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Fidaxomicin Side Effects

In Summary

More frequently reported side effects include: vomiting. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to fidaxomicin: oral tablet

In addition to its needed effects, some unwanted effects may be caused by fidaxomicin. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when taking fidaxomicin:

Less common:
  • Abdominal or stomach pain
  • bloating
  • bloody or black, tarry stools
  • chills
  • confusion
  • constipation
  • cough
  • drowsiness
  • fever
  • loss of appetite
  • lower back or side pain
  • muscle tremors
  • nausea
  • painful or difficult urination
  • pale skin
  • rapid, deep breathing
  • restlessness
  • severe constipation
  • shortness of breath
  • sore throat
  • stomach cramps
  • troubled breathing with exertion
  • ulcers, sores, or white spots in the mouth
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vomiting
  • vomiting of blood or material that looks like coffee grounds

Minor Side Effects

Some of the side effects that can occur with fidaxomicin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Abdominal or stomach distension or tenderness
  • acid or sour stomach
  • belching
  • blurred vision
  • difficulty with swallowing
  • dry mouth
  • excess air or gas in the stomach or intestines
  • flushed, dry skin
  • fruit-like breath odor
  • full feeling
  • heartburn
  • increased hunger
  • increased thirst
  • increased urination
  • indigestion
  • itching skin
  • passing gas
  • rash
  • stomach discomfort or upset
  • sweating
  • troubled breathing
  • unexplained weight loss

For Healthcare Professionals

Applies to fidaxomicin: oral tablet


Very common (10% or more): Nausea (11%)
Common (1% to 10%): Vomiting (7%), abdominal pain (6%), gastrointestinal hemorrhage (4%), abdominal distension (less than 2%), abdominal tenderness (less than 2%), dyspepsia (less than 2%), dysphagia (less than 2%), flatulence (less than 2%), intestinal obstruction (less than 2%), megacolon (less than 2%)[Ref]


Common (1% to 10%): Anemia (2%), neutropenia (2%), decreased platelet count (less than 2%)[Ref]


Common (1% to 10%): Drug eruption (less than 2%), pruritus (less than 2%), rash (less than 2%)[Ref]


Common (1% to 10%): Increased hepatic enzymes (less than 2%)[Ref]


Common (1% to 10%): Hyperglycemia (less than 2%), metabolic acidosis (less than 2%), increased blood alkaline phosphatase (less than 2%), decreased blood bicarbonate (less than 2%)[Ref]


Postmarketing reports: Hypersensitivity reactions (dyspnea, angioedema, rash, pruritus)


1. "Product Information. Dificid (fidaxomicin)." Optimer Pharmaceuticals, San Diego, CA.

Not all side effects for fidaxomicin may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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