Xifaxan (rifaximin)
Rifamycins Oral Tablet
Last reviewed · Source: First Databank (FDB) drug data
Overview
Rifaximin, a structural analog of rifampin, is a rifamycin antibiotic.
Rifaximin is a semisynthetic derivative of rifampin. Like other rifamycins, rifaximin inhibits RNA synthesis in susceptible bacteria by binding to the beta subunit of bacterial DNA-dependent RNA polymerase.
Due to limited and variable systemic absorption, rifaximin is not suitable for the treatment of systemic bacterial infections. Rifaximin systemic exposure is dose-proportional over a dosage range of 200-400 mg, and systemic exposure is less than dose-proportional over a dosage range of 400-600 mg. Following oral administration of rifaximin (single or multiple doses of 550 mg) in healthy individuals, mean peak plasma concentrations are attained about 1 hour after dosing and range from 2.4-4 ng/mL.
In patients treated with oral rifaximin (200 mg three times daily for 3 days), plasma concentrations and systemic exposure (area under the plasma concentration-time curve (AUC)) are low and variable and accumulation of the drug does not occur. In patients with a history of hepatic encephalopathy receiving rifaximin (550 mg twice daily), the mean AUC of rifaximin is approximately 12-fold higher than that reported in healthy individuals. In patients with irritable bowel syndrome (IBS) with diarrhea receiving rifaximin (550 mg three times daily for 14 days), the time to peak plasma concentrations, mean peak plasma concentrations, and AUC of rifaximin are similar to those reported in healthy individuals.
When rifaximin was administered 30 minutes after a high-fat meal in healthy individuals, peak plasma concentrations of the drug were not affected; however, the time to peak plasma concentrations was delayed from 0.75 to 1.5 hours after the dose and AUC was increased twofold. Rifaximin is moderately bound to human plasma proteins (67.5 or 62% in healthy individuals or patients with hepatic impairment, respectively). Systemically absorbed rifaximin undergoes extensive metabolism, principally by cytochrome P-450 (CYP) isoenzyme 3A4.
Following a 400-mg oral dose of rifaximin, 96.6% of the dose is excreted in feces (mostly as unchanged drug) and 0.3% is excreted in urine (mostly as metabolites). The mean half-life of rifaximin at steady-state is 5.6 hours in healthy individuals and 6 hours in patients with IBS with diarrhea.
Rifaximin is active in vitro and in clinical infections (i.e., infectious diarrhea) against most isolates of enterotoxigenic Escherichia coli (ETEC) and enteroaggregative Escherichia coli (EAEC).
Rifaximin should not be used to treat diarrhea accompanied by fever or blood in the stool, or due to pathogens other than E. coli. Do not use rifaximin in patients where Campylobacter jejuni (C. jejuni), Shigella, and Salmonella are suspected as causative organisms. Rifaximin is not effective against C. jejuni, and has not been proven effective against Shigella and Salmonella.
When selecting or modifying anti-infective therapy, results of culture and in vitro susceptibility testing should be used. In the absence of such data, local epidemiology and susceptibility patterns should be considered when selecting anti-infectives for empiric therapy.
Resistance to rifaximin generally is associated with mutations in the rpoB gene that change the binding site on DNA-dependent RNA polymerase and decrease rifaximin binding affinity. Cross-resistance between rifaximin and other classes of anti-infectives has not been observed.
USES: This medication is used to treat diarrhea caused by the common bacteria known as E. coli ("traveler's diarrhea"). Rifaximin should not be used if you have a fever or bloody diarrhea. It works by stopping the growth of bacteria.
This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections.
Rifaximin is also used to treat irritable bowel syndrome with diarrhea. It is also used to prevent a brain problem caused by liver disease (hepatic encephalopathy).
Generic name: rifaximin
Pronunciation: (rif-AX-i-min)
Drug class: Rifamycins
Therapeutic class: Anti-Infective Agents
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Xifaxan
Indications
The following indications are listed for Xifaxan:
- Diarrhea Predominant Irritable Bowel Syndrome
- Hepatic Encephalopathy
- Traveler's Diarrhea Due To Noninvasive Strain Of Escherichia Coli
Also known as: Diarrhea Predominant Ibs, Diarrhea Predominant Spastic Colon, Portal Systemic Encephalopathy, Traveler's Diarrhea Due To Noninvasive E. Coli.
Dosing
No dosing information is available for this tab.
Rifaximin is administered orally without regard to meals.
Store tablets at 20-25oC (excursions permitted between 15-30oC).
| Drug label | Dosing type | Instructions |
|---|---|---|
| Xifaxan 550 Mg Tablet | Maintenance | Take 1 tablet (550 mg) by oral route 2 times per day. |
No dosing information is available for this tab.
Drug interactions
Rifaximin is a substrate of cytochrome P-450 (CYP) isoenzyme 3A4. Based on in vitro studies, rifaximin is not expected to inhibit CYP1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1, or 3A4. In vitro, rifaximin is a substrate of organic anion transporting polypeptides (OATP) 1A2, 1B1, and 1B3; the drug is not a substrate of OATP2B1.
Although in vitro studies indicate that rifaximin inhibits OATP1B1, 1A2, and 1B3, the effect of the drug on these transporters in vivo is unknown.
Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.
Antibiotics/Fecal Microbiota
SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.
MECHANISM OF ACTION: Fecal microbiota is a suspension of live bacteria, which may be compromised by concurrent use of antibiotics.(1)
CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota. Antibacterial treatment should be completed for 24 to 72 hours before initiating treatment with fecal microbiota. Do not use antibiotics for up to 8 weeks after fecal microbiota.(1)
DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota.
Antibiotics/Fecal Microbiota Spores
SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.
MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1)
CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1)
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1)
DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores.
Antimicrobials/Live Typhoid Vaccine
SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient.
MECHANISM OF ACTION: The antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1)
CLINICAL EFFECTS: Vaccination may be ineffective.
PREDISPOSING FACTORS: None determined.
PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3)
DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3)
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*Hypersensitivity to rifaximin, other rifamycin anti-infectives, or any ingredient in the formulation. Hypersensitivity reactions such as exfoliative dermatitis, angioedema, and anaphylaxis have been reported, some occurring within 15 minutes of a dose of rifaximin.
There are no contraindication contraindications for this drug.
- Intestinal obstruction
- Pregnancy
- Child-pugh class C hepatic impairment
- Disease of liver
Adverse reactions
Hepatic encephalopathy: Adverse effects occurring in >=10% of patients receiving rifaximin include peripheral edema, nausea, constipation, dizziness, fatigue, urinary tract infection, insomnia, anemia, pruritus, and ascites.
IBS with diarrhea: Adverse effects occurring in >=2% of patients receiving rifaximin include nausea and increased ALT concentrations.
Travelers' diarrhea: Adverse effects occurring in >=2% of patients receiving rifaximin include headache.
Less Frequent
- Increased alanine transaminase
Rare or Very Rare
- Abnormal hepatic function tests
- Anaphylaxis
- Angioedema
- Clostridioides difficile infection
- Exfoliative dermatitis
- Hypersensitivity drug reaction
- Rhabdomyolysis
- Stevens-johnson syndrome
- Toxic epidermal necrolysis
More Frequent
- Abdominal pain with cramps
- Dizziness
- Fatigue
- Flatulence
- Headache disorder
- Nausea
- Peripheral edema
Less Frequent
- Arthralgia
- Skin rash
Rare or Very Rare
- Anorexia
- Chest pain
- Dyspnea
- Flushing
- Muscle spasm
- Myalgia
- Pharyngitis
- Pruritus of skin
- Urticaria
- Vomiting
- Weight loss
Precautions
No enhanced messaging available.
Hepatic encephalopathy: Safety and efficacy of rifaximin have not been established in children and adolescents younger than 18 years of age.
Irritable bowel syndrome (IBS) with diarrhea: Safety and efficacy of rifaximin have not been established in children and adolescents younger than 18 years of age.
Travelers' diarrhea: Safety and efficacy of rifaximin have not been established in children younger than 12 years of age.
Data are not available regarding the use of rifaximin in pregnant females. In animal reproduction studies, teratogenic effects (e.g., ocular, oral and maxillofacial, cardiac, and lumbar spine malformations) were observed in rats and rabbits at rifaximin dosages approximately 0.9-5 times and 0.7-33 times, the recommended human dosage (600-1650 mg daily), respectively. Advise pregnant females of the potential risk to the fetus.
It is not known whether rifaximin is distributed into human milk, affects human milk production, or affects the breast-fed infant.
Consider the benefits of breast-feeding and the importance of rifaximin to the female along with the potential adverse effects on the breast-fed child from the drug or from the underlying maternal condition.
The pharmacokinetics of rifaximin have not been specifically studied in geriatric patients 65 years of age or older. Other reported clinical experience has not identified differences in responses between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
Hepatic encephalopathy: There were no overall differences in safety or efficacy between patients 65 years of age and older and younger adults in clinical studies (19% of patients were 65 years of age or older); other reported clinical experience has not identified differences in response between geriatric and younger patients, but greater sensitivity in some older individuals cannot be ruled out.
IBS with diarrhea: There were no overall differences in safety or efficacy between patients 65 years of age and older and younger adults in clinical studies (11% of patients were 65 years of age or older) or other reported clinical experience, but greater sensitivity in some older individuals cannot be ruled out.
Travelers' diarrhea: Experience in patients 65 years of age or older is insufficient to determine whether they respond differently than younger patients.
ICD codes
| Code | Type | Description |
|---|---|---|
| Diarrhea predominant irritable bowel syndrome | ||
| K58.0 | ICD10CM | Irritable bowel syndrome with diarrhea |
| Hepatic encephalopathy | ||
| B15.0 | ICD10CM | Hepatitis A with hepatic coma |
| B16.0 | ICD10CM | Acute hepatitis B with delta-agent with hepatic coma |
| B16.2 | ICD10CM | Acute hepatitis B without delta-agent with hepatic coma |
| B17.11 | ICD10CM | Acute hepatitis C with hepatic coma |
| B19.0 | ICD10CM | Unspecified viral hepatitis with hepatic coma |
| B19.11 | ICD10CM | Unspecified viral hepatitis B with hepatic coma |
| B19.21 | ICD10CM | Unspecified viral hepatitis C with hepatic coma |
| K70.41 | ICD10CM | Alcoholic hepatic failure with coma |
| K71.11 | ICD10CM | Toxic liver disease with hepatic necrosis, with coma |
| K72.01 | ICD10CM | Acute and subacute hepatic failure with coma |
| K72.11 | ICD10CM | Chronic hepatic failure with coma |
| K72.90 | ICD10CM | Hepatic failure, unspecified without coma |
| K72.91 | ICD10CM | Hepatic failure, unspecified with coma |
| K76.82 | ICD10CM | Hepatic encephalopathy |
| Traveler's diarrhea due to noninvasive strain of escherichia coli | ||
| A04.2 | ICD10CM | Enteroinvasive escherichia coli infection |
| A04.4 | ICD10CM | Other intestinal escherichia coli infections |
| A09 | ICD10CM | Infectious gastroenteritis and colitis, unspecified |
ICD code information from First Databank (FDB).
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Last reviewed · Source: First Databank (FDB) drug data
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