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PubMedDate not supplied

A randomized openly comparative study between rifaximin suspension versus rifaximin pills for the eradication of Helicobacter pylori.

BACKGROUND: It has been recently shown that Rifaximin, although given as a suspension, plus omeprazole, may be a promising antibiotic against Helicobacter pylori (H pylori) and worthy of further study. AIM: We have therefore evaluated Rifaximin suspension versus Rifaximin pills, in a randomly openly allocated fashion study, in H pylori positive patients. METHODS: Twenty patients with upper gastrointestinal symptoms (M/F: 13/7, age range 28-68; mean 49.6 yrs) were found to have H. pylori associated gastritis. They were allocated in an open randomized study to two different treatment groups for two weeks: (A) Rifaximin suspension 1800 mg three times a day plus Omeprazole 20 mg twice a day (n = 10), (B): Rifaximin pills 1800 mg three times a day plus Omeprazole twice a day (n = 10). Symptoms such as pirosis, bloating, epigastric pain and nausea were recorded by diary card and were evaluated before and four weeks after stopping treatment. Patients were assessed by endoscopy, histology and urease testing at entry and four weeks after stopping treatments. All the twenty patients were available four weeks after stopping treatment. RESULTS: A statistically significant improvement of the symptoms were found overall after Rifaximin treatments for pirosis, bloating, epigastric pain (p < 0.001 respectively). A significant difference in the symptom's score at the end of the two treatments were recorded between the two groups for bloating alone (p < 0.070). A different and major fall in the neutrophils, between the two treatments was observed with Rifaximin pills compared to Rifaximin suspension. The same observation was obtained according to the intensity of H. pylori reaching an eradication rate of 40% and 60% for Rifaximin suspension versus Rifaximin pills plus omeprazole respectively. In conclusion, these data suggest that Rifaximin pills may be an effective antibiotic against H pylori and worthy of further study.

Adult↗
PubMed2004

Solution structure of rifaximin and its synthetic derivative rifaximin OR determined by experimental NMR and theoretical simulation methods.

The solution structure of rifaximin and its derivative rifaximin OR (open ring) was determined by combining NMR experimental results, theoretical simulation of two-dimensional NMR spectra by complete relaxation matrix analysis (corma), and molecular dynamics calculations. In this study the structural rearrangements due to the opening of the aliphatic chain of rifaximin after the reduction process to form rifaximin OR were investigated. Close spatial proximity of CH(3)(14) and H28b protons detected by 2D-ROESY spectrum of rifaximin OR, which was not present in rifaximin and the down-field shift of CH(3)(34) protons in rifaximin OR (1)H spectrum were crucial to understand the structural modifications, which occurred within the system. The aliphatic chain of rifaximin OR was found to be no longer symmetrical with respect to the aromatic moiety. Although no dramatic structural rearrangements were detected, the aliphatic chain moved toward CH(3)(14), causing a reduction of the aromatic shielding contribution in particular on CH(3)(34).

Anti-Infective Agents↗
PubMed2002

Long-term treatment with mesalazine and rifaximin versus rifaximin alone for patients with recurrent attacks of acute diverticulitis of colon.

