied against organisms for which MICs were near the breakpoint. These studies demonstrate that a reduction of 1 log10 or greater in CFU/thigh at 24 h is consistently observed when amoxicillin levels exceed the MIC for 25 to 30% of the dosing interval. These studies would support amoxicillin (and amoxicillin-clavulanate) MIC breakpoints of 1 mg/liter for susceptible, 2 mg/liter for intermediate, and 4 mg/liter for resistant strains of S. pneumoniae.

Amoxicillin↗
PubMed1995

[Amoxicillin and clavulanic acid versus amoxicillin plus gentamicin in the empirical initial treatment of urinary tract infections in hospitalized patients].

We compared the fixed combination amoxicillin plus clavulanic acid with that of amoxicillin plus gentamicin in the empirical initial treatment of severe urinary tract infections. The study included 87 hospitalized patients (51 women and 36 men, mean age 58 +/- 22 years) with acute uncomplicated pyelonephritis (n = 48) or with complicated urinary tract infections (n = 39). 80 patients (92%) had fever and 31 patients (36%) positive blood cultures. 45 patients were randomly assigned to amoxicillin plus clavulanic acid and 42 to amoxicillin plus gentamicin. Overall, 18 patients (21%) were infected with organisms resistant in vitro to amoxicillin plus clavulanic acid, whereas no pathogen was isolated with resistance to amoxicillin plus gentamicin (p < 0.0001). At the end of the empirical treatment (4.2 +/- 1.5 days after the start), significant bacteriuria was present in 6/39 patients (15%) assigned to amoxicillin plus clavulanic acid, compared to 0/34 patients assigned to amoxicillin plus gentamicin (p < 0.05). The clinical response was satisfactory in both groups, and the time from start of therapy to resolution of fever was 2.2 +/- 1.4 days in the amoxicillin plus clavulanic acid group and 2.3 +/- 1.7 days in the amoxicillin plus gentamicin group. Although the in-vitro resistance did not result in a lower clinical efficacy of amoxicillin plus clavulanic acid compared to amoxicillin plus gentamicin in our relatively small sample of patients, the data indicate that the antimicrobial activity of amoxicillin plus clavulanic acid is inadequate to cover the spectrum of causative agents in hospitalized patients with pyelonephritis or complicated urinary tract infections. Amoxicillin plus clavulanic acid should therefore not be used in the initial empirical treatment of these infections.

Adult↗
PubMedDate not supplied

Efficacy of empirically prescribed amoxicillin and amoxicillin + clavulanic acid in children's reactive arthritis: a randomised trial.

OBJECTIVE: To evaluate the efficacy of early empiric prescription of amoxicillin and amoxicillin + clavulanic acid in children with reactive arthritis (ReA) when the arthritis-triggering microorganism is not identified. METHODS: 138 children, ranging in age from 2 to 16 years, with ReA of up to 3 months duration were randomly assigned to 3 groups and either prescribed antibacterial treatment with amoxicillin or amoxicillin + clavulanic acid (amoxicillin-potassium clavulanate combination) or were not given antibiotics (control group). Patients in all 3 groups were prescribed the usual treatment with nonsteroidal antiinflammatory drugs. Both groups of patients under antibacterial treatment were randomised into 2 subgroups: patients given a 10- to 14-day or a 28-day-duration antibacterial course. The results of the study were evaluated after 1 and 3 months of observation by determining the percentage of patients that had no clinical or laboratory signs of disease activity. RESULTS: After 1 month of observation no signs of disease activity were found in 48.0% of patients who were prescribed amoxicillin, in 58.5% of patients treated with amoxicillin + clavulanic acid, and only in 13.0% of patients from the control group (p < 0.001 for either antibacterial treatment in comparison with the control group). After 3 months of observation no disease activity was found in 92.0% of patients who used amoxicillin, in 95.1% of those treated with amoxicillin + clavulanic acid, and in 58.7% of children from the control group (p < 0.001 for either antibacterial treatment in comparison with the control group). There was no significant difference in the efficacy of amoxicillin and amoxicillin + clavulanic acid. The duration of the antibacterial course showed no influence on the results of treatment. CONCLUSION: Amoxicillin or amoxicillin + clavulanic acid in 10- to 14-day courses are advisable, in addition to the antirheumatic treatment, for children in the early stage of ReA when the arthritis-triggering microorganism is not identified.

