The use of oral fluoroquinolones in nursing home patients

Retrospective analysis of the safety profile of oral moxifloxacin in elderly patients enrolled in clinical trials

BACKGROUND AND OBJECTIVE

As aging is associated with physiological changes, including renal and hepatic insufficiency, and a higher risk of drug interactions, special attention needs to be directed towards the safety of medications in the elderly. The objective of this analysis was to evaluate the safety of oral moxifloxacin in elderly patients who were enrolled in clinical trials and to compare these results to those of other commonly used antibacterials.

METHODS

Safety data from 27 prospective, randomised, comparative phase II/III trials of oral moxifloxacin included in the Bayer clinical trial database were pooled and analysed by age group (<65 years of age, 65-74 years of age, > or = 75 years of age) and by treatment group (moxifloxacin vs comparator). The primary endpoints included rates of treatment-emergent adverse events (all adverse events regardless of causality), drug-related adverse events, drug-related serious adverse events, deaths and premature discontinuations because of a treatment-emergent adverse event. A treatment by age group interaction test was used to determine if the comparison between moxifloxacin and the comparator group in the incidence rates of any treatment-emergent or drug-related adverse events were affected by increasing age.

RESULTS

Of the 12 231 patients who had valid safety data, 6270 had been treated with oral moxifloxacin and 5961 with a comparator antibacterial. The most frequently used comparators were cefuroxime and clarithromycin. Most patients (n = 9671) were <65 years of age (4939 moxifloxacin, 4732 comparator); 1636 patients were 65-74 years of age (842 moxifloxacin, 794 comparator); and 924 patients were > or = 75 years of age (489 moxifloxacin, 435 comparator). The treatment by age group interaction test revealed that the comparison of drug-related adverse event rates between the moxifloxacin and comparator group were not affected by increasing age (p = 0.43). Rates of premature termination between the moxifloxacin and comparator treatment groups also did not increase with age (p = 0.552). No arrhythmias related to corrected QT (QTc) interval prolongation were reported following oral moxifloxacin or comparator treatment in this large group of young and elderly patients. Overall, the number of deaths was similar between the treatment groups (17 moxifloxacin, 19 comparator).

CONCLUSIONS

Drug-related adverse event rates associated with oral moxifloxacin or the comparator therapy used in these studies did not significantly increase with advancing age. This pooled analysis suggests that oral moxifloxacin can be safely used in elderly patients with characteristics consistent with those enrolled into the clinical trials.

Single-dose pharmacokinetics of oral fleroxacin in bacteremic patients

Fleroxacin is a new broad-spectrum quinolone which can be given by the oral route. The present study was designed to assess the influence of bacteremia on the pharmacokinetics of a single oral dose of fleroxacin. Thirteen patients with proven bacteremia (one or more pairs of positive blood cultures, no hypotension) were given a single 400-mg fleroxacin dose orally on two occasions while also receiving standard antibiotic therapy. The first dose was administered 12 to 36 h after the last positive blood culture was drawn (day 1), and a second dose was administered 7 days later (day 7 +/- 2) to compare the pharmacokinetics between the acute and the convalescent phases of the disease. Following each administration of fleroxacin, serial plasma samples were collected for up to 72 h and were analyzed for unchanged drug by a reversed phase high-pressure liquid chromatography technique. There were no significant changes in the following pharmacokinetic parameters (mean standard deviation) the maximum concentration of drug in serum (6.4 +/- 1.5 versus 6.7 +/- 1.9 mg/liter), the minimum concentration of drug in serum, defined as the concentration of drug in serum at 24 h postdose (3.0 +/- 1.7 versus 2.5 +/- 1.2 mg/liter), the time to the maximum concentration of drug in serum (2.3 +/- 1.4 versus 2.0 +/- 1.2 h), and the elimination half-life (19.7 +/- 8.0 versus 17.9 +/- 6.9 h). Fleroxacin clearances were compared for each individual patient. A positive correlation (R2 = 0.787) was found between the values measured on day 1 and day 7. Oral clearance of fleroxacin (CL = CL/F, where F is bioavailability was slightly, but not significantly, reduced during the bacteremic phase (oral clearance, 43.8+/- 23.5 versus 48.5 +/- 17.5 ml/min.). When compared with previous results obtained in healthy young subjects, longer times to the maximum concentration of drug in serum and elimination half-lives and higher areas under the curve were observed. This could be due to the bacteremic state, the old age of the patients (mean, 66 years), and the low renal clearance (mean calculated creatinine clearance, 71.1 ml/min). A single oral dose of 400 mg of fleroxacin provides sufficient levels in serum to cover susceptible microorganisms for at least 24 h in bacteremic patients. Renal function appeared to be the key element that had to be taken into consideration to adapt fleroxacin dosage profiles in our patient population. Bacteremia itself appeared to amplify that phenomenon, but to a much lesser extent than renal function did.