BACKGROUND/AIMS: To compare efficacy of combined therapy with rifaximin and mesalazine versus rifaximin alone in treatment of patients with recurrent diverticulitis in order to evaluate: 1) rapidity in improvement of symptoms, 2) regulation of bowel attacks, 3) prevention of recurrence of diverticulitis. METHODS: A total of 218 consecutive eligible patients (131 males, 87 females age 64.3 years, range 51-79), affected by diverticulitis were monitored. Of these, 109 patients were treated with rifaximin 400 mg bid plus mesalazine 800 mg tid for 7 days, followed by rifaximin 400 mg bid plus mesalazine 800 mg bid for 7 days/month (group A); 109 patients were treated with rifaximin 400 mg bid for 7 days, followed by rifaximin 400 mg bid for 7 days/month (group B). Colonoscopy was performed after 3, 6 and 12 months of therapy. RESULTS: At end of follow-up, 193 patients were fully compliant to therapy Two patients died during study (1 in group A, 1 in group B), while four patients were lost to follow-up [1 in group A (0.91%) and 3 in group B (2.75%)]. The only side-effects recorded were transient urticaria (1 in group B, 0.91%) and epigastric pain (9 in group A, 8.25%). Severity of symptoms improved significantly in group A vs group B within 3 months (p < 0.005, p < 0.001 and p < 0.0001 and p < 0.0005 at 3, 6, 9 and 12 months, respectively). Bowel habits inproved significantly in group A vs group B within 3 months (p < 0.005, p < 0.0005, p < 0.001 and p < 0.0001 at 3,6,9 and 12 months respectively). Symptomatic recurrence of diverticulitis occurred in 3 patients in group A, while 13 patients showed recurrence of diverticulitis in group B (p < 0.005) during follow-up. CONCLUSIONS: This study clearly shows that rifaximin plus mesalazine are more effective than rifaximin alone in resolution of symptoms and prevention of recurrence of diverticulitis.

Acute Disease↗
PubMed1987

Sensitivity to rifaximin and rifampicin of Mycobacterium tuberculosis isolated from guinea pigs treated orally with rifaximin.

The in vitro sensitivity of the H 37 RV strain of Mycobacterium tuberculosis to rifaximin and rifampicin was determined by evaluating both the antimycobacterial activity of the two rifamycin derivatives after oral administration to infected guinea pigs and the influence of rifaximin on the susceptibility to rifampicin of the isolated strain from spleen, lungs and liver. The results showed that after oral treatment with rifaximin no changes regarding the sensitivity of the strain to rifaximin and rifampicin were seen.

Animals↗
PubMed1984

Rifaximin (L/105), a new topical intestinal antibiotic: pharmacokinetic study after single oral administration of 3H-rifaximin to rats.

Tritiated rifaximin was administered in a single oral dose of 10 mg/kg (specific activity 8.998 microCi/mg) and 100 mg/kg (specific activity 0.786 microCi/mg) to rats. After treatment, at fixed times, the animals were sacrificed and the radioactivity in plasma, urine, feces, and in the principal organs and tissues was measured. The radioactivity present in the feces of the two groups of rats was more than 95% of the administered dose, while the amounts found in the urine ranged between 1.15% and 1.5% of the dose. In the plasma and tissues the radioactivity levels were very low. This evidence confirmed the scanty gastroenteric absorption of L/105. Furthermore, as the radioactivity levels maintained almost the same value during the trial, there was the possibility that the amounts found were in part due to isotopic exchange between tritium of 3H-L/105 and hydrogen of water.

Administration, Oral↗
PubMed2005

A randomized, double-blind, placebo-controlled trial of rifaximin to prevent travelers' diarrhea.

BACKGROUND: Travelers' diarrhea causes substantial morbidity and postinfectious irritable bowel syndrome. OBJECTIVE: To evaluate nonabsorbable rifaximin for prevention of travelers' diarrhea. DESIGN: Randomized, double-blind, placebo-controlled clinical trial. SETTING: Guadalajara, Mexico. PARTICIPANTS: U.S. students. INTERVENTION: On arrival in Guadalajara, Mexico, 210 U.S. adults received rifaximin (200 mg/d, 200 mg twice daily, or 200 mg 3 times daily) or placebo for 2 weeks. MEASUREMENTS: Participants were followed daily for 3 weeks for enteric disease and symptoms and daily for 5 weeks for drug side effects. Changes in intestinal coliform flora were studied. RESULTS: Travelers' diarrhea developed in 14.74% of participants taking rifaximin and 53.70% of those taking placebo (rate ratio, 0.27 [95% CI, 0.17 to 0.43]). Rifaximin provided 72% and 77% protection against travelers' diarrhea and antibiotic-treated travelers' diarrhea, respectively (P < 0.001 for both), and all rifaximin doses were superior to placebo. In the groups that did not report travelers' diarrhea, rifaximin significantly reduced the occurrence of mild diarrhea (P = 0.02) and moderate and severe intestinal problems (P = 0.009 for pain or cramps; P = 0.02 for excessive gas). Rates of adverse events were comparable in the rifaximin and placebo groups. Minimal changes in coliform flora were found during rifaximin therapy. LIMITATIONS: Rifaximin safely prevented travelers' diarrhea in Mexico, where most cases are caused by diarrhea-producing Escherichia coli. A study is needed in Asia to determine whether rifaximin can prevent diarrhea caused by invasive bacterial pathogens. CONCLUSIONS: Rifaximin prevents travelers' diarrhea with minimal changes in fecal flora, and more liberal chemoprophylaxis against this disease should be considered. Future studies should evaluate whether rifaximin is effective in preventing postinfectious irritable bowel syndrome.

