rifaximin, Xifaxan (cont.)

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Medical and Pharmacy Editor:

DOSING: 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.

DRUG INTERACTIONS: 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.

PREGNANCY: The safety of rifaximin in pregnant women has not been adequately evaluated.

NURSING MOTHERS: It is not known whether rifaximin is excreted in breast milk.

SIDE EFFECTS: Common side effects associated with rifaximin include nausea, vomiting, constipation, urge to defecate, dizziness, fatigue, headache, abdominal pain, fever, 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.

REFERENCE: FDA Prescribing information for Xifaxan


Last Editorial Review: 2/11/2011 2:41:00 PM



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