Vancomycin
Glycopeptide antibiotic
Also Vancocin, Vancomycin hydrochloride, Firvanq, Vancomycin HCl, Vanco, Vancomycin oral
- Evidence
- AStrong human evidence
- FDA status
- FDA approvedas of 2026-10-26
- Route
- Several routes
- Studies cited
- 1 human0 animal or cell
An antibiotic used in hospitals for serious infections like MRSA, and as a pill for gut infection with C. diff. It has been used since 1958 and has strong trial support.
Sold for
Vancomycin is the hospital's last-line antibiotic for MRSA and the standard pill for C. difficile gut infection.
Studies say
Randomized trials and more than 65 years of use support both the intravenous and oral indications, with kidney toxicity and rising resistance as the known costs, hence A.
Why grade A. Vancomycin's use is backed by decades of clinical practice and by randomized trials in which it served as the standard-therapy comparator, including a 246-patient trial in Staphylococcus aureus bloodstream infection and endocarditis where daptomycin was tested against vancomycin or an antistaphylococcal penicillin. Grade A for the approved intravenous and oral uses. 12
FDA. Vancomycin has been FDA-approved since 1958. Intravenous vancomycin is approved for serious infections caused by Gram-positive bacteria including MRSA; oral vancomycin (Vancocin capsules, first approved in 1986, and generics) is approved for Clostridioides difficile-associated diarrhea and staphylococcal enterocolitis. 23
Written from 3 cited sources. Fact-checked 2026-10-27: 15 claims checked, 4 corrected. Last refreshed 2026-10-27. Not physician reviewed.
What this means for you
- What people take it for
- Serious bacterial infections
- Can a US doctor prescribe it?
- Yes, FDA approved for serious infections and C. diff gut infection.
- Properly tested in people?
- Yes, in large controlled trials and decades of use.
Evidence checklist
- Randomised controlled trial Comparator in randomized trialsyes
- Human study over 100 people 246 patients in the cited trialyes
- More than one research group Decades of trials by many groupsyes
- Clinical outcomes, not surrogate markers Infection cure and mortalityyes
- Human safety data beyond case reports Decades of use, known kidney riskyes
Drawn from the cited studies below. A dash means the sources give no information.
What it is
Vancomycin is a glycopeptide antibiotic: a seven-amino-acid peptide core cross-linked and decorated with sugars, produced by the soil bacterium Amycolatopsis orientalis. Eli Lilly isolated it from a soil sample from Borneo in the 1950s, and the FDA approved it in 1958. For years it was a reserve drug because early preparations were impure and toxic; the rise of methicillin-resistant Staphylococcus aureus (MRSA) in the 1980s made it a mainstay. 12
The drug is barely absorbed from the gut. That is a limitation for treating infections in the body, which require an intravenous drip, and an advantage for treating C. difficile, where swallowed vancomycin stays in the intestine at high concentration. 23
How it works
Vancomycin binds to the end of the building blocks that bacteria use to assemble their cell wall (the D-alanyl-D-alanine tail of peptidoglycan precursors), physically blocking the enzymes that link them. The wall weakens and the bacterium bursts. It only works on Gram-positive bacteria because Gram-negative bacteria have an outer membrane the large molecule cannot cross. Resistance, as in vancomycin-resistant enterococci, arises when bacteria swap the target to D-alanyl-D-lactate, which the drug cannot bind. 2
What human research shows
The cited trial, published in the New England Journal of Medicine in 2006 by Fowler and colleagues, randomized 246 patients with Staphylococcus aureus bacteremia, with or without endocarditis, to daptomycin or to standard therapy, which meant vancomycin for methicillin-resistant strains and an antistaphylococcal penicillin for susceptible strains, each with initial low-dose gentamicin. Treatment success at 42 days after the end of therapy was 44.2 percent with daptomycin and 41.7 percent with standard therapy, which met the non-inferiority margin. Vancomycin's role in this trial is typical: it is the benchmark against which new anti-MRSA drugs are measured. 1
The oral indication for C. difficile infection rests on the drug's long clinical record and on two trials described in the Vancocin label, in which 266 adults with C. difficile-associated diarrhea were treated with oral vancomycin. The label also covers staphylococcal enterocolitis and states that intravenous vancomycin does not work for either infection. 3
| Study | Model | Finding |
|---|---|---|
| Fowler 2006 (NEJM) | Humans, n=246 with S. aureus bacteremia or endocarditis, randomized open-label, daptomycin versus vancomycin or antistaphylococcal penicillin | Treatment success 44.2 percent with daptomycin versus 41.7 percent with standard therapy, establishing non-inferiority against the vancomycin-based regimen. 1 |
| Vancomycin prescribing information | FDA label | Approved intravenous indications, with nephrotoxicity, ototoxicity and infusion-reaction warnings. 2 |
| Vancocin capsules prescribing information | FDA label, two trials in 266 adults with C. difficile-associated diarrhea | Supports the oral indications for C. difficile diarrhea and staphylococcal enterocolitis; nausea, abdominal pain and low potassium were the commonest adverse reactions. 3 |
Safety
Intravenous vancomycin can injure the kidneys, particularly at high blood levels, with prolonged courses, or alongside other nephrotoxic drugs, so blood levels are monitored. Rapid infusion causes vancomycin flushing syndrome (formerly called red man syndrome), a histamine reaction with flushing and low blood pressure. The label also warns of hearing damage (tinnitus, hearing loss or vertigo), which can be permanent and is more likely in older patients, at higher doses and alongside other drugs that harm hearing. 2
Oral vancomycin is almost entirely unabsorbed, so systemic side effects are uncommon, though absorption can occur in patients with inflamed bowel or kidney failure. Nausea, abdominal pain and low blood potassium were the commonest adverse reactions in the oral trials. Both routes can select for vancomycin-resistant enterococci in the gut. In the Fowler trial, clinically significant kidney dysfunction occurred in 26.3 percent of standard-therapy patients versus 11.0 percent in the daptomycin arm, and only the standard-therapy arm received initial gentamicin, itself toxic to the kidneys. 123
Questions for your clinician
- Is vancomycin the right choice for my infection or are other options available?
- How are my blood levels and kidney function monitored?
- Is oral or intravenous vancomycin used for my condition?
Questions people ask
Is vancomycin a peptide?
Partly. It is a glycopeptide: a short cross-linked peptide core with attached sugars, made by a soil bacterium and not synthesized. It behaves nothing like the signaling peptides sold online. 2
Why is vancomycin given by IV for some infections and by mouth for others?
It is not absorbed from the gut. For infections in the blood, bone or lungs it has to be infused. For C. difficile, which lives in the colon, swallowing it delivers the drug exactly where it is needed and almost none reaches the rest of the body. 3
Is vancomycin still the standard for MRSA bloodstream infection?
Yes. In the 2006 trial that approved daptomycin for S. aureus bacteremia, vancomycin was the comparator for methicillin-resistant strains, and daptomycin was shown to be non-inferior and was not shown to be better. Vancomycin remains the first-line choice in most guidelines, with daptomycin and others as alternatives. 12
Citations
- Fowler 2006, NEJM: Daptomycin versus standard therapy for bacteremia and endocarditis caused by Staphylococcus aureus pubmed.ncbi.nlm.nih.gov
- FDA 2026: Vancomycin Injection prescribing information (NDA 050671), intravenous use accessdata.fda.gov
- FDA 2021: Vancocin (vancomycin hydrochloride) capsules prescribing information, oral use accessdata.fda.gov