Adult↗
PubMed2005

Comparison of rifaximin and lactulose for the treatment of hepatic encephalopathy: a prospective randomized study.

Rifaximin has been reported to be effective for the treatment of hepatic encephalopathy (HE) in Europe. However, it is unknown whether Rifaximin is effective for the treatment of HE in Koreans, therefore we conducted a open-label prospective randomized study to evaluate the efficacy of rifaximin versus lactulose in Korean patients. Fifty-four patients with liver cirrhosis and hepatic encephalopathy were enrolled. Thirty-two patients were randomized to receive rifaximin and 22 to receive lactulose both over a 7-day periods. Before and at the end of treatment, gradation of blood ammonia, flapping tremor, mental status, number connection test (NCT) were performed and estimation of HE indexes determined. Both rifaximin and lactulose were effective in the majority of patients (84.4% and 95.4%, respectively, p = 0.315). Blood NH3, flapping tremor, mental status, and NCT was significantly improved by rifaximin and lactulose, and the post- treatment levels of these measures were similar for the rifaximin and lactulose-treated groups, as was the HE index (rifaximin group (10.0 --> 4.2, p = 0.000); lactulose group (11.3 --> 5.0, p = 0.000)). One patient treated with rifaximin complained of abdominal pain, which was easily controlled. There was no episode of renal function impairment in either treatment group. Rifaximin proved to be as safe and as effective as lactulose for the treatment of Korean patients with hepatic encephalopathy.

Female↗
PubMed2006

A randomized double-blind placebo-controlled trial of rifaximin in patients with abdominal bloating and flatulence.

AIMS: To study the efficacy of rifaximin, a nonabsorbable antibiotic, in relieving chronic functional symptoms of bloating and flatulence. METHODS: Randomized double-blind placebo-controlled trial consisting of three 10-day phases: baseline (phase 1), treatment with rifaximin 400 mg b.i.d. or placebo (phase 2), and post-treatment period (phase 3). Primary efficacy variable was subjective global symptom relief at the end of each phase. A symptom score was calculated from a symptom diary. Lactulose H2-breath test (LHBT) was performed at baseline and end of study. RESULTS: One hundred and twenty-four patients were enrolled (63 rifaximin and 61 placebo). Baseline characteristics were comparable and none had an abnormal baseline LHBT. Rome II criteria were met in 58.7% and 54.1%, respectively. At the end of phase 2, there was a significant difference in global symptom relief with rifaximin versus placebo (41.3% vs 22.9%, p = 0.03). This improvement was maintained at the end of phase 3 (28.6% vs 11.5%, p = 0.02). Mean cumulative and bloating-specific scores dropped significantly in the rifaximin group (p < 0.05). Among patients with IBS, a favorable response to rifaximin was noted (40.5% vs 18.2%; p = 0.04) persisting by the end of phase 3 (27% vs 9.1%; p = 0.05). H2-breath excretion dropped significantly among rifaximin responders and correlated with improvement in bloating and overall symptom scores (p = 0.01). No adverse events were reported. CONCLUSIONS: Rifaximin is a safe and effective treatment for abdominal bloating and flatulence, including in IBS patients. Symptom improvement correlates with reduction in H2-breath excretion. Future trials are needed to examine the efficacy of long-term or cyclic rifaximin in functional colonic disorders.

