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Rifaximin Side Effects

For the Consumer

Applies to rifaximin: oral tablet

Along with its needed effects, rifaximin may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking rifaximin:

More common
  • Black, tarry stools
  • dizziness or lightheadedness
  • muscle spasm
  • rapid breathing
  • shortness of breath
  • trouble sleeping
Less common
  • Blood in the urine
  • bloody nose
  • chest pain
  • continuing ringing or buzzing or other unexplained noise in the ears
  • fainting
  • feeling of constant movement of self or surroundings
  • increased heart rate
  • sensation of spinning
  • sunken eyes
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
Incidence not known
  • Cracks in the skin
  • hives or welts, itching skin, or rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • loss of heat from the body
  • red, swollen skin
  • redness of the skin
  • scaly skin

Some side effects of rifaximin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common
  • Bloated
  • difficulty with moving
  • excess air or gas in the stomach or intestines
  • fever
  • frequent urge to defecate
  • full feeling
  • headache
  • lower back or side pain
  • muscle pain or stiffness
  • pain in the joints
  • passing gas
  • stomach pain
  • straining while passing stool
  • swelling of the hands, ankles, feet, or lower legs
Less common
  • Abnormal dreams
  • blurred vision
  • chills
  • confusion
  • cough
  • decreased urination
  • difficulty having a bowel movement (stool)
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • dry lips
  • dry mouth
  • ear pain
  • feeling of warmth
  • hearing loss
  • lightheadedness
  • loss of appetite
  • loss of taste
  • nausea
  • painful or difficult urination
  • pale skin
  • redness of the face, neck, arms, and occasionally, upper chest
  • sore throat
  • sweating
  • swollen glands
  • thirst
  • vomiting
  • wrinkled skin

For Healthcare Professionals

Applies to rifaximin: oral tablet


When used for the treatment of travelers' diarrhea, the most common side effect was headache. This drug was discontinued due to side effects in 0.4% of patients; such side effects were taste loss, dysentery, decreased weight, anorexia, nausea, and nasal passage irritation.

When used for reduction in risk of overt hepatic encephalopathy recurrence, the most common side effects were peripheral edema, nausea, dizziness, fatigue, and ascites.

When used for the treatment of irritable bowel syndrome with diarrhea, the most common side effects were nausea and increased ALT.[Ref]


Very common (10% or more): Nausea (up to 14.3%), ascites (11.4%), flatulence (up to 11%)
Common (1% to 10%): Abdominal pain, abdominal distension, rectal tenesmus, upper abdominal pain, defecation urgency, constipation, stomach discomfort, vomiting, lower abdominal pain, abdominal tenderness, dry mouth, esophageal variceal bleed, diarrhea, bloating and distension, nausea and vomiting symptoms
Uncommon (0.1% to 1%): Dry lips, dyspepsia, gastrointestinal motility disorder, hard feces, hematochezia, mucous stools, taste disorders
Frequency not reported: Blood in stool, dysentery, fecal abnormality, gingival disorder, inguinal hernia, straining, bad taste in mouth, Clostridium colitis
Postmarketing reports: Clostridium difficile-associated colitis[Ref]


Very common (10% or more): Peripheral edema (15%), fatigue (up to 12.1%)
Common (1% to 10%): Pyrexia, chest pain, pain, generalized edema, influenza-like illness, contusion, fall, procedural pain
Uncommon (0.1% to 1%): Ear pain, clostridial infection, candidiasis, hot flush, edema, herpes simplex, asthenic conditions, chills, pain and discomfort
Rare (less than 0.1%): Asthenia
Frequency not reported: Motion sickness, malaise, hot flashes
Postmarketing reports: Clostridial infections (Clostridium difficile)[Ref]

Nervous system

Very common (10% or more): Dizziness (up to 13%), headache (10%)
Common (1% to 10%): Vertigo, amnesia, disturbance in attention, hypoesthesia, memory impairment, tremor
Uncommon (0.1% to 1%): Balance disorders, convulsion, attention disorders, migraine, paresthesia, sinus headache, somnolence
Frequency not reported: Syncope, tinnitus, loss of taste
Postmarketing reports: Presyncope, syncope[Ref]


