rifAXIMin

General

Pronunciation:
ri-fax-i-min

Trade Name(s)

• Xifaxan
• Zaxine 

Ther. Class.

anti-infectives

Pharm. Class.

rifamycins

Indications

• Travelers' diarrhea due to noninvasive strains of Escherichia coli.
• Reduction in risk of overt hepatic encephalopathy recurrence.
• Irritable bowel syndrome with diarrhea.

Action

Inhibits bacterial RNA synthesis by binding to bacterial DNA-dependent RNA polymerase.

Therapeutic Effect(s):

• Decreased severity of travelers' diarrhea.
• Decreased episodes of overt hepatic encephalopathy.
• Decreased signs/symptoms of irritable bowel syndrome with diarrhea.

Spectrum:

Escherichia coli (enterotoxigenic and enteroaggregative strains).

Pharmacokinetics

Absorption: Poorly absorbed (<0.4%); action is primarily in GI tract.

Distribution: 80–90% concentrated in gut.

Metabolism and Excretion: Almost exclusively excreted unchanged in feces.

Half-life: 6 hr.

TIME/ACTION PROFILE

Contraindication/Precautions

Contraindicated in:

• Hypersensitivity to rifaximin or other rifamycins;
• Diarrhea with fever or bloody stools;
• Diarrhea caused by other infectious agents;
• Lactation:  Lactation.

Use Cautiously in:

• OB:  Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
• Pedi:  Safety not established in children <18 yr (hepatic encephalopathy or irritable bowel syndrome with diarrhea) or <12 yr (travelers' diarrhea).

Adverse Reactions/Side Effects

CV: peripheral edema

GI: CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD)

Neuro: dizziness

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

•  P-glycoprotein inhibitors, including  cyclosporine, may ↑ levels and risk of toxicity.
• May cause fluctuations in INR when used with  warfarin ; closely monitor INR.

Route/Dosage

Travelers' Diarrhea

PO (Adults and Children  ≥12 yr): 200 mg 3 times daily for 3 days.

Hepatic Encephalopathy

PO (Adults): 550 mg twice daily.

Irritable Bowel Syndrome With Diarrhea

PO (Adults): 550 mg 3 times daily for 14 days; if recurrence of symptoms, may treat up to an additional two times.

Availability

Tablets: 200 mg, 550 mg

Assessment

• Traveler's Diarrhea: Assess frequency and consistency of stools and bowel sounds before and during therapy.
• Assess fluid and electrolyte balance and skin turgor for dehydration.
• Hepatic Encephalopathy: Assess mental status periodically during therapy.
• Irritable Bowel Syndrome With Diarrhea: Assess frequency and consistency of stools and other irritable bowel syndrome symptoms (bloating, cramping) daily.
• Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care provider promptly as a sign of CDAD. May begin up to several weeks following cessation of therapy.

Lab Test Considerations:

May cause lymphocytosis, monocytosis, and neutropenia.

Implementation

• Do not confuse rifaximin with rifampin.
• PO Administer with or without food.

Patient/Family Teaching

• Explain purpose and side effects of medication to patient. Advise patient to read  Patient Information  before starting therapy. Instruct patient to take as directed and to complete therapy, even if feeling better.
• Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications.
• Advise patient to stop taking rifaximin if diarrhea symptoms get worse, persist >24–48 hr, or are accompanied by fever or blood in the stool. Consult health care provider if these occur. Advise patient not to treat diarrhea without consulting health care provider. May occur up to several weeks after discontinuation of medication.
• May cause dizziness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
• Rep:  Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

• Decreased severity of travelers' diarrhea.
• Decreased episodes of overt hepatic encephalopathy.
• Decreased signs/symptoms of irritable bowel syndrome with diarrhea.