Adult↗
PubMed1995

Rifaximin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic potential in conditions mediated by gastrointestinal bacteria.

Rifaximin is a derivative of rifamycin which acts by inhibiting bacterial ribonucleic acid (RNA) synthesis. It is virtually unabsorbed after oral administration; thus it is used primarily to treat local conditions within the gastrointestinal tract. In vitro data indicate rifaximin possesses good activity against species of Staphylococcus, Streptococcus and Enterococcus but lesser activity against species of Enterobacteriaceae. Bacterial resistance during exposure to rifaximin has been reported but its clinical importance remains to be fully defined. Results of comparative trials demonstrate that rifaximin is similar in efficacy to neomycin and lactulose in patients with hepatic encephalopathy and appears to be better tolerated. In 1 study, cyclical administration of rifaximin for 15 days per month was associated with progressive improvement over a 3-month period. In patients with infectious diarrhoea, rifaximin induces more rapid improvement in stool consistency and decreased frequency of faecal evacuations when compared with placebo, and is similar in efficacy to neomycin. Available data suggest rifaximin may be of some use in acute diverticulitis, but its use for the prevention of inflammatory complications or for control of common symptoms of diverticulosis requires further study. Preoperative treatment with rifaximin as antibacterial prophylaxis in colorectal surgery shows some potential but should be further investigated. Overall, rifaximin may be useful as an alternative therapy in hepatic encephalopathy but more data are needed to better define its clinical potential in infectious diarrhoea, diverticular disease and as antibacterial prophylaxis prior to colorectal surgery.

Diarrhea↗
PubMed2002

Rifaximin improves symptoms of acquired uncomplicated diverticular disease of the colon.

BACKGROUND AND AIMS: We examined the efficacy of cyclic long-term administration of rifaximin, a broad spectrum, poorly absorbable antibiotic, in obtaining symptom relief in a large series of patients with uncomplicated diverticular disease, and compared the incidence of episodes of diverticulitis in the group treated with rifaximin to that in a group receiving fiber supplementation only. PATIENTS AND METHODS: In a multicenter, prospective, open trial, 968 outpatients with uncomplicated symptomatic diverticular disease were randomized to either fiber supplementation with 4 g/day glucomannan plus 400 mg rifaximin twice daily for 7 days every month ( n=558) or 4 g/day glucomannan alone ( n=346). Clinical evaluation was performed on admission and at 4-month intervals for 12 months. RESULTS: After 12 months the group treated with glucomannan + rifaximin showed fewer symptoms (abdominal pain/discomfort, bloating, tenesmus, diarrhea, abdominal tenderness) and a lower global symptomatic score. Overall 56.5% of the patients treated with glucomannan + rifaximin and 29.2% of those treated with glucomannan alone were asymptomatic at 12 months ( P<0.001). The rate of complications (diverticulitis and rectal bleeding) was 1.34% in the rifaximin + glucomannan group and 3.22% in the glucomannan alone group ( P<0.05). CONCLUSION: Cyclic administration of rifaximin is effective in obtaining symptom relief in uncomplicated diverticular disease of the colon. The incidence of episodes of diverticulitis in the group treated with rifaximin was lower than that in the group treated with glucomannan alone.

Adult↗
PubMed2006

Antibiotic treatment of Crohn's disease: results of a multicentre, double blind, randomized, placebo-controlled trial with rifaximin.

BACKGROUND: Clinicians often employ antibiotics in Crohn's disease. Rifaximin is active against bacteria frequently found in the intestinal mucosa of Crohn's disease patients. AIM: To evaluate the difference in efficacy between once and twice/daily oral administration of rifaximin and placebo in the treatment of active Crohn's disease. METHODS: We enrolled 83 patients with mild-to-moderate Crohn's disease and randomized to three treatments for 12 weeks: Group A (rifaximin 800 mg o.d. + placebo), Group B (rifaximin 800 mg b.d.) and Group C (placebo b.d.). RESULTS: Clinical remission was achieved by 52% of Group B, 32% (A) and 33% (C). Clinical response was seen in 67% (B), 48% (A) and 41% (C), without reaching a statistically significant difference. Treatment failures were: 4% (B), 12% (A) and 33% (C), (P = 0.010). Remission and response rates of rifaximin 800 mg b.d. were significantly higher than those of placebo and rifaximin 800 mg o.d. in patients with elevated C reactive protein values (P < 0.05). CONCLUSIONS: Rifaximin 800 mg b.d. was superior to placebo in inducing clinical remission of active Crohn's disease. Although this difference was not statistically significant, the number of the failures in the placebo group was significantly higher than those who received rifaximin 800 mg b.d.

