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What is rifaximin, and how does it work (mechanism of action)?
Rifaximin is a semi-synthetic antibiotic used for treating traveler's diarrhea and hepatic encephalopathy. It is derived from rifamycin, a naturally occurring chemical produced by a bacterium called Streptomyces mediterranei. Rifaximin is active against Escherichia coli bacterial strains that cause traveler's diarrhea, preventing growth of the bacteria by preventing them from manufacturing proteins needed for their replication and survival. By suppressing growth of the bacteria, rifaximin reduces symptoms of traveler's diarrhea. Hepatic encephalopathy is a serious neurologic complication of advanced liver disease that affects the brain. It is believed to be caused by the absorption of ammonia and other chemicals produced by bacteria in the intestine. It is believed that rifaximin prevents and treats hepatic encephalopathy by reducing the intestinal bacteria that produce ammonia. The FDA approved rifaximin in May 2004.
What brand names are available for rifaximin?
Is rifaximin available as a generic drug?
Do I need a prescription for rifaximin?
What are the side effects of rifaximin?
Common side effects associated with rifaximin include:
- urge to defecate,
- abdominal pain,
- flatulence, and
- fluid retention (edema).
Many of these side effects are also symptoms of traveler's diarrhea which rifaximin is used for treating. Rifaximin also causes allergic reactions, rash, and itching. Like other antibiotics rifaximin can alter the normal bacteria in the colon and encourage overgrowth of some bacteria such as Clostridium difficile which causes inflammation of the colon (pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting rifaximin (diarrhea, fever, abdominal pain, and possibly shock,) should contact their physician immediately.
What is the dosage for rifaximin?
The recommended dose for traveler's diarrhea is 200 mg 3 times daily for 3 days and the recommended dose for hepatic encephalopathy is 550 mg twice daily. Rifaximin may be administered with or without meals.
Which drugs or supplements interact with rifaximin?
Rifaximin does not interact with oral contraceptives and does not significantly interact with midazolam. Rifaximin has a low risk of drug interactions because it is poorly absorbed into the blood stream, and it does not significantly affect liver enzymes that break down most drugs.
Is rifaximin safe to take if I'm pregnant or breastfeeding?
The safety of rifaximin in pregnant women has not been adequately evaluated.
It is not known whether rifaximin is excreted in breast milk.
What else should I know about rifaximin?
What preparations of rifaximin are available?
Tablets: 200 and 550 mg
How should I keep rifaximin stored?
Rifaximin should be stored at room temperature at 15 C - 30 C (59 F - 86 F).
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Rifaximin (Xifaxan) is a medication prescribed for the treatment of traveler's diarrhea, non-constipating IBS, and hepatic encephalopathy. Side effects, drug interactions, pregnancy safety, dosing information, and warnings and precautions should be reviewed prior to taking any medication.
Related Disease Conditions
Irritable Bowel Syndrome (IBS)
Irritable bowel syndrome (IBS) is a GI (gastrointestinal) disorder with signs and symptoms that include abdominal pain, bloating, increased gas (flatulence), abdominal cramping, diarrhea, constipation, and food intolerance.Two new tests are now available that may help diagnose irritable bowel syndrome with diarrhea and constipation (IBS-M) irritable bowel syndrome with diarrhea (IBS-D), and irritable bowel syndrome with constipation (IBS-C). Treatment for IBS includes diet changes, medications, and other lifestyle changes to manage symptoms.
Travelers should prepare for their trip by visiting their physician to get the proper vaccinations and obtain the necessary medication if they have a medical condition or chronic disease. Diseases that travelers may pick up from contaminated water or food, insect or animal bites, or from other people include: malaria, meningococcal meningitis, yellow fever, hepatitis A, typhoid fever, polio, and cholera.
Diarrhea is a change is the frequency and looseness of bowel movements. Symptoms associated with diarrhea are cramping, abdominal pain, and the sensation of rectal urgency. Causes of diarrhea include viral, bacterial, or parasite infection, gastroenteritis, food poisoning, and drugs. Absorbents and anti-motility medications are used to treat diarrhea.
Travelers' diarrhea is generally contracted by eating contaminated food or drinking contaminated water. Food is the primary source of travelers' diarrhea. Enterotoxigenic E. coli is the cause of up to 70% of all cases of travelers' diarrhea. There are five unique classes of E. coli that causes gastroenteritis. Other bacteria responsible for travelers' diarrhea include Campylobacter, jejuni, shigella, and salmonella. Viruses such as rotavirus and Norwalk virus (norovirus) and giardia lamblia a parasite may cause travelers' diarrhea. Prevention is careful eating and drinking of water.
