Yes, vancomycin is one of the primary antibiotics used to treat Clostridioides difficile (C. diff) infection. It works by killing the bacteria directly in the gut and has a cure rate between 86% and 93%, depending on the strain involved. For decades it was considered the gold standard, and while newer options now exist, vancomycin remains a widely used and effective treatment.
How Vancomycin Works Against C. Diff
Vancomycin is a type of antibiotic that kills bacteria by blocking them from building their cell walls. Specifically, it attaches to a key building block in the wall’s structure, preventing the bacterium from assembling the protective outer layer it needs to survive. Without an intact cell wall, C. diff bacteria die off.
One important detail: vancomycin for C. diff must be taken by mouth, not through an IV. When given intravenously, the drug travels through the bloodstream but doesn’t reach high enough concentrations inside the colon, which is where C. diff lives and causes damage. Oral vancomycin passes through the digestive tract and delivers the drug directly to the site of infection.
What a Standard Course Looks Like
The standard regimen is 125 mg taken by mouth four times a day for 10 days. This applies to both non-severe and severe initial episodes. Most people start to feel better relatively quickly. Diarrhea and other symptoms typically begin resolving within three to five days of starting treatment, though you should finish the full course even after symptoms improve.
Vancomycin comes in capsule form, but pharmacies also sometimes prepare a liquid solution compounded from the intravenous version of the drug. The liquid is significantly cheaper, though it’s not FDA-approved as an oral formulation and may not be covered by insurance.
Cure Rates and Recurrence Risk
Vancomycin cures the majority of C. diff infections. In clinical trials, the cure rate was about 93% for standard strains and roughly 86% for the more aggressive BI strain, which is associated with outbreaks in healthcare settings.
The bigger challenge with vancomycin is recurrence. About 25% of patients treated with vancomycin experience a return of the infection after their initial course ends. For the aggressive BI strain, recurrence climbed to around 31%. This is the main reason newer alternatives have gained traction: fidaxomicin, for example, cuts recurrence rates roughly in half compared to vancomycin while achieving