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Enhanced effects of amoxycillin/clavulanic acid compared with amoxycillin and clavulanic acid alone on the susceptibility to immunodefenses of a penicillin-resistant strain of Streptococcus pneumoniae.

The recent increase in the incidence of infections due to Streptococcus pneumoniae resistant to penicillin and other antibiotics, often associated with considerable morbidity and mortality, has been recognized as an alarming problem. From the recent medical literature data it emerges that among beta-lactam antibiotics used as an empiric treatment for infections caused by S. pneumoniae, amoxycillin and amoxycillin/clavulanic acid are the most active oral antibiotics and may be considered as a first-line therapeutic agent for the treatment of these infections. Since the therapeutic result of the treatment of an infection is determined by the combined effect of the antimicrobials and host defenses, we investigated the effect of amoxycillin, with and without clavulanic acid, upon the in vitro interaction between human polymorphonuclear leukocytes (PMNs) and a penicillin-resistant strain of S. pneumoniae. Amoxycillin significantly inhibited the streptococcal uptake by PMNs referred to the control system. Clavulanic acid did not have any significant effect upon the interaction PMNs-S. pneumoniae. The addition of amoxycillin/clavulanic acid to phagocytes and streptococci resulted in a synergystic potentiation of the activity of both drugs upon the PMN functions towards S. pneumoniae in such a manner that the bacteria became more susceptible to either the phagocytosis or the microbicidal activities of phagocytes. These effects came in addition to the intrinsic, excellent antimicrobial properties of this drug combination. Although the clinical significance of the observed enhanced effects of amoxycillin/clavulanate are far from elucidated, the possibility exists that they may play a contributory role, especially in patients with impaired host defense.

Amoxicillin↗

Differential effect of impaired renal function on the kinetics of clavulanic acid and amoxicillin.

Amoxicillin and clavulanic acid are prescribed as a fixed drug combination. The purpose of the present study was to assess the influence of various degrees of renal insufficiency (glomerular filtration rate [GFR], less than 5 to greater than 75 ml/min per 1.73 m2) on the pharmacokinetics of amoxicillin and clavulanic acid following oral (500 and 125 mg of amoxicillin and clavulanic acid, respectively) and intravenous (1,000 and 200 mg, respectively) dosing. The volume of distribution and the systemic availability were independent of the renal function, while the total body clearance and the renal and the nonrenal clearance of amoxicillin and clavulanic acid decreased with decreasing renal function. The decrease in the total body clearance was more pronounced for amoxicillin than for clavulanic acid. This explains the increase in the ratio of the area under the plasma concentration versus time curve of amoxicillin to that of clavulanic acid with decreasing glomerular filtration rate after oral dosing; for example for a GFR of 75 ml/min, the ratio of amoxicillin to clavulanic acid was 4.9 +/- 1.2; for a GFR of 35 to 75 ml/min, 5.3 +/- 2.4; for a GFR of 10 to 35 ml/min, 11.9 +/- 5.8; for a GFR of 5 to 10 ml/min, 13.4 +/- 9.1; and for patients on hemodialysis, 14.7 +/- 5.3. Dosage recommendations are suggested which prevent undue accumulations of amoxicillin while maintaining adequate concentrations of clavulanic acid.

Amoxicillin↗

Delayed selective reaction to clavulanic acid: a case report.

Clavulanic acid, an inhibitor of beta-lactamases, is widely used for antimicrobial therapy in association with beta-lactam antibiotics. Despite this, very few adverse reactions to the molecule have been described so far. We report a case of not-immediate reaction to clavulanic acid in a young adult who previously tolerated it. The patient complained of generalized itchy erythema two days after completing a course of amoxicillin-clavulanate therapy, and had no previous clinical history of adverse reactions to drugs. Intradermal and skin prick tests with beta-lactam determinants were negative, as well as the oral tolerance test with amoxicillin. Since no commercial preparation of clavulanic acid alone is available, we performed intradermal and skin prick test with the association amoxicillin-clavulanate, that elicited a delayed (24 and 48 hours) response. IgE-mediated reactions to clavulanic acid are rare, since this molecule is poorly allergenic. Based on the onset time and the specificity of the response we hypothesize that a delayed (possibly T-cell mediated) reaction has occurred.

