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rifaximin (Rx)Brand and Other Names:Xifaxan

 
 
 

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 200mg
  • 550mg
more...

Traveler's Diarrhea

200 mg PO q8hr for 3 days

Hepatic Encephalopathy

Maintenance of remission

550 mg PO q12hr

Irritable Bowel Syndrome

Indicated for irritable bowel syndrome with diarrhea (IBS-D) in adult men and women

550 mg PO q8hr for 14 days; recurrence of symptoms can be retreated with a 14 day treatment course, up to 2 times

Available in unit-dose package containing 42 tablets (ie, 2 week supply) for this indication

Dosage Forms & Strengths

tablet

  • 200mg
  • 550mg
more...

Traveler's Diarrhea

<12 years: Safety and efficacy not established

≥12 years: 200 mg PO q8hr for 3 days, with or without food

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Interactions

Interaction Checker

rifaximin and

No Results

     
     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Adverse Effects

            >10%

            Flatulence (11%)

            1-10%

            Headache (10%)

            Rectal tenesmus (7%)

            Abdominal pain (7%)

            Defecation urgency (6%)

            Nausea (5%)

            Constipation (4%)

            Pyrexia (3%)

            Vomiting (2%)

            Frequency Not Defined

            Hypersensitivity reactions (including allergic dermatitis)

            Pruritus

            Rash

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            Warnings

            Contraindications

            Hypersensitivity to rifamycin antibiotics

            Cautions

            Not effective in diarrhea complicated by fever, hematochezia, or diarrhea due to pathogens other than Escherichia coli

            Not effective against traveler's diarrhea due to Campylobacter jejuni

            Clostridium difficile-associated diarrhea has been reported

            Efficacy against traveler's diarrhea due to Shigella spp and Salmonella spp not proven

            Discontinue if symptoms worsen or persist >24-48 hr

            Possibility of pseudomembranous colitis

            Monitor patients with severe hepatic impairment for increased systemic exposure

            Coadministration with P-gp inhibitors substantially increases systemic exposure to rifaximin; coadministration of cyclosporine with rifaximin resulted in 83-fold and 124-fold increases in rifaximin mean Cmax and AUC in healthy subjects

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            Pregnancy & Lactation

            Pregnancy category: C

            Lactation: Do not use if nursing or do not nurse

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

            more...
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            Pharmacology

            Mechanism of Action

            Antimicrobial action is a result of binding to the beta-subunit of bacterial DNA-dependent RNA polymerase, resulting in inhibition of transcription

            Hepatic encephalopathy: Inhibits growth of enteric ammonia-producing bacteria to indirectly reduce serum ammonia level

            Irritable bowel syndrome with diarrhea: The exact mechanism of action for IBS-D is not known, but is thought to be related to changes in the bacterial content in the gastrointestinal tract and reduction of gas

            Absorption

            Bioavailability: <0.4%

            Peak plasma time: 1 hr

            Distribution

            Gut: 80-90%

            Metabolism

            Induces CYP3A4 in hepatocytes in vitro

            Elimination

            Half-life: 2-5 hr

            Excretion: Feces (>90%)

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            Administration

            Instructions

            May take with or without food

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            Images

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            Formulary

            FormularyPatient Discounts

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            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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