Hypersensitivity reactions have occurred as early as within 15 minutes of drug administration.[Ref]

Frequency not reported: Anaphylactic reactions
Postmarketing reports: Hypersensitivity reactions (including exfoliative dermatitis, rash, angioneurotic edema [swelling of face and tongue and difficulty swallowing], urticaria, pruritus, flushing, anaphylaxis), anaphylactic responses, angioedemas, hypersensitivity[Ref]


Common (1% to 10%): Pruritus, rash, cellulitis
Uncommon (0.1% to 1%): Eruptions and exanthemas, sunburn, hyperhidrosis/increased sweating, cold sweat
Frequency not reported: Clamminess
Postmarketing reports: Dermatitis, eczema, erythemas, pruritus, purpura, urticarias[Ref]


Common (1% to 10%): Muscle spasms, arthralgia, back pain, myalgia, pain in extremity
Uncommon (0.1% to 1%): Neck pain, muscular weakness
Frequency not reported: Increased blood creatine phosphokinase[Ref]


Common (1% to 10%): Anemia
Uncommon (0.1% to 1%): Lymphocytosis, monocytosis, neutropenia
Postmarketing reports: Thrombocytopenia, INR abnormalities[Ref]


Common (1% to 10%): Cough, nasopharyngitis, dyspnea, upper respiratory tract infection, rhinitis, pneumonia, epistaxis
Uncommon (0.1% to 1%): Pleural effusion, pharyngitis, oropharyngeal pain, rhinorrhea, dry throat, nasal congestion
Rare (less than 0.1%): Chronic obstructive pulmonary disease
Frequency not reported: Respiratory tract infection, nasal passage irritation, pharyngolaryngeal pain[Ref]


Common (1% to 10%): Depression, insomnia, confusional state
Uncommon (0.1% to 1%): Anxiety, hypersomnia, abnormal dreams, depressed mood, nervousness[Ref]


Common (1% to 10%): Increased weight, anorexia, dehydration, hyperglycemia, hyperkalemia, hypoglycemia, hyponatremia
Uncommon (0.1% to 1%): Decreased appetite
Frequency not reported: Decreased weight[Ref]


Common (1% to 10%): Hypotension
Uncommon (0.1% to 1%): Palpitations, increased blood pressure
Rare (less than 0.1%): Hypertension[Ref]


Uncommon (0.1% to 1%): Urinary tract infection, dysuria, polyuria, proteinuria, pollakiuria, blood in urine present, glycosuria, polymenorrhea
Frequency not reported: Choluria, hematuria, urinary frequency[Ref]


Common (1% to 10%): Increased ALT
Uncommon (0.1% to 1%): Increased AST
Postmarketing reports: Liver function test abnormalities[Ref]


Uncommon (0.1% to 1%): Diplopia[Ref]


1. Cerner Multum, Inc. "Australian Product Information." O 0

2. "Product Information. Xifaxan (rifaximin)." Salix Pharmaceuticals, Raleigh, NC.

3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

4. "Rifaximin (Xifaxan 550) for hepatic encephalopathy." Med Lett Drugs Ther 52 (2010): 87

5. Pimentel M, Park S, Mirocha J, Kane SV, Kong Y "The effect of a nonabsorbed oral antibiotic (rifaximin) on the symptoms of the irritable bowel syndrome: a randomized trial." Ann Intern Med 145 (2006): 557-63

6. Juillerat P, Pittet V, Felley C, et al. "Drug safety in Crohn's disease therapy." Digestion 76 (2007): 161-8

7. Garey KW, Salazar M, Shah D, Rodrigue R, Dupont HL "Rifamycin antibiotics for treatment of Clostridium difficile-associated diarrhea." Ann Pharmacother 42 (2008): 827-35

8. Trapnell CB, Connolly M, Pentikis H, Forbes B, Bettenhausen DK "Absence of effect of oral rifaximin on the pharmacokinetics of ethinyl estradiol/norgestimate in healthy females." Ann Pharmacother 41 (2007): 222-8

9. Hynicka LM, Silva KN "Probable rifaximin-induced neutropenia." Am J Health Syst Pharm 69 (2012): 583-6

Some side effects of rifaximin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.