Adult↗

Pharmacokinetics and urinary excretion of clavulanic acid after oral administration of amoxicillin and potassium clavulanate.

Clavulanic acid is a beta-lactamase inhibitor which prevents microbial lactamase inactivation of beta-lactam antibiotics. The pharmacokinetics and urinary excretion of clavulanic acid were studied in eight healthy adult volunteers after oral administration of 500 mg amoxicillin and 125 mg potassium clavulanate. Serum and urine clavulanic acid concentrations were assayed using high-performance liquid chromatography. Pharmacokinetic parameters were: t 1/2 beta = 1.019 +/- 0.090 hour, t 1/2 alpha = 0.276 +/- 0.031 hour, lag time = 0.321 +/- 0.018 hour, tmax = 1.042 +/- 0.80 hour, Cmax = 2.098 +/- 0.441 micrograms/ml, and AUC = 4.897 +/- 0.979 micrograms X hr/ml. Cumulative urinary excretion of clavulanic acid (as percentage of dose administered) was: 14.05 +/- 2.87 within 2 hours, 25.77 +/- 3.98 within 4 hours, and 27.85 +/- 4.27 within 6 hours after administration.

Administration, Oral↗

Pharmacokinetic study of a paediatric formulation of amoxycillin and clavulanic acid in children.

A combination of amoxycillin and clavulanic acid 4:1 was administered to 35 children (aged 2 to 10 years) with infections. The combination was administered orally as a suspension, every 8 h for 5 to 7 days. Sixteen children (aged 2 to 5 years), received 125 mg amoxycillin and 31.25 mg clavulanic acid, and 19 (6 to 10 years) received 250 mg amoxycillin and 62.5 mg clavulanic acid per dose. Following the first dose serum concentrations of amoxycillin and clavulanic acid were determined by microbiological assay. In the younger group receiving the lower dosage (mean: amoxycillin 9.11 mg/kg and clavulanic acid 2.34 mg/kg), the mean peak concentration of amoxycillin was 3.5 mg/l and of clavulanic acid 1.2 mg/l, occurring 1.32 h and 1.39 h, respectively, after administration. In the older group receiving the higher dosage (mean: amoxycillin 12.35 mg/kg and clavulanic acid 3.14 mg/kg) the mean peak serum level of amoxycillin was 4.0 mg/l and of clavulanic acid 1.3 mg/l, occurring 1.43 h and 1.23 h, respectively, after administration. The higher dose per kilogram body weight resulted in a higher peak serum concentration both of amoxycillin and clavulanic acid. The formulation was well tolerated by all the children and no serious side-effects were recorded. Treatment was considered clinically effective in all cases.

Amoxicillin↗

Pharmacokinetics and serum bactericidal activity of ticarcillin and clavulanic acid.

The pharmacokinetics of ticarcillin 5.0 g and clavulanic acid 0.2 g were examined both alone and combined (3.0 or 5.0 g ticarcillin + 0.2 g clavulanic acid as 3.2 or 5.2 g timentin) after a 15 min infusion in ten healthy volunteers. At the same time, the serum bactericidal activity of 5.0 g ticarcillin alone and 5.2 g Timentin was determined against two ticarcillin resistant strains each of Klebsiella oxytoca and Pseudomonas aeruginosa in the first and sixth hour after administration. The serum kinetics of both ticarcillin and clavulanic acid could best be described by an open 2-compartment model. Both substances showed similar kinetic behaviour in serum with a T 1/2 beta of 74.8 +/- 11.5 min for ticarcillin and 76.6 +/- 4.6 min for clavulanic acid. The total clearance of clavulanic acid was 158 +/- 23 ml/min and thus clearly exceeded that of ticarcillin (112 +/- 9 ml/min). The recovery rate in the 24 h urine was 41.3% for clavulanic acid as compared to 79.4% for ticarcillin. Concomitant administration of both substances led to a limited change in the kinetics of both ticarcillin and clavulanic acid. A significant enhancement of the serum bactericidal action of ticarcillin and clavulanic acid was only detected for both Klebsiella species and not for the Ps. aeruginosa species, and only in the first hour.