Adolescent↗
PubMed2005

Efficacy and safety of pharmacokinetically enhanced amoxicillin-clavulanate at 2,000/125 milligrams twice daily for 5 days versus amoxicillin-clavulanate at 875/125 milligrams twice daily for 7 days in the treatment of acute exacerbations of chronic bronchitis.

This randomized, controlled trial was designed to show that a short, 5-day course of pharmacokinetically enhanced amoxicillin-clavulanate at 2,000/125 mg (Augmentin XR) is as effective clinically as a longer, 7-day course of conventional amoxicillin-clavulanate at 875/125 mg (both given twice daily) in the treatment of acute exacerbations of chronic bronchitis (AECB). Amoxicillin-clavulanate at 2,000/125 mg was designed to extend the therapeutic levels of amoxicillin in serum over the 12-h dosing interval, compared with conventional formulations, to eradicate bacterial strains for which amoxicillin MICs were < or =4 microg/ml while retaining efficacy against beta-lactamase-producing pathogens. A total of 893 patients were randomized and received study medication (amoxicillin-clavulanate at 2,000/125 mg for 443 patients and 875/125 mg for 450 patients). Overall, 141 patients receiving amoxicillin-clavulanate at 2,000/125 mg and 135 receiving the comparator formulation had at least one pathogen identified at screening. Amoxicillin-clavulanate at 2,000/125 mg was as effective clinically in the per-protocol (PP) population at the test of cure (days 14 to 21, primary efficacy endpoint) as amoxicillin-clavulanate at 875/125 mg (clinical success rates of 93.0 and 91.2%, respectively; treatment difference, 1.8; 95% confidence interval [CI], -2.2, 5.7). Bacteriological success in the bacteriology PP population was high for both formulations (amoxicillin-clavulanate at 2,000/125 mg, 76.7%; amoxicillin-clavulanate at 875/125 mg, 73.0%; treatment difference, 3.8; 95% CI, -7.5, 15.0). Both therapies were well tolerated, with a similar incidence of adverse events. Fewer than 5% of patients in each group withdrew from the study due to adverse events. The shorter, 5-day course of amoxicillin-clavulanate at 2,000/125 mg was shown to be as effective clinically as a longer, 7-day course of amoxicillin-clavulanate at 875/125 mg, with high bacteriological efficacy and no difference in tolerability.

Acute Disease↗
PubMed1987

Response of Streptococcus pyogenes to therapy with amoxicillin or amoxicillin-clavulanic acid in a mouse model of mixed infection caused by Staphylococcus aureus and Streptococcus pyogenes.

The response of Streptococcus pyogenes to amoxicillin or amoxicillin-clavulanic acid (Augmentin; Beecham Group) therapy of a mixed streptococcal-staphylococcal infection was studied in a surgical wound in mice. A superficial wound was produced on the backs of anesthetized mice, and a suture infected with S. pyogenes, Staphylococcus aureus, or a mixed inoculum of both organisms was inserted. Oral therapy was started 4 h after infection and continued for 3 days. Both amoxicillin and amoxicillin-clavulanic acid were effective in eliminating the streptococci from the pure wound infection. In contrast, amoxicillin failed to eliminate the streptococci from a mixed infection in which a beta-lactamase-producing strain of S. aureus was also present, wound counts reaching 10(7) streptococci per wound by 80 h, whereas amoxicillin-clavulanic acid reduced the count to less than 33 streptococci per wound by 24 h. Numbers of S. aureus were also reduced by amoxicillin-clavulanic acid therapy, controlling the infection, whereas amoxicillin was ineffective. Also of significance was the fact that successful therapy was achieved with blood and tissue concentrations of amoxicillin and clavulanic acid of the same order as those measured in humans. These results show that amoxicillin therapy failed to eliminate S. pyogenes from a wound infection in the presence of a beta-lactamase-producing strain of S. aureus and suggest the potential of amoxicillin-clavulanic acid in the treatment of mixed bacterial skin infections involving beta-lactamase-producing organisms.

