Rifaximin is a synthetic antibiotic, a modification of rifamycin which was originally produced by the microbe Streptomyces mediterranei. Rifaximin should not be confused with rifampicin which is used under brand names and in combined treatments particularly for Tuberculosis infections.
Rifaximin passes through the digestive system virtually unabsorbed and unchanged so retaining its antimicrobial activity and concentration level inside the colon. It is active against a wide range of micro-organisms, including those which grow in low oxygen conditions in the bowel e.g. Clostridia species. These properties do limit its use to the digestive system but, on the other hand there is less chance of side effects in the rest of the body and the risk of bacterial resistance developing is minimised. So far it has proved safe in all test patients (1,2) There has been interest by researchers of many conditions where bowel micro-organisms could play a part ( see table) and so far results have been generally positive
| BOWEL CONDITIONS WHICH MIGHT BENEFIT FROM A REDUCTION IN NUMBER OF MICRO-ORGANISMS |
| Irritable bowel syndromeTravellers diarrhoea
Small intestine bacterial overgrowth C. difficile infections H. pylori and peptic ulcer Excess flatus Food poisoning Gastroenteritis Cryptosporidium infection Hepatic encephalopathy Ulcerative colitis Crohn’s disease Pouchitis Diverticular disease |
Antibiotics are used for DD infections, complications and in surgery, in two ways. In hospitals they can be given intravenously or added to intravenous drips. Capsules and tablets taken by mouth are more likely to be used at primary care level. Readers may have encountered Ciprofloxacin, Metronidazole, or Co-amoxiclav, used alone or in combinations. These antibiotics reach both the colon and surrounding tissues and organs in their blood supply. Rifaximin works only inside the bowel which suggests a different type of use. Reducing or controlling the level of resident gut bacteria may have a preventative role. In the case of diverticular disease it could reduce symptoms and/or reduce the incidence of diverticulosis turning into diverticulitis with its possible serious consequences. Research in this area has been done mainly in Italy. Rifaximin has been tried alone and in combination with existing treatments for uncomplicated DD. Treatment was not continuous but for a few days only each month. Some examples of trial results are:-
- The poor quality of life with symptomatic DD was improved by the cyclic treatment with rifaximin and also with the anti-inflammatory mesalazine. (3)
- In a trial of the effect of bran with and without treatment with rifaximin, the antibiotic significantly reduced symptoms. Rifaximin reduced gas production and shortened transit time probably because it prevented degradation of fibre. (4)
- In patients treated with dietary fibre supplements, those with added rifaximin 7 days per month showed a greater reduction in symptoms and a lower probability of complications. Administration of rifaximin over 2 years was safe and well tolerated. (5)
- The results of a trial treating patients with rifaximin for 10 years suggested its use in preventing the main complications of DD (6)
- Rifaximin was recommended for symptomatic uncomplicated DD because of its safety and tolerability (7)
- 968 outpatients were treated with a fibre supplement of glucomannan and half of them were also given rifaximin for 7 days each month for 12 months. Rifaximin resulted in fewer symptoms (abdominal pain or discomfort, bloating, tenesmus, diarrhoea, abdominal tenderness) and at 12 months approximately twice as many patients were without symptoms and fewer had complications of diverticulitis (8)
Rifaximin has been marketed in Italy under the brand names ‘Normix’ and ‘Rifacol’ since 1988 by Alfa Wassermann SpA (Italy). Over 500 million tablets have been prescribed in 21 countries. It is licensed to Salix Pharmaceuticals Inc in North America under the name ‘Xifaxan’ and was approved by the FDA in 2004 for the treatment of travellers diarrhoea. For several years in this country, rifaximin has been the only treatment for uncomplicated DD likely to be beneficial, according to clinical evicence reports (9). It is included in the best treatments for DD by the British Medical Journal (10).
The problem is that rifaximin is not available in the UK. The manufacturers are planning to apply for registration of rifaximin in the UK but cannot predict when it would be available. The only way an English patient could use it at the present time would be by importing it for compassionate use on a named patient basis. We have increasing hospital admissions due to DD with the implications for NHS costs and patient suffering in the UK. It would be in everybody’s best interest that DD patients should have access to this potentially beneficial treatment.
REFERENCES
- Scarpignato C & Pelosini I. Rifaximin, a poorly absorbed antibiotic: pharmacology and clinical potential. Chemotherapy, 2005, 51suppl 1, 36.
- Scarpignato C & Pelosini I. Experimental and clinical pharmacology of rifaximin, a gastrointestinal antibiotic. Digestion, 2006, 73suppl 1, 13.
- Comparato G et al. Quality of life in uncomplicated symptomatic diverticular disease: is it another good reason for treatment? Dig Dis, 2007, 25, 252.
- D’Inca R et al. Interaction between rifaximin and dietary fibre in patients with diverticular disease. Aliment Pharmacol Ther. 2007, 25, 771.
- Colecchia A etal. Efficacy of long term cyclic administration of the poorly absorbed antibiotic Rifaximin in symptomatic uncomplicated colonic diverticular disease. World J Gastroenterol. 2007, 13, 264.
- Pistoia M A et al. Does rifaximin prevent complications of diverticular disease? A retrospective study. Eur Rev Med Pharmcol Sci. 2004, 8, 283.
- Papi C et al. Management of diverticular disease: is there room for rifaximin? Chemotherapy, 2005, 51suppl 1, 110.
- Latell G et al. Rifaximin improves symptoms of acquired uncomplicated diverticular disease if the colon. Int J Colorectal Dis. 2003, 18, 55.
- Http://www.clinicalevidence.com Colonic diverticular disease (accessed 13.10.06)
- http://besttreatments.bmj.com Colonic diverticular disease (diverticulitis) (accessed 14.9 07)
© Mary Griffiths 2008
With thanks to Alfa Wassermann SpA (Italy) and Salix Pharmaceuticals Inc for information.
NOTE This article appeared in the Summer 2008 magazine of the charity Incontact. The table of bowel conditions was not included. Since this article was written, Rifaximin has been approved in the USA for hepatic encephalopathy. Research into other conditions continues. In symptomatic uncomplicated diverticular disease, treatment with rifaximin plus fibre supplementation was effective in obtaining symptom relief and preventing complications at 1 year. (Bianchi et al. Aliment Pharmacol Ther. 2011, Mar 2, Epub) In the UK, Humes et al. (Clinical Evidence: Colonic Diverticular Disease, Web publication 14 Mar 2011) consider that a placebo-controlled, double-blind RTC should be performed before making any firm recommendations.
Tags: antibiotics, Drugs