Adult↗

Bactericidal effects of ticarcillin-clavulanic acid against Legionella pneumophila pneumonia in immunocompromised weanling rats.

A model of acute Legionella pneumophila pneumonia in neutropenic weanling rats was developed as a means of assessing the efficacies in vivo of the beta-lactams ticarcillin, ticarcillin-clavulanic acid, and clavulanic acid, agents active against the organism in vitro. Weanling rats were dosed with cyclophosphamide 3 days before and immediately prior to infection by intrabronchial intubation with L. pneumophila. The bacteria persisted in the lungs of untreated animals at high counts (5.0 to 7.0 log10 CFU/g of lung tissue) for up to 168 h after infection, and the histological characteristics of the infection were similar to those of the disease in humans. Transmission electron micrography revealed the presence of L. pneumophila multiplying within alveolar macrophages. Therapy with ticarcillin was ineffective in reducing the bacterial numbers in the lung tissue, whereas ticarcillin-clavulanic acid and clavulanic acid were active, producing bactericidal effects similar to those of erythromycin. The ticarcillin-clavulanic acid combination was significantly more efficacious (P less than 0.01) than corresponding doses of clavulanic acid alone. Synergistic activity between ticarcillin and clavulanic acid against L. pneumophila has been demonstrated in vivo, and the combination showed activity similar to that of erythromycin.

Animals↗

The pharmacology of clavulanic acid and ticarcillin combined.

The pharmacokinetics of ticarcillin and clavulanic acid were studied in normal volunteers. Ticarcillin at 50 mg/kg was combined with clavulanic acid at 1.7 and 3.4 mg/kg and infused over 30 minutes. Peak serum levels of ticarcillin were 325 micrograms/ml and its pharmacokinetic parameters were similar when combined with either dose of clavulanic acid. Peak serum levels of clavulanic acid were 8 micrograms/ml for 1.7 mg/kg and 15.8 micrograms/ml for 3.4 mg/kg. Serum concentrations of clavulanic acid were greater than or equal to 1 microgram/ml for 2 h with the 1.7 mg/kg dose and for 3 h with the 3.4 mg/kg dose. Serum half-lives of ticarcillin and clavulanic acid were similar, 1.2 hours. Urinary concentrations of ticarcillin exceeded 100 micrograms/ml and clavulanic acid concentrations exceeded 1 microgram/ml for 6 h. The serum and urine levels were such that many beta-lactamase producing organisms would be inhibited by this combination.

Adult↗

Clinical pharmacology of timentin (ticarcillin and clavulanic acid).

Ticarcillin (4 gm) and clavulanic acid (0.1 gm) were simultaneously administered as timentin to patients with cancer as therapy for infections. The pharmacokinetics of both ticarcillin and clavulanic acid were studied in 15 patients after 30-minute and 2-hour intravenous infusions. The mean (+/- SD) ticarcillin plasma peak concentrations after the two infusions were 341 +/- 76 and 210 +/- 60 micrograms/ml. The plasma terminal t1/2 values of ticarcillin were 80 +/- 32 and 56 +/- 12 minutes. The AUCs were 631 +/- 189 and 601 +/- 230 mg/L X hr. The volumes of distribution of the area were 15 +/- 5 and 21 +/- 7 L and total clearances were 115 +/- 36 and 127 +/- 54 ml/min. The corresponding values for clavulanic acid after the infusions are as follows: mean peak concentrations, 5 +/- 1 and 4 +/- 1 micrograms/ml; plasma terminal t1/2 values, 84 +/- 24 and 74 +/- 36 minutes; AUCs, 11 +/- 3 and 11 +/- 6 mg/L X hr; volumes of distribution of the area, 22 +/- 3 and 32 +/- 6 L; and total clearances, 170 +/- 58 and 175 +/- 68 ml/min.

Adult↗

The pharmacokinetics of ticarcillin, clavulanic acid and their combination.

