rifaximin

(ri-fax-i-min) rifaximin,

Xifaxan

(trade name)

Classification

Therapeutic: anti infectives
Pharmacologic: rifamycins
Pregnancy Category: C

Indications

Travelers' diarrhea due to noninvasive strains of Escherichia coli.Reduction in risk of overt hepatic encephalopathy recurrence.

Action

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

Therapeutic effects

Decreased severity of travelers' diarrhea.Decreased episodes of overt hepatic encephalopathy.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

ROUTE	ONSET	PEAK	DURATION
PO	unknown	unknown	unknown

Contraindications/Precautions

Contraindicated in: Hypersensitivity to rifaximin or other rifamycins;Diarrhea with fever or bloody stools;Diarrhea caused by other infections agents; Lactation: Potential for adverse effects in the infant. Switch to formula for duration of treatment.Use Cautiously in: Obstetric: Use only if benefit to mother outweighs risk to fetus; Pediatric: Safety not established in children <18 yr (hepatic encephalopathy) or <12 yr (travelers' diarrhea).

Adverse Reactions/Side Effects

Central nervous system

dizziness (most frequent)

Cardiovascular

peripheral edema (most frequent)

Gastrointestinal

pseudomembranous colitis (life-threatening)

Interactions

Drug-Drug interaction

Although rifaximin induces the CYP 3A4 enzyme system, since it is not absorbed, drug interactions are unlikely.

Route/Dosage

Travelers' Diarrhea

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

Hepatic Encephalopathy

Oral (Adults) 550 mg twice daily.

Availability

Tablets: 200 mg, 550 mg

Nursing implications

Nursing assessment

Traveler's Diarrhea: Assess frequency and consistency of stools and bowel sounds prior to and during therapy.
Assess fluid and electrolyte balance and skin turgor for dehydration.
Hepatic Encephalopathy: Assess mental status periodically during therapy.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of pseudomembranous colitis. May begin up to several weeks following cessation of therapy.
Lab Test Considerations: May cause lymphocytosis, monocytosis, and neutropenia.

Potential Nursing Diagnoses

Diarrhea (Indications)
Risk for deficient fluid volume (Indications)

Implementation

Do not confuse rifaximin with rifampin.
Oral: Administer with or without food.

Patient/Family Teaching

Instruct patient to take rifaximin as directed and to complete therapy, even if feeling better. Caution patient to stop taking rifaximin if diarrhea symptoms get worse, persist more than 24–48 hr, or are accompanied by fever or blood in the stool. Consult health care professional if these occur. Advise patient not to treat diarrhea without consulting health care professional. 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.
Advise female patients to notify health care professional if pregnant or if pregnancy is suspected, or if breast feeding.

Evaluation/Desired Outcomes

Decreased severity of travelers' diarrhea.
Reduction in risk of overt hepatic encephalopathy recurrence.