Concentrations of trovafloxacin in colonic tissue and peritoneal fluid after intravenous infusion of the prodrug alatrofloxacin in patients undergoing colorectal surgery

New Fluoroquinolones: Real and Potential Roles

The second-generation fluoroquinolones have enjoyed successful clinical use for more than 10 years in many countries, and they have a valued and proven record of safety and efficacy. However, deficiencies with respect to gram-positive and anaerobic organisms limit the use of these agents in respiratory, intra-abdominal, and pelvic infections. New, third-generation agents with dramatically increased activity against gram-positive and anaerobic bacteria--notably, Streptococcus pneumoniae and Bacteroides fragilis--have shown high rates of efficacy in pneumonia, bronchitis, and surgical and gynecologic infections. Although most of these new drugs produce similar clinical results, adverse reaction profiles differ and may influence therapeutic choices.

Overview of quinolones in the treatment and prevention of surgical infection

Postoperative infection remains a complication of surgical procedures, resulting in increased morbidity, mortality, and cost. The frequent polymicrobial etiology and emerging patterns of resistance continue to compromise cure rates. Although quinolones have many attractive properties for the surgical setting, combination therapy is routinely indicated for appropriate coverage. Advanced-generation quinolones, such as trovafloxacin, offer an increased antimicrobial spectrum, including activity against important surgical pathogens, and longer elimination half-lives. These newer agents may be used intravenously or orally as once-daily single-agent therapy for surgical prophylaxis, and in place of combination therapy for complex intra-abdominal and pelvic infections.

A double-blind, placebo-controlled, parallel group study of oral trovafloxacin on bowel microflora in healthy male volunteers

BACKGROUND

Treatment with oral antibiotic drugs generally influences normal fecal flora. These changes can be both beneficial (eg, elimination of aerobic, gram-negative bacilli) and detrimental (eg, the appearance of resistant pathogenic micro-organisms). Trovafloxacin, a new fluoroquinolone with in vitro activity against anaerobes, and gram-negative, gram-positive, and atypical pathogens, is a potentially beneficial antimicrobial for bowel sterilization. This double-blind trial investigated the effect of trovafloxacin on the normal microbial bowel flora of healthy male subjects.

METHODS

Subjects were randomized (in a 2:1 ratio) to receive either 200 mg trovafloxacin once daily for 10 days or a matching placebo. Fecal samples were collected at two baseline occasions, on visit days 4, 7, 10, and 17, and at follow-up. Bacterial species were identified and quantified in the fecal samples.

RESULTS

Twelve subjects received the active drug and seven received placebo. No Enterobacteriaceae were found in samples from days 4 to 10 in subjects receiving trovafloxacin. No changes in Enterobacteriaceae were found throughout the study in subjects receiving placebo. Incidental Enterobacteriaceae were isolated from subjects in the trovafloxacin group at the end of the study. No clinically significant differences were found in either group with respect to prevalence, appearance, or disappearance of aerobic gram-positive cocci, anaerobic bacteria, or yeasts. All tested Enterobacteriaceae were highly susceptible to trovafloxacin. No increase in minimum inhibitory concentration values was seen in day 17 and follow-up samples for isolated Escherichia coli strains. No Clostridium difficile was found in day 17 or follow-up samples from subjects in the trovafloxacin group. All tests for clostridium toxin were negative.

CONCLUSIONS

During the treatment period, E. coli could not be cultured from the feces of the 12 healthy subjects receiving 200 mg trovafloxacin daily during days 4 to 10. All isolated Enterobacteriaceae were susceptible to trovafloxacin and no changes in susceptibility were found after the treatment period. In subjects treated with trovafloxacin, the prevalence and number of gram-positive bacteria were rapidly reduced. Trovafloxacin is able to selectively and reversibly suppress bowel flora.

The pharmacokinetic effects of coadministration of morphine and trovafloxacin in healthy subjects

BACKGROUND

Morphine and antibiotics are frequently coadministered in the surgical setting. These agents may interact, reducing the efficacy of the antibiotic or increasing the toxicity of morphine. It is therefore important to determine whether antibiotics that might be used for surgical prophylaxis have the potential to change the pharmacokinetics of morphine. It is equally important to learn whether morphine affects the plasma levels of antibiotics and thus may potentially influence their efficacy or tolerability.