Amoxicillin↗
PubMed1988

A comparative study of amoxicillin-clavulanate and amoxicillin. Treatment of otitis media with effusion.

A double-blind randomized clinical trial was conducted at two sites comparing amoxicillin-clavulanate potassium (Augmentin) and amoxicillin trihydrate for the treatment of otitis media with effusion ("secretory otitis media"). One hundred eight subjects were randomly assigned to receive a ten-day course of either drug regimen. Clinical response was assessed at ten days and four weeks after entry. For those without middle ear effusion at four weeks, recurrence rates were measured at 8, 12, and 16 weeks after entry. At ten days following entry, 29 (51.8%) of 56 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 16 (32.0%) of 50 subjects in the amoxicillin-treated group (P = .06). At four weeks following entry, 26 (50.0%) of 50 subjects in the amoxicillin-clavulanate-treated group were effusion free compared with 23 (51.1%) of 45 subjects in the group given amoxicillin. By the 16-week visit, eight (36.4%) of 22 subjects in the amoxicillin-clavulanate-treated group who were effusion free at four weeks had recurrence of effusion, compared with 12 (63.2%) of 19 subjects in the amoxicillin-treated group. This study suggests that there was a favorable clinical response immediately following treatment in the amoxicillin-clavulanate--treated subjects as compared with those treated with amoxicillin, but this benefit was not sustained at the four-week end point.

Adolescent↗
PubMed2004

Double-blind, randomized study of the efficacy and safety of oral pharmacokinetically enhanced amoxicillin-clavulanate (2,000/125 milligrams) versus those of amoxicillin-clavulanate (875/125 milligrams), both given twice daily for 7 days, in treatment of bacterial community-acquired pneumonia in adults.

This randomized, double-blind, noninferiority trial was designed to demonstrate that pharmacokinetically enhanced amoxicillin-clavulanate (2,000/125 mg) was at least as effective clinically as amoxicillin-clavulanate 875/125 mg, both given twice daily for 7 days, in the treatment of community-acquired pneumonia in adults. In total, 633 clinically and radiologically confirmed community-acquired pneumonia patients (intent-to-treat population) were randomized to receive either oral amoxicillin-clavulanate 2,000/125 mg (n = 322) or oral amoxicillin-clavulanate 875/125 mg (n = 311). At screening, 160 of 633 (25.3%) patients had at least one typical pathogen isolated from expectorated or invasive sputum samples or blood culture (bacteriology intent-to-treat population). Streptococcus pneumoniae (58 of 160, 36.3%), methicillin-susceptible Staphylococcus aureus (34 of 160, 21.3%), and Haemophilus influenzae (33 of 160, 20.6%) were the most common typical causative pathogens isolated in both groups in the bacteriology intent-to-treat population. Clinical success in the clinical per protocol population at test of cure (days 16 to 37), the primary efficacy endpoint, was 90.3% (223 of 247) for amoxicillin-clavulanate 2,000/125 mg and 87.6% (198 of 226) for amoxicillin-clavulanate 875/125 mg (treatment difference, 2.7; 95% confidence interval, -3.0, 8.3). Bacteriological success at test of cure in the bacteriology per protocol population was 86.6% (58 of 67) for amoxicillin-clavulanate 2,000/125 mg and 78.4% (40 of 51) for amoxicillin-clavulanate 875/125 mg (treatment difference, 8.1%; 95% confidence interval, -5.8, 22.1). Both therapies were well tolerated. Amoxicillin-clavulanate 2,000/125 mg twice daily was shown to be as clinically effective as amoxicillin-clavulanate 875/125 mg twice daily for 7 days in the treatment of adult patients with community-acquired pneumonia, without a noted increase in the reported rate of adverse events.

Adolescent↗
PubMed2005

Comparative bacteriological efficacy of pharmacokinetically enhanced amoxicillin-clavulanate against Streptococcus pneumoniae with elevated amoxicillin MICs and Haemophilus influenzae.