The pharmacokinetics of ticarcillin and clavulanic acid were examined both alone and combined (3.0 and 5.0 g ticarcillin + 0.2 g clavulanic acid as 3.2 or 5.2 g Timentin) after a 15-min infusion in ten healthy volunteers. The serum kinetics of both ticarcillin and clavulanic acid were described by an open two-compartment model. After the end of the infusion, the serum concentrations of ticarcillin (clavulanic acid) ranged between 576.2 +/- 98.7 mg/l (26.1 +/- 2.6 mg/l) after separate and 621.8 +/- 62.6 mg/l (22.9 +/- 4.6 mg/l) after combined administration. Both substances showed similar kinetic behaviour in serum with a T1/2 beta of 74.8 +/- 11.5 min for ticarcillin and 76.6 +/- 4.6 min for clavulanic acid. The total clearance of clavulanic acid was 158 +/- 23 ml/min and thus clearly exceeded that of ticarcillin (112 +/- 9 ml/min). The recovery rate in the 24 h urine was 41.3% for clavulanic acid as compared to 79.4% for ticarcillin. Concomitant administration of both substances had little effect on the kinetics of either agent alone. With increasing doses of ticarcillin, a decrease of the non-renal clearance of clavulanic acid was observed. The ratio of the two compounds in serum varied from 25:1 (for 5.2 g Timentin, 15:1 for 3.2 g Timentin) at the time of administration to 59:1 (34:1, respectively) 4 h after infusion.

Adult↗

[Microbiological changes in subgingival flora after treatment with amoxicillin-clavulanic acid].

The association amoxicillin-clavulanic acid can be employed as an alternative to the usual antibiotic therapy of periodontitis. The purpose of this study was to determine subgingival microbial changes in 33 patients with periodontitis after using amoxicillin (500 mgrs.-t.i.d.) and clavulanic acid (125 mgrs.-t.i.d.) for 5 days. It resulted clinically in a decrease of both gingival index and plaque index (not significant) and microbiologically in absence of the main bacterial pathogens found pretreatment, such as Bacteroides melaninogenicus, Bacteroides intermedius, Eikenella corrodens and Actinomyces sp., although it was not able to eliminate Actinobacillus asinomycetemcomitans from a juvenile periodontitis and from a prepuberal periodontitis patient. Atibiotic susceptibility testing showed that all bacteria tested were sensitive to this antibiotic. Although this short term study shows good microbial response of main periodontal pathogens, long term studies are necessary to assess the effect of this antibiotic in periodontitis therapy.

Adolescent↗

In vitro activity and in vivo evaluation of ticarcillin plus clavulanic acid against aerobic and anaerobic bacteria.

The efficacy of ticarcillin plus clavulanic acid was compared with that of certain broad-spectrum antibiotics such as ticarcillin, azlocillin, and piperacillin against blood culture isolates of aerobic bacteria obtained from seriously ill patients and anaerobic bacteria obtained from other miscellaneous infections. Ticarcillin plus clavulanic acid was found to be as effective as other broad-spectrum antibiotics against most of the 285 septicemic isolates tested. Ticarcillin plus clavulanic acid was most effective against 351 anaerobic bacteria, including B. fragilis. Further, 32 strains of B. fragilis that were relatively resistant to ticarcillin and azlocillin were tested with a mixture of ticarcillin or azlocillin, each in combination with clavulanic acid. Ticarcillin plus clavulanic acid inhibited all 32 strains of B. fragilis. Addition of clavulanic acid to cephalothin, penicillin, or azlocillin also augmented the antibiotic activity against B. fragilis by 4- to 64-fold. These in vitro data suggest that ticarcillin plus clavulanic acid may be used as a single antibiotic in the cases of bacterial septicemias and that the combination may be used in the treatment of multiple-antibiotic-resistant bacterial strains. In a related study, the augmentation activity of clavulanic acid with penicillin or ticarcillin was evaluated against B. fragilis in a rat intra-abdominal abscess model. Gelatin capsules filled with a mixture of B. fragilis and Escherichia coli were implanted intraperitoneally in male Wistar rats. Four different groups of animals with appropriate controls were treated with penicillin or ticarcillin alone or in combination with clavulanic acid. Treatment was started immediately or delayed for 48 hours after peritoneal soilage. The mortality rate decreased by almost one half when antibiotic therapy was started immediately. Treatment with ticarcillin plus clavulanic acid resulted in a cure in 70 to 89 percent of animals, showing that this combination is the most effective regimen in the treatment of rats with experimental intra-abdominal abscesses caused by B. fragilis and E. coli.

Abscess↗

Inhibition of the beta-lactamases of Branhamella catarrhalis by clavulanic acid and other inhibitors.

The beta-lactamases of Branhamella catarrhalis Ravasio and strain 1908 were readily inhibited by low concentrations of sulbactam, beta-halopenicillanic acids, MM 13902 and clavulanic acid. More detailed studies on the interaction of the Ravasio beta-lactamase with clavulanic acid demonstrated that the enzyme had high affinity for the inhibitor (Ki = 0.07 mumol/L) and was rapidly inhibited (t1/2 = 21 sec, kinhib. = 0.033/sec). Two types of enzyme-inhibitor complex were formed, a transiently stable species (t1/2 = 5.3 minutes at pH 7.3 and 37 degrees C) and a more stable species (t1/2 approximately equal to 2 hours at pH 7.3 and 37 degrees C). Irreversible inactivation of the enzyme was not achieved. Permeability studies on whole cells showed that beta-lactam antibiotics and beta-lactamase inhibitors readily penetrated the outer membrane of B. catarrhalis.

Cell Membrane Permeability↗

Coordinate production of cephamycin c and clavulanic acid by Streptomyces clavuligerus.

Production of cephamycin c and clavulanic acid by Streptomyces clavuligerus was investigated using different media in shake flask condition. Highest cell growth (3.8 g/L) was observed in glycerol, sucrose, proline and glutamic acid (GSPG) medium. Although, GSPG medium supported maximum growth, it was least effective for the synthesis of both cephamycin and clavulanic acid. Yield of cephamycin and clavulanic acid was maximum in dextrin and K medium, respectively. High and low level of constituents of dextrin medium, affected production of both cephamycin and clavulanic acid. Biosynthesis of clavulanic acid was associated with production of cephamycin c.

Anti-Bacterial Agents↗

Pharmacokinetics and distribution of ticarcillin-clavulanic acid (Timentin) in experimental animals.

The pharmacokinetics and distribution of ticarcillin and clavulanic acid were studied in rats and rabbits after intravenous coadministration of the compounds. The elimination half-lives for ticarcillin and clavulanic acid were similar in both rats (ticarcillin, 0.22 h; clavulanic acid, 0.24 h) and rabbits (ticarcillin, 0.38 h; clavulanic acid, 0.31 h). Both compounds distributed widely throughout rat tissues, and the patterns of distribution were similar to those observed for other beta-lactams. Values for penetration into rat pleural, peritoneal, and subcutaneous fluids calculated from the equation (AUCfluid/AUCserum) X 100, where AUC is the area under the concentration-time curve, were between 83 and 93% for ticarcillin and 86 and 103% for clavulanic acid. Values for penetration into tissue cages in rabbits were 139% +/- 45% for ticarcillin and 109% +/- 22% for clavulanic acid. The penetration of clavulanic acid into rabbit cerebrospinal fluid was higher (P less than 0.05) (4.0% +/- 0.61%) than that of ticarcillin (1.3% +/- 0.53%). Overall, the results show that ticarcillin and clavulanic acid distribute readily throughout body tissues and fluids and predict that the penicillin and beta-lactamase inhibitor would be present together at sites of infection.

Animals↗

Comparative activities of clavulanic acid, sulbactam, and tazobactam against clinically important beta-lactamases.