Acute Disease↗
PubMedDate not supplied

Rifaximin: a nonabsorbed antimicrobial in the therapy of travelers' diarrhea.

BACKGROUND/AIMS: Bacterial enteropathogens, the major cause of travelers' diarrhea, are customarily treated with antibacterial drugs. Rifaximin, a nonabsorbed antimicrobial was examined as treatment for travelers' diarrhea. METHODS: A randomized, prospective, double-blind clinical trial was carried out in 72 US adults in Mexico. Patients with acute diarrhea received one of three doses of rifaximin (200, 400 and 600 mg t.i.d.) or trimethoprim/sulfamethoxazole (TMP/SMX, 160 mg/800 mg b.i.d.) for 5 days. Results were compared with data from 2 placebo-treated historical control populations. RESULTS: The shortest duration of treated diarrhea was seen in the group receiving 200 mg rifaximin t. i.d (NS). Clinical failure to respond to treatment occurred in 6 of 55 (11%) rifaximin-treated subjects versus 5 of 17 (29%) of TMP/SMX-treated subjects (NS). Sixteen of twenty (80%) of the enteropathogens isolated from the rifaximin-treated subjects and 7 of 7 (100%) from the TMP/SMX group were eradicated by treatment (NS). Sixteen of twenty-four (67%) enteropathogens identified were susceptible to TMP and all 24 were inhibited by</=50 microgram/ml of rifaximin. Rifaximin reduced the number of unformed stools passed during the first 24 h of treatment when compared with 2 control placebo groups (3.3 versus 5.1; p = 0.008 and 0.0001) and led to a reduced duration of post-enrollment diarrhea (mean values of 43.1 versus 68.1 and 81.9 h; p = 0.001). CONCLUSIONS: Rifaximin shortened the duration of travelers' diarrhea compared with TMP/SMX and 2 earlier studied placebo-treated groups. A poorly absorbed drug if effective in treating bacterial diarrhea has pharmacologic and safety advantages over the existing drugs.

Acute Disease↗
PubMed2006

Eradication of Helicobacter pylori: are rifaximin-based regimens effective?

Rifaximin is a non-absorbed semisynthetic rifamycin derivative with a broad spectrum of antibacterial activity including Gram-positive and Gram-negative bacteria, both aerobes and anaerobes. Although originally developed for the treatment of infectious diarrhea, the appreciation of the pathogenic role of gut bacteria in several organic and functional gastrointestinal diseases has increasingly broadened its clinical use. Being the antibiotic active against Helicobacter pylori, even towards clarithromycin-resistant strain, and being the primary resistance very rare, several investigations explored its potential use for eradication of the microorganism. Rifaximin alone proved to be effective, but even the highest dose (1,200 mg daily) gave a cure rate of only 30%. Dual and triple therapies were also studied, with the better results obtained with rifaximin-clarithromycin and rifaximin-clarithromycin-esomeprazole combinations. However, the eradication rates (60-70%) obtained with these regimens were still below the standard set by the Maastricht Consensus guidelines. Although rifaximin-based eradication therapies are promising, new antimicrobial combinations (with and without proton pump inhibitors) need to be explored in well-designed clinical trials including a large cohort of H. pylori-infected patients. The remarkable safety of rifaximin will allow high-dose regimens of longer duration (e.g. 10 or 14 days) to be tested with confidence in the hope of achieving better eradication rates. A drawback of rifaximin could be its inability to reach sufficiently high concentrations in the gastric mucus layer under and within which H. pylori is commonly located and this would likely affect eradication rate. Taking these considerations into account, bioadhesive rifaximin formulations able to better and persistently cover gastric mucosa, or combination with mucolytic agents, such as pronase or acetylcysteine, need to be evaluated in order to better define the place of this antibiotic in our therapeutic armamentarium.

