fidaxomicin
Brand names: Dificid
Fidaxomicin is an antibiotic medicine. It is used to treat diarrhea caused by a bacteria called C. difficile.
Drug Pricing (NADAC)
Brand Price
$238.77/unit
Generic Available
Yes (3 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
Fidaxomicin treats diarrhea caused by Clostridioides difficile (C.
Common side effects
Nausea, Vomiting, Abdominal pain
Key warnings
Do not take fidaxomicin if you are allergic to it or any of its ingredients.
How It Works
Fidaxomicin is a macrolide antibacterial drug. It works by stopping the growth of C. difficile bacteria in your gut. This helps to relieve diarrhea and other symptoms caused by the infection.
How to Take It
Take one 200 mg tablet twice a day. Take it by mouth for 10 days. You can take it with or without food.
Pregnancy & Breastfeeding
It is not known if fidaxomicin will harm an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if fidaxomicin passes into breast milk. Talk to your doctor about the best way to feed your baby if you take this medicine.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is close to your next dose, skip the missed dose and continue with your regular schedule.
Storage
Store fidaxomicin tablets at room temperature, between 68°F to 77°F, in the original bottle.
Side Effects (from patient reports)
Based on 2,065 FDA adverse event reports.
FDA Adverse Event Report Analysis
Detailed analysis of 2,273 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2011–2025.
Total Reports
2,273
Death-Related Reports
248
Hospitalization Reports
699
Top Indication
Clostridium Difficile Infection
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | CLOSTRIDIUM DIFFICILE INFECTION | 461 |
| 2 | DRUG INEFFECTIVE | 398 |
| 3 | DIARRHOEA | 339 |
| 4 | DISEASE RECURRENCE | 178 |
| 5 | CLOSTRIDIUM DIFFICILE COLITIS | 156 |
| 6 | OFF LABEL USE | 128 |
| 7 | NAUSEA | 120 |
| 8 | TREATMENT FAILURE | 119 |
| 9 | ABDOMINAL PAIN | 85 |
| 10 | NO ADVERSE EVENT | 81 |
| 11 | PYREXIA | 74 |
| 12 | DEATH | 69 |
| 13 | VOMITING | 69 |
| 14 | FATIGUE | 55 |
| 15 | ACUTE KIDNEY INJURY | 52 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Do not take fidaxomicin if you are allergic to it or any of its ingredients. Allergic reactions can include trouble breathing, rash, itching, and swelling of the face, mouth, or throat. If you have a severe allergic reaction, stop taking fidaxomicin and get medical help right away.
Known Drug Interactions
7.1 Cyclosporine Cyclosporine is an inhibitor of multiple transporters, including P-gp. When cyclosporine was co-administered with fidaxomicin tablets, plasma concentrations of fidaxomicin and OP-1118 were significantly increased but remained in the ng/mL range [see Clinical Pharmacology ( 12.3 )].
Mechanism: Cyclosporine blocks the proteins that help remove fidaxomicin from your system, which raises the amount of fidaxomicin in your blood.
What to do: Your doctor may monitor you for side effects, but no specific dose changes are usually required.
Common Questions
What is fidaxomicin used for?
How often do I take fidaxomicin?
Can I take fidaxomicin with food?
What should I do if I miss a dose?
What are the common side effects?
Can I take fidaxomicin if I'm allergic to other antibiotics?
Is fidaxomicin safe during pregnancy?
Can I breastfeed while taking fidaxomicin?
How should I store fidaxomicin?
What if I have a severe allergic reaction?
What are the common side effects of fidaxomicin?
Does fidaxomicin interact with other medications?
What drug class is fidaxomicin?
Is fidaxomicin safe during pregnancy?
Related Medications in Macrocyclic Antibiotic
Other drugs grouped near fidaxomicin — same-class peers and common alternatives.
amikacin
Amikin
Amikacin is an antibiotic medicine.
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amoxicillin
Amoxil
Amoxicillin and Clavulanate Potassium is a combination medicine used to fight bacterial infections.
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amoxicillin/clavulanate
Augmentin
Augmentin is a combination of two medicines, amoxicillin and clavulanate.
Compare with fidaxomicin →
ampicillin/sulbactam
Unasyn
Unasyn is a combination of two antibiotics that fights bacteria in your body.
Compare with fidaxomicin →
azithromycin
Zithromax, Z-Pack
Azithromycin is an antibiotic that fights bacteria.
Compare with fidaxomicin →
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What the FDA Data Shows for fidaxomicin
The FDA label for fidaxomicin (sold under brand names such as Dificid) classifies it as a prescription-only medication in the Macrocyclic Antibiotic class. Fidaxomicin treats diarrhea caused by Clostridioides difficile (C. Official labeling lists 6 commonly reported side effects, including Nausea, Vomiting, Abdominal pain.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 2,065 voluntary reports. The database also lists 1 documented drug interaction derived from FDA labeling, with the top-flagged interaction rated minor severity. NADAC pricing from CMS.
Report counts do not establish causation — a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice — always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: January 28, 2026
Read our methodology — how this data is sourced, computed, and verified.
All federal data sources used on this page
- FDA Orange Book — approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed — NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) — post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm — standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files — federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database — current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages