Steady-state trough serum and epithelial lining fluid concentrations of teicoplanin 12 mg/kg per day in patients with ventilator-associated pneumonia.

OBJECTIVE: To determine the steady-state trough serum and epithelial lining fluid (ELF) concentrations of teicoplanin 12 mg/kg per day in critically ill patients with ventilator associated pneumonia. DESIGN AND SETTING: Prospective, pharmacokinetic study in the surgical intensive care unit in a university hospital. PATIENTS: Thirteen adult patients with nosocomial bacterial pneumonia on mechanical ventilation were enrolled. INTERVENTIONS: All subjects received a 30-min intravenous infusion of 12 mg/kg teicoplanin every 12 h for 2 consecutive days followed by 12 mg/kg once daily. Teicoplanin concentrations in serum and ELF were determined simultaneously 4-6 days after antibiotic administration started. MEASUREMENTS AND RESULTS: The median total and free concentrations of teicoplanin in serum at trough were 15.9 microg/ml (range 8.8-29.9) and 3.7 (2.0-5.4), respectively. The concentration in ELF was 4.9 (2.0-11.8). CONCLUSIONS: In critically ill patients with ventilator-associated pneumonia the administration of high teicoplanin doses is required to reach sufficient trough antibiotic concentrations in lung tissues at steady state. At that time trough-free concentrations of teicoplanin in serum and ELF are comparable.

Simultaneous determination of metronidazole and spiramycin I in human plasma, saliva and gingival crevicular fluid by LC-MS/MS.

An analytical validation of a new liquid chromatographic-mass spectrometric (LC-MS/MS) method for simultaneous determination of metronidazole and spiramycin I concentrations in human plasma, saliva and gingival crevicular fluid (GCF) is presented. Ornidazole was used as an internal standard, and sample pre-treatment consisted of a liquid-liquid extraction. Chromatographic separation was achieved on a 5 microm Kromasil C18 column (150 mm x 4.6 mm i.d., particle size 5 microm), with a gradient using acetonitrile, water and formic acid at a flow rate of 0.9 ml/min. The methods were validated in terms of intra- and inter-batch precision (<7.1% in plasma, 12% in saliva and 9.2% in GCF, respectively) and accuracy (within +/-8.7% in plasma, within +/-8.7%, except LDQ level within +/-15.4% in saliva and within +/-10.7% in GCF), linearity, specificity, recovery (extraction efficiency), matrix effect, dilution process, stability in human plasma and saliva after three freeze-thaw cycles, stability in human plasma and saliva at ambient temperature and stability of the extracts in the automatic injector of the HPLC system. The methods are applicable for accurate and simultaneous monitoring of the plasma, saliva and gingival crevicular fluid levels of metronidazole and spiramycin I from pharmacokinetic studies.

Concentrations and in vivo antibacterial activity of spiramycin and metronidazole in patients with periodontitis treated with high-dose metronidazole and the spiramycin/metronidazole combination.

OBJECTIVES: Previous studies have shown that metronidazole, alone or in combination with spiramycin (250 mg/1 500 000 units, three times/day), is an effective treatment for active periodontitis, although the dose of metronidazole currently used (750 mg/day) could provide concentrations in gingival crevice fluid that are too low for the MICs of the involved pathogens. This study tested the in vivo antibacterial efficacy of the currently used metronidazole dose (as contained in the fixed spiramycin/metronidazole combination) in patients with an active periodontitis, and of a high dose (1500 mg/day) of metronidazole alone. METHODS: We measured the MICs of spiramycin and metronidazole for the recovered pathogens and the gingival crevice fluid antibiotic concentrations of both antibiotics, and attempted to correlate them with bacterial eradication. RESULTS: The concentrations of metronidazole consistently exceeded the MICs for the pathogens isolated in the corresponding sites, even at the usual metronidazole (250 mg three times/day) dose. All the bacterial species were eradicated during treatment and at follow-up, although Fusobacterium spp. eradicated during treatment reappeared in a majority of the cases at follow-up, 30 days after treatment, in both groups. CONCLUSIONS: The results of antibiotic therapy with metronidazole or the spiramycin/metronidazole combination are consistent with their in vitro antibacterial activity and with the local antibiotic concentrations; they suggest that the currently used metronidazole dose (250 mg, three times/day) alone or as part of the spiramycin/metronidazole combination, could be sufficient for the treatment of active periodontitis.

Randomized comparison of serum teicoplanin concentrations following daily or alternate daily dosing in healthy adults.

Trough serum teicoplanin concentrations were compared in healthy adults following intravenous administration of one of two regimens: (i) 12 mg/kg of body weight every 12 h for 3 doses and then 15 mg/kg every 48 h for 4 doses (n = 16 subjects) or (ii) 6 mg/kg every 12 h for 2 doses and then 6 mg/kg every 24 h for 9 doses (n = 8 subjects). The mean +/- standard deviation trough concentrations in serum on day 11 (24 and 48 h after administration of the last dose for the daily and alternate-day dosing schedules, respectively) were 16.0 +/- 2.1 and 17.9 +/- 3.5 mg/liter for subjects receiving the two regimens, respectively, by a fluorescence polarization immunoassay. The limits of the 95% confidence interval of the difference (-0.2, 3.6 mg/liter) determined by a nonparametric test were situated above the -1.3-mg/liter maximum set difference and indicated a noninferiority of the alternate-day dosing to the daily dosing. Throughout the study the individual trough concentrations in serum in the alternate-day dosing group constantly exceeded 10 mg/liter, the presently recommended target concentration for the treatment of severe infections. The trough concentrations in the sera of all subjects were bactericidal for six Staphylococcus aureus strains for which teicoplanin MICs are between 0.5 and 4 mg/liter. The bactericidal activity of serum was related to total teicoplanin (protein bound and unbound). In conclusion, an alternate-day dosing schedule (15 mg/kg on alternate days following administration of a 12-mg/kg loading dose three times every 12 h) could be considered for further efficacy and safety studies.

Relief of symptoms in patients with group A beta-hemolytic streptococcus tonsillopharyngitis: comparison between telithromycin and penicillin V.

This study compared the resolution of symptoms in patients with group A beta-hemolytic streptococcus tonsillopharyngitis treated with 5 d of telithromycin 800 mg once daily, or 10 d of penicillin V 500 mg 3 times daily. At days 3-5 of treatment, the mean improvement in total symptom score was greater with telithromycin than with penicillin V (p = 0.042). Thus, telithromycin provided faster symptom relief than penicillin V.