SIBO (Small Intestinal Bacterial Overgrowth)
Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least 100,000 bacteria per ml of fluid) are present in the small intestine, but they are more like the bacteria that are found in the colon. There are many conditions associated with SIBO, including: Diabetes Scleroderma Crohn's disease Irritable bowel syndrome (IBS) It has been theorized that SIBO may be responsible for the symptoms of at least some patients with irritable bowel syndrome. Symptoms of SIBO include: Excess gas Abdominal bloating Abdominal pain Treatment for SIBO can include: Antibiotics Probiotics Low FODMAP Diet
Encephalopathy means brain disease, damage, or malfunction. Causes of encephalopathy are varied and numerous. The main symptom of encephalopathy is an altered mental state. Other symptoms include: lethargy, dementia, seizures, tremors, and coma. Treatment of encephalopathy depends on the type of encephalopathy (anoxia, diabetic, Hashimoto's, hepatic, hyper - hypotensive, infectious, metabolic, infections, uremic, or Wernicke's) are examples of types of encephalopathy.
Irritable Bowel Syndrome in Children (IBS)
Irritable bowel syndrome (IBS) in children is a functional gastrointestinal disorder with signs and symptoms of: Abdominal pain Bloating Diarrhea Constipation The cause of IBS is unknown, however, certain foods, stress, anxiety, and depression may contribute to the symptoms of IBS. There is no cure for IBS in children; however, medications, dietary changes, and stress management may relieve symptoms.
Is C. diff (Clostridium difficile) Contagious?
C. diff, or Clostridium difficile, is a bacteria that infects the colon. C. diff bacteria can be found on furniture, bathroom floors, telephones, fingernails, jewelry, toilet seats, and other places. Symptoms of C. diff infection are fever, abdominal pain, and cramps; however, not all people infected with C. diff have symptoms. Treatments for C. diff are antibiotics and surgery in some cases.
IBS-D (Irritable Bowel Syndrome with Diarrhea)
IBS-D or irritable bowel syndrome with diarrhea refers to IBS with diarrhea. Symptoms of IBS-D include intestinal gas (flatulence), loose stools, frequent stools, abdominal pain, diarrhea, and nausea. New non-FDA approved IBS tests may help diagnose IBS and IBS-D. Treatment of IBS-D is geared to toward managing symptoms with diet, medication, and lifestyle changes.
IBS vs. IBD: Differences and Similarities
IBS (irritable bowel syndrome) and IBD (inflammatory bowel disease) are both problems with the digestive tract (gastrointestinal or GI tract), but they are not the same disease. IBS is a functional disorder (a problem with the way the GI tract functions), and IBD is a disease that causes chronic prolonged inflammation of the GI tract, that can lead to ulcers and other problems that may require surgery. The most common forms of IBD are Crohn's disease and ulcerative colitis, or UC. Researchers do not know the exact cause of either disease, but they believe that IBS may be caused and triggered by a variety of factors (foods, stress, and the nervous system of the GI tract), while IBD may be genetic or due a problem with the immune system.Common symptoms of both diseases are an urgent need to have a bowel movement, diarrhea, nausea, vomiting, and abdominal pain and cramping. There are differences between the signs and symptoms of irritable bowel syndrome and inflammatory bowel disease, for example, symptoms unique to IBD are: Fever Joint pain or soreness Skin changes Rectal bleeding Anemia Eye redness or pain Unintentional weight loss Feeling tired Symptoms unique to irritable bowel syndrome include: Sexual problems Fibromyalgia Abdominal bloating Whitish mucous in the stool Changes in bowel movements and in the way stools look An urgent need to urinate Urinating frequently Treatment for IBS is with diet recommendations from a doctor or nutritionist, medication, and lifestyle changes like stress management and avoiding foods that trigger the condition. Treatments for IBD depend upon the type of disease, its symptoms, and health of the patient. Surgery may be necessary for some individuals.REFERENCES: Brown, AC, et al. "Existing Dietary Guidelines for Crohn's Disease and Ulcerative Colitis." Medscape. Lehrer, J. "Irritable Bowel Syndrome." Medscape. Updated: Apr 04, 2017. Rowe, W. "Inflammatory Bowel Disease." Medscape. Updated: Jun 17, 2016. Romanowski, A, MS, RD. "Matching the Right Diet to the Right Patient." Medscape. Jan 27, 2017.
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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
FDA Prescribing information for Xifaxan