A new pharmacokinetically enhanced formulation of amoxicillin-clavulanate (2,000 mg of amoxicillin/125 mg of clavulanate twice a day; ratio 16:1) has been designed, with sustained-release technology, to allow coverage of bacterial strains with amoxicillin-clavulanic acid MICs of at least 4/2 mug/ml. The bacteriological efficacy of amoxicillin-clavulanate, 2,000/125 mg twice a day, ratio 16:1, was compared in a rat model of respiratory tract infection versus four other amoxicillin-clavulanate formulations: 8:1 three times a day (1,000/125 mg), 7:1 three times a day (875/125 mg), 7:1 twice a day (875/125 mg), and 4:1 three times a day (500/125 mg); levofloxacin (500 mg once a day); and azithromycin (1,000 mg on day 1 followed thereafter by 500 mg once a day). Bacterial strains included Streptococcus pneumoniae, with amoxicillin-clavulanic acid MICs of 2/1 (one strain), 4/2, or 8/4 microg/ml (three strains each), and Haemophilus influenzae, one beta-lactamase-positive strain and one beta-lactamase-negative, ampicillin-resistant strain. Animals were infected by intrabronchial instillation. Antibacterial treatment commenced 24 h postinfection, with doses delivered by computer-controlled intravenous infusion to approximate the concentrations achieved in human plasma following oral administration. Plasma concentrations in the rat corresponded closely with target human concentrations for all antimicrobials tested. Amoxicillin-clavulanate, 2,000/125 mg twice a day, ratio 16:1, was effective against all S. pneumoniae strains tested, including those with amoxicillin-clavulanic acid MICs of up to 8/4 microg/ml and against beta-lactamase-producing and beta-lactamase-negative ampicillin-resistant H. influenzae. These results demonstrate the bacteriological efficacy of pharmacokinetically enhanced amoxicillin-clavulanate 2,000/125 mg twice a day (ratio 16:1) against S. pneumoniae with amoxicillin-clavulanic acid MICs of at least 4/2 microg/ml and support clavulanate 125 mg twice a day as sufficient to protect against beta-lactamase in this rat model.

Amoxicillin↗
PubMed1986

Comparative effectiveness of amoxicillin and amoxicillin-clavulanate potassium in acute paranasal sinus infections in children: a double-blind, placebo-controlled trial.

This study compared the relative effectiveness of two antimicrobial preparations, amoxicillin and amoxicillin-clavulanate potassium (Augmentin), in the treatment of acute maxillary sinusitis in children 2 to 16 years of age. Of 171 children with persistent (ten to 30 days' duration) nasal discharge or daytime cough or both, 136 (80%) had abnormal maxillary sinus radiographs. These children were stratified by age and severity of symptoms and randomly assigned to receive either amoxicillin, amoxicillin-clavulanate potassium, or placebo. After the exclusion of 28 children with throat cultures positive for group A Streptococcus and 15 who did not complete their medication, the remaining 93 children were evaluated: 30 received amoxicillin, 28 received amoxicillin-clavulanate potassium, and 35 received placebo. Clinical assessment was performed at three and ten days. On each occasion, children treated with an antibiotic were more likely to be cured than children receiving placebo (P less than .01 at three days, P less than .05 at ten days). The overall cure rate was 67% for amoxicillin, 64% for amoxicillin-clavulanate potassium, and 43% for placebo.

Acute Disease↗
PubMed1990

Beta-lactamase production and susceptibilities to amoxicillin, amoxicillin-clavulanate, ticarcillin, ticarcillin-clavulanate, cefoxitin, imipenem, and metronidazole of 320 non-Bacteroides fragilis Bacteroides isolates and 129 fusobacteria from 28 U.S. centers.