METHODS

This open, randomized, placebo-controlled, three-treatment, three-period cross-over study enrolled 19 healthy volunteers. Oral trovafloxacin (200 mg), a novel fluoroquinolone antibiotic, and intravenous morphine (0.15 mg/kg) were coadministered, and the effects on the pharmacokinetics of each drug and on changes in the pharmacologic action of morphine, estimated from its effects on respiratory rate and level of sedation, were examined.

RESULTS

When trovafloxacin was coadministered with morphine, the half-life of trovafloxacin was unchanged; however, the ratio of the area under the serum concentration versus time curve (AUC(0-infinity)) estimates for trovafloxacin/morphine versus trovafloxacin/placebo was 63.8% (95% confidence interval [CI], 40.7% to 100.3%), indicating a 36% reduction in the bioavailability of trovafloxacin. The ratio of the mean maximum serum concentration (Cmax) estimates of trovafloxacin for the two treatments was 53.8% (95% CI: 36.1% to 80.1%), indicating a 46% reduction in Cmax. The time to Cmax was delayed by 4 hours. With trovafloxacin coadministration, there were no statistically significant changes in either the mean relative bioavailability of morphine or that of its metabolite, 6beta-glucuronide-morphine. Coadministration of trovafloxacin did not exacerbate the reduction in respiratory rate or increase the number of side effects associated with morphine administration.

CONCLUSIONS

Coadministration of trovafloxacin and morphine reduces the bioavailability and maximum serum concentrations of trovafloxacin. However, elimination of oral trovafloxacin is not impaired, suggesting that the efficacy of trovafloxacin could be maintained in many patients who receive concomitant morphine. Morphine plasma levels and pharmacologic effects are not significantly altered by coadministration of trovafloxacin. Despite their similar metabolic pathways, the trovafloxacin/morphine combination neither exacerbates the respiratory depressant effects of morphine nor increases the frequency of side effects when compared with placebo/morphine treatment. These results suggest that the efficacy of trovafloxacin may be maintained when coadministered with morphine. Concurrent administration of trovafloxacin and morphine is unlikely to alter the pharmacologic effects of morphine.

Double-blind comparison of single-dose alatrofloxacin and cefotetan as prophylaxis of infection following elective colorectal surgery. Trovafloxacin Surgical Group

BACKGROUND

Alatrofloxacin, the prodrug of trovafloxacin, is a novel fluoroquinolone antimicrobial agent with a broad spectrum, including activity against gram-positive and gram-negative aerobes and anaerobes. Its pharmacokinetic properties (long half-life, excellent tissue distribution, and good safety profile) suggest a role in surgical prophylaxis. This prospective, multicenter, double-blind trial compared alatrofloxacin with cefotetan, an approved drug for surgical prophylaxis, in reducing postoperative infections.

METHODS

The efficacy and safety of a single 200-mg intravenous dose of alatrofloxacin were compared to a single 2-g intravenous dose of cefotetan in 492 patients undergoing elective colorectal surgery. The efficacy of alatrofloxacin as a prophylaxis for wound, intra-abdominal, or remote-site postoperative infectious complications was compared with cefotetan in 317 clinically evaluable patients; 161 received alatrofloxacin and 156 received cefotetan. The patients were monitored for infections and safety for 30 days postoperatively.

RESULTS

No statistically significant between-treatment difference was detected in successful clinical response rates at the end of the study (72% for each group). The incidence of primary wound infections at the time of hospital discharge was also similar: 21% in patients treated with alatrofloxacin and 18% in those treated with cefotetan. Safety, established by the incidence of adverse events, did not differ statistically between the groups.

CONCLUSIONS

A single intravenous dose of alatrofloxacin given within 4 hours prior to surgery was as effective as an intravenous dose of cefotetan in the prevention of postoperative infectious complications in patients undergoing elective colorectal surgery. The safety profiles of the two medications were similar.