Ciprofloxacin decreases the rate of ethanol elimination in humans

Abstract

Background-Extrahepatic ethanol metabolism is postulated to take place via microbial oxidation in the colon, mediated by aerobic and facultative anaerobic bacteria. Aims-To evaluate the role of microbial ethanol oxidation in the total elimination rate of ethanol in humans by reducing gut flora with ciprofloxacin. Methods-Ethanol was administered intravenously at the beginning and end of a one week period to eight male volunteers. Between ethanol doses volunteers received 750 mg ciprofloxacin twice daily. Results-A highly significant (p=0.001) reduction in the ethanol elimination rate (EER) was detected after ciprofloxacin medication. Mean (SEM) EER was 107.0 (5.3) and 96.9 (4.8) mg/kg/h before and after ciprofloxacin, respectively. Faecal Enterobacteriaceae and Enterococcus sp. were totally absent after medication, and faecal acetaldehyde production capacity was significantly (p<0.05) decreased from 0.91 (0.15) to 0.39 (0.08) nmol/min/mg protein. Mean faecal alcohol dehydrogenase (ADH) activity was significantly (p<0.05) decreased after medication, but ciprofloxacin did not inhibit human hepatic ADH activity in vitro. Conclusions-Ciprofloxacin treatment decreased the ethanol elimination rate by 9.4%, with a concomitant decrease in intestinal aerobic and facultative anaerobic bacteria, faecal ADH activity, and acetaldehyde production. As ciprofloxacin has no eVect on liver blood flow, hepatic ADH activity, or cytochrome CYP2E1 activity, these eVects are probably caused by the reduction in intestinal flora. (Gut 1999;44:347-352)

Impairment of the Intestinal Barrier by Ethanol Involves Enteric Microflora and Mast Cell Activation in Rodents

“…19 Moreover, some antibiotics have been found to decrease significantly the whole body ethanol metabolism. 20 Our present data support these observations because a twofold increase of ethanol blood concentration was observed after antibiotic treatment in rats or in germ-free mice, in comparison with conventional animals. These results highlight a significant role for the gut microflora in ethanol metabolism, which may be responsible for half of the whole ethanol metabolic activity.…”

Antibiotic treatment of small bowel bacterial overgrowth in patients with Crohn's disease

“…On the contrary, ciprofloxacin is not effective against anaerobic bacteria; 20 however, it has been successfully prescribed for intestinal decontamination in several conditions where the Gram-negative microflora play a key role. 21,22 Our study is the first demonstration of the efficacy of metronidazole and ciprofloxacin in the treatment of small bowel bacterial overgrowth in patients affected by Crohn's disease, even if these drugs have been widely used in the active disease for many years. [11][12][13] In our experience both antibiotics were effective and well tolerated in the treatment of this condition, although ciprofloxacin showed a small, but not statistically significant, gain in terms of efficacy and tolerability compared to metronidazole.…”

Quinolones

“…However, another study, again using healthy volunteers, found that ciprofloxacin 750 mg twice daily significantly reduced the ethanol elimination rate (by mean 9%, range 5-18%) and increased the AUC (mean 12%) and time to zero blood ethanol concentration (mean 10%). This pharmacokinetic interaction was felt to be caused by the effect of ciprofloxacin on the ethanol-metabolizing intestinal flora and not its hepatic effects (on enzymes and blood flow) [295]. Perhaps the discrepancies between results of these two studies are caused by differences in subject numbers (statistical power), drug doses, or study design (randomized, parallel group vs. crossover).…”