beta-Lactamase production (nitrocefin disk method) and agar dilution susceptibility of amoxicillin, amoxicillin-clavulanate, ticarcillin, ticarcillin-clavulanate, cefoxitin, imipenem, and metronidazole were determined for 320 Bacteroides species (not Bacteroides fragilis group) and 129 fusobacteria from 28 U.S. centers. Overall, 64.7% of Bacteroides species and 41.1% of fusobacteria were beta-lactamase positive. Among the Bacteroides species, positivity rates were highest for B. bivius (85.0%), followed by B. splanchnicus (83.3%), B. eggerthii (77.8%), and B. oralis (77.1%); 54.5% of black-pigmented Bacteroides species were beta-lactamase positive. Among the fusobacteria, Fusobacterium mortiferum showed the highest rate of beta-lactamase positivity (76.9%). MICs of amoxicillin (128 micrograms/ml) and ticarcillin (64 micrograms/ml) for 90% of all beta-lactamase-positive strains were reduced to 4 and 2 micrograms/ml, respectively, with the addition of clavulanate. MICs of amoxicillin and ticarcillin for 90% of all beta-lactamase-negative strains were 1 and 4 micrograms/ml, respectively, and greater than or equal to 98.4% of the strains were susceptible to the beta-lactams tested. Of the beta-lactamase-producing strains, 45.9% were susceptible to amoxicillin at less than or equal to 4 micrograms/ml and 93.4% were susceptible to ticarcillin at less than or equal to 64 micrograms/ml; the addition of clavulanate raised the rates to 90.4 and 100%, respectively. All strains were susceptible to cefoxitin, imipenem, and metronidazole. The activity of amoxicillin against 29 beta-lactamase-producing strains (10 Bacteroides species and 19 fusobacteria) was not enhanced by the addition of clavulanate; however, 82.7% of these strains were susceptible to amoxicillin, and all were susceptible to ticarcillin. Although beta-lactamase positivity is on the increase in non-B. fragilis group Bacteroides species and fusobacteria, amoxicillin-clavulanate, ticarcillin, cefoxitin, imipenem, and metronidazole should be suitable for the treatment of infections with these strains. The addition of clavulanate does not appreciably improve the efficacy of ticarcillin against these organisms.

Amoxicillin↗
PubMed1985

Comparison between penetration of amoxicillin combined with carbocysteine and amoxicillin alone in pathological bronchial secretions and pulmonary tissue.

Patients with chronic bronchitis were treated orally with either amoxicillin (500 mg) alone or in combination with carbocysteine (150 mg), thrice daily for five days, in order to assess whether the combination allows higher antibiotic levels to be obtained in bronchial mucus than those obtained from amoxicillin alone. Serum and mucus levels were determined for each patient at first and fifth day of the two drug regimens. The levels of amoxicillin in the lung tissue collected in patients undergoing pulmonary surgery were also determined after a single oral dose of amoxicillin (1 g) or of amoxicillin (1 g) plus carbocysteine (300 mg). In the bronchial secretions, at the same plasma concentrations, amoxicillin levels were statistically higher after administration of combined substances. These findings indicate the presence of a pharmacokinetic synergism between these compounds, which allows amoxicillin to penetrate more easily through the hemato-bronchial barrier. The association of amoxicillin and carbocysteine, determining an increase of the quantitative levels of antibiotic in the bronchial secretion (also if it is purulent), performs a sterilizing action in a short time with significant therapeutic advantages.

Aged↗
PubMed2006

Comparison of amoxicillin-metronidazole plus famotidine or lansoprazole for amoxicillin-clarithromycin-proton pump inhibitor treatment failures for Helicobacter pylori infection.

BACKGROUND: Proton pump inhibitor-amoxicillin-metronidazole is recommended as second-line Helicobacter pylori therapy in Japan. The authors assessed the efficacy and safety of second-line eradication using the H2-receptor antagonist famotidine as a substitute for proton pump inhibitor. MATERIALS AND METHODS: Sixty-one patients who failed in first-line H. pylori eradication using proton pump inhibitor-clarithromycin-amoxicillin were randomly assigned to either second-line therapy including metronidazole: a 7-day course of lansoprazole 30 mg, amoxicillin 750 mg, and metronidazole 250 mg, b.i.d. (lansoprazole group); or a 7-day course of famotidine 40 mg, amoxicillin 750 mg, and metronidazole 250 mg, b.i.d. (famotidine group). Eradication was assessed for each group at least 4 weeks after completing eradication therapy. Drug susceptibility test was performed using 57 strains in pretreatment to clarithromycin, metronidazole, and amoxicillin. RESULTS: Prior to second-line H. pylori eradication, the rate of resistance to clarithromycin was high at 84% (48/57). Similarly, resistance to metronidazole was low at 5.3% (3/57); however, no amoxicillin-resistant strains were found. The eradication rates for both lansoprazole and famotidine treatment groups were high at 97% (29/30) and 94% (29/31), respectively. CONCLUSIONS: Famotidine treatment including metronidazole-amoxicillin as second-line therapy provided a high eradication rate similar to lansoprazole therapy. Famotidine is therefore expected to serve as a useful H. pylori eradication regimen in patients with proton pump inhibitor allergy, an economic benefit in terms of reduced health-care costs is also anticipated.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2005

Pulmonary damage and bacterial load in assessment of the efficacy of simulated human treatment-like amoxicillin (2,000 milligrams) therapy of experimental pneumococcal pneumonia caused by strains for which amoxicillin MICs differ.