Clavulanic acid, sulbactam, and tazobactam are inhibitors of a variety of plasmid-mediated beta-lactamases. However, inhibition data for these three inhibitors with a wide range of different plasmid-mediated beta-lactamases have not yet been compared under the same experimental conditions. A number of groups have inferred that clavulanic acid inhibits extended-spectrum TEM and SHV beta-lactamases, but inhibition data have rarely been published. In this study, the 50% inhibitory concentrations of these three beta-lactamase inhibitors for 35 plasmid-mediated beta-lactamases have been determined. Of these 35 beta-lactamases, 20 were extended-spectrum TEM- or SHV-derived beta-lactamases. The other 15 enzymes were conventional-spectrum beta-lactamases such as TEM-1 and SHV-1. Clavulanic acid was a more potent inhibitor than sulbactam for 32 of the 35 plasmid-mediated beta-lactamases tested. In particular, clavulanic acid was 60 and 580 times more potent than sulbactam against TEM-1 and SHV-1, respectively, currently the two most clinically prevalent gram-negative plasmid-mediated beta-lactamases. Statistical analysis of the data of the 50% inhibitory concentrations showed that clavulanic acid was 20 times more active overall than sulbactam against the conventional-spectrum enzymes. In addition, clavulanic acid was 14 times more potent than sulbactam at inhibiting the extended-spectrum enzymes. Tazobactam also showed significantly greater activity than sulbactam against the two groups of beta-lactamases. There were no significant differences between the overall activities of tazobactam and clavulanic acid against the extended-spectrum TEM and SHV enzymes and conventional-spectrum enzymes, although differences in their inhibition profiles were observed.

Bacteria↗

The disposition of clavulanic acid in man.

Following oral administration of potassium 14C-clavulanate to four human subjects, at least 73% of the radioactive dose was absorbed. The mean absolute bioavailability was 64%. Absorption was rapid with peak plasma concentrations of radioactivity and clavulanic acid (2-6 micrograms/ml) occurring between 45 min and three hours after dosing. Values for the volume of distribution at steady-state and terminal half-life of clavulanic acid in the plasma were 12.01 and 0.8 h respectively. Following intravenous administration of clavulanic acid to the same subjects, the clearance, and volume of distribution at steady-state were 0.21 l/min, and 12.01, respectively. Clavulanic acid was the major radioactive component present in 0-24 h urine following oral dosing (23% of the dose). The two major metabolites were 2,5-dihydro-4-(2-hydroxyethyl)-5-oxo-1H-pyrrole-3-carboxylic acid (15% of the dose) and 1-amino-4-hydroxybutan-2-one (8.8% of the dose). Clavulanic acid and 1-amino-4-hydroxybutan-2-one were the major components in plasma following oral administration (52 and 21% of plasma radioactivity respectively at two hours after dosing). The major route of excretion of radioactivity following oral administration was via the urine (73% of the dose). Most of this radioactivity was excreted in the first 24 h after dosing (68% of the dose). The renal clearance of clavulanic acid was 0.1 l/min. Elimination of radioactivity also occurred via the expired air (17% of the dose) and the faeces (8% of the dose).

Chromatography, Thin Layer↗

Discrepancies between disk diffusion and broth susceptibility studies of the activity of ticarcillin plus clavulanic acid against ticarcillin-resistant Pseudomonas aeruginosa.

Ticarcillin and clavulanic acid in combination were tested against 40 Pseudomonas aeruginosa isolates resistant to ticarcillin by disk diffusion. A total of 21 isolates (53%) were susceptible to ticarcillin-clavulanate by disk diffusion, under currently recommended criteria for ticarcillin susceptibility. Macro-broth dilution tests (ticarcillin plus clavulanic acid, 2 micrograms/ml) confirmed susceptibility (MIC less than or equal to 64 micrograms/ml) of only 8 (38%) of 21 isolates. Time-kill studies of disk diffusion susceptible isolates indicated 2 log10 or greater killing of most isolates at 6 h in broth containing ticarcillin (64 micrograms/ml) combined with clavulanic acid (1, 2, 5, or 10 micrograms/ml). After 6 h, regrowth was common in all concentrations of clavulanic acid except 10 micrograms/ml. Regrowth populations were resistant to ticarcillin-clavulanate by MIC determination. Poor bactericidal activity of ticarcillin-clavulanate against ticarcillin-resistant P. aeruginosa was confirmed, as most isolates did not undergo 99.9% or greater killing at 24 h in all concentrations of clavulanic acid. Serotype O-11 was our most common serotype and was associated with disk diffusion "pseudosusceptibility." Concomitant disk diffusion testing of ticarcillin-clavulanate and ticarcillin is recommended for testing the susceptibility of P. aeruginosa to ticarcillin-clavulanate by disk diffusion. P. aeruginosa isolates resistant to ticarcillin should as a rule be considered also resistant to ticarcillin-clavulanate, despite apparent susceptibility by disk diffusion.

Clavulanic Acid↗