Anti-Infective Agents↗
PubMed2004

Rifaximin: a new treatment for travelers' diarrhea.

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical efficacy, adverse effects, drug interactions and precautions, and dosing recommendations of rifaximin, a new nonabsorbed antimicrobial agent for travelers' diarrhea. DATA SOURCES: A MEDLINE search (1966-July 2004) was conducted to extract human and animal research data in the English language on rifaximin. STUDY SELECTION AND DATA EXTRACTION: Randomized, double-blind, placebo-controlled trials were reviewed and included to evaluate the efficacy of rifaximin in the treatment of travelers' diarrhea. DATA SYNTHESIS: Rifaximin is approved for the treatment of travelers' diarrhea in patients > or =12 years of age with diarrhea caused by noninvasive strains of Escherichia coli. Rifaximin was superior to placebo and trimethoprim/sulfamethoxazole and equivalent to ciprofloxacin in the primary clinical endpoint of the time to the last unformed stool passed. CONCLUSIONS: Rifaximin is a viable alternative to ciprofloxacin for the treatment of travelers' diarrhea. As rifaximin is not systemically absorbed, it offers the advantage of leading to the development of less resistance compared with systemically absorbed antibiotics, in addition to fewer systemic adverse effects and drug interactions. However, the potential for cross-resistance between rifaximin and rifampin, as well as with other classes of antibiotics, is of concern and needs to be elucidated.

Diarrhea↗
PubMed2006

Safety and tolerability of the antibacterial rifaximin in the treatment of travellers' diarrhoea.

Although travellers' diarrhoea can sometimes be associated with postinfectious complications, the condition is typically self-limiting. The infectious-diarrhoea guidelines subcommittees of the Infectious Disease Society of America and the American College of Gastroenterology recommend empirical antibacterial therapy for travellers' diarrhoea. Because therapy is directed largely at relieving symptoms and minimising inconvenience, the chosen antibacterial should ideally be both efficacious and pose a low risk of adverse effects. This review discusses the safety and tolerability of rifaximin in the treatment of travellers' diarrhoea, with a focus on data from controlled clinical trials. Data were obtained from a MEDLINE search using the key word 'rifaximin' with no date limits and from the rifaximin New Drug Application submitted to the US FDA for approval to market rifaximin in the US.Currently, the antibacterials considered as standard treatment for travellers' diarrhoea are systemically absorbed, carry defined risks of adverse effects, and have many uses other than the treatment of enteric disease. The minimally absorbed (<0.4%) oral antibacterial rifaximin constitutes a non-systemic approach to antidiarrhoeal therapy that should overcome some of the limitations of current antibacterials used for travellers' diarrhoea. Rifaximin is differentiated from these, and most other antibacterials, by having a tolerability profile comparable with that of placebo and minimal potential for drug interactions. To date, clinically relevant resistance to rifaximin has not been observed. As the first nonabsorbable antibacterial to be marketed for travellers' diarrhoea, rifaximin should help to change the management paradigm for travellers' diarrhoea and other gastrointestinal illnesses from a systemic approach to a predictably safer, non-systemic approach.

Anti-Infective Agents↗
PubMed2006

Rifaximin, a nonabsorbed oral antibiotic, prevents shigellosis after experimental challenge.