An experimental rat pneumonia model using two amoxicillin-susceptible (MICs, < or =0.015 and 2 microg/ml) and two non-amoxicillin-susceptible (MIC, 4 microg/ml) Streptococcus pneumoniae strains was developed for testing the efficacy of amoxicillin administered to simulate human serum kinetics after treatment with amoxicillin-clavulanate (2,000 and 125 mg, respectively, twice a day, for 2.5 days). The end points for efficacy were reductions in bacterial loads in the lungs and reductions in levels of pulmonary damage. For the amoxicillin-susceptible strains (serotypes 23F and 14), a decrease greater than 4.5 log(10) CFU/pair of lungs was obtained, and the time for which the serum antibiotic concentration (SAC) was higher than the MIC (T(S)(A)(C)(>)(MIC)) was greater than 60% of the dosing interval. For non-amoxicillin-susceptible strains, the decrease in bacterial load was 1.34 to 1.75 log(10) CFU/pair of lungs, with a T(S)(A)(C)(>)(MIC) of 46.7% of the dosing interval. An in vitro study showed that serotype 9V non-amoxicillin-susceptible strains behaved as tolerant-like to concentrations similar to those in the in vivo model. The high and maintained SACs (T(S)(A)(C)(>)(MIC), >46% for all strains) significantly diminished lung injury (affected area of the lung and lung weight), compared to that in controls, by all strains, regardless of the MIC, bactericidal behavior in in vitro killing curves, or the serotype of the infecting strain. These results show the importance of host therapeutic end points in the evaluation of antibiotic efficacy. The antibiotic was more efficacious, for one nonsusceptible strain tested, when the treatment was started early (1 h postinoculation [p.i.]) than when treatment was delayed (24 h p.i.).

Amoxicillin↗
PubMed2003

High-dose rabeprazole-amoxicillin versus rabeprazole-amoxicillin-metronidazole as second-line treatment after failure of the Japanese standard regimen for Helicobacter pylori infection.

BACKGROUND: There is currently no optimal second-line treatment after failure of Helicobacter pylori triple therapy. AIM: To determine effective salvage therapy after failure of lansoprazole-amoxicillin-clarithromycin. METHODS: After failure of lansoprazole-amoxicillin-clarithromycin 123 out-patients were randomized to receive either 2-week rabeprazole (20 mg b.d.) + amoxicillin (1000 mg b.d.) (RA group) or 1-week rabeprazole (10 mg b.d.) + amoxicillin (750 mg twice b.d.) + metronidazole (250 mg b.d.) (RAM group). Eradication was assessed by the 13C-urea breath test. We also evaluated cytochrome p450 (CYP) 2C19 genotype status, determined by polymerase chain reaction - restriction fragment length polymorphism, and susceptibility to clarithromycin and metronidazole. RESULTS: On an intention-to-treat basis, H. pylori infection cure was achieved in 37 of 63 (59%) patients in the RA group and in 49 of 60 (82%) patients in the RAM group. Per protocol-based eradication rates in the RA and RAM groups were 66% (37/56) and 88% (49/56), respectively. In both analytic sets there were significant differences between the treatment groups (P < 0.01 in each). Mild adverse events were observed in eight and five patients from the RA and RAM groups, respectively. Genetic predisposition of CYP2C19 and antibiotic resistance did not influence the treatment outcome either regimen. CONCLUSIONS: The rabeprazole + amoxicillin + metronidazole therapy yielded satisfactory results. In contrast, the cure rate in high-dose rabeprazole + amoxicillin was below an acceptable level.

2-Pyridinylmethylsulfinylbenzimidazoles↗