BACKGROUND: This double-blind, placebo-controlled study was conducted to assess the efficacy of the nonabsorbed oral antibiotic rifaximin to prevent shigellosis in volunteers challenged with Shigella flexneri. METHODS: Volunteers were randomized to receive either prophylactic rifaximin (200 mg 3 times daily for 3 days; n = 15) or placebo (n = 10) on days 0, 1, and 2. On day 1, volunteers were challenged with approximately 1500 colony-forming units of S. flexneri 2a strain 2457T given orally in sodium bicarbonate buffer. RESULTS: The incidence of diarrhea was 0 with rifaximin, compared with 60% with placebo (P = .001). The median time to onset of diarrhea was 78.5 h with placebo (P < .001). The incidence of dysentery was 0 for rifaximin and 10% for placebo (P = .4). The incidence of colonization with Shigella was 0 with rifaximin, compared with 50% with placebo (P < .005). A significant serum or mucosal immune response after challenge by at least 1 indicator (immunoglobulin A titer, immunoglobulin G titer, and immunoglobulin A antibody-secreting cell count) was 0 with rifaximin and 80% with placebo (P < .001). CONCLUSIONS: Rifaximin was effective and well tolerated, compared with placebo, in preventing shigellosis in this double-blind study of volunteers challenged with S. flexneri 2a.

Adult↗
PubMed2002

Inhibition of intestinal bacterial translocation with rifaximin modulates lamina propria monocytic cells reactivity and protects against inflammation in a rodent model of colitis.

BACKGROUND: A modification of the intestinal flora and an increased bacterial translocation is a common finding in patients with inflammatory bowel disease as well as in animal model of colitis. Rifaximin, a non-absorbable derivative of rifamycin, is an effective antibiotic that acts by inhibiting bacterial ribonucleic acid synthesis. AIMS: In the present study, we investigated the effect of the administration of rifaximin (10, 30 and 50 mg/kg/day) or prednisolone (10 mg/kg/day) in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. METHODS: Colitis was induced in mice by intrarectal administration of TNBS (1.5 mg/mouse in 50% ethanol) and disease severity assessed clinically and by histologic scoring of colon damage, determination of interleukin (IL)-2, IL-12, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha (protein and mRNA and myeloperoxidase (MPO) activity in the colon. Cytokines production by the lamina propria mononuclear cells (LPMC) and luminal bacteria were also measured. RESULTS: Rifaximin administration (30 or 50 mg/kg/day) increased survival rates of colitic mice and reduced colitis severity as demonstrated by improvement of wasting syndrome, histologic scores, decrease in colon IL-2, IL-12, IFN-gamma and TNF-alpha (protein and mRNA) levels, and diminished colon MPO activity. Rifaximin administration caused a significant reduction of colon bacterial translocation towards mesenteric lymph nodes. LPMC obtained from rifaximin-treated mice released significantly lower amount of IFN-gamma in response to ex vivo stimulation with agonistic anti-CD3 and anti-CD28 antibodies. Rifaximin (50 mg/kg/day) significantly accelerates recovery in mice with established colitis. CONCLUSIONS: Luminal bacterial microflora plays a role in the pathogenesis of TNBS-induced colitis in mice. Rifaximin administration reduces the development of colitis and accelerates healing of established disease by preventing bacterial translocation.

Acute Disease↗
PubMed2005

Rifaximin: a review of its use in the management of traveller's diarrhoea.

Oral rifaximin, a semisynthetic rifamycin derivative, is an effective and well tolerated antibacterial for the management of adults with non-invasive traveller's diarrhoea. Rifaximin was significantly more effective than placebo and no less effective than ciprofloxacin in reducing the duration of diarrhoea after treatment initiation for illness contracted during travel to diverse geographic locations. While rifaximin is effective in patients with Escherichia coli-predominant traveller's diarrhoea, it appears ineffective in patients infected with inflammatory or invasive enteropathogens. Rifaximin has a broad spectrum of antibacterial activity in vitro and undergoes negligible systemic absorption (<0.4%). In contrast to systemically absorbed antibacterials, such as the fluoroquinolones and macrolides, the acquisition of resistance to rifaximin would have limited consequences for global public health, as rifaximin has no role in the management of systemic infections. Rifaximin shows promise as chemoprophylaxis against traveller's diarrhoea and is a valuable new option for the management of traveller's diarrhoea caused by non-invasive bacterial strains.

Anti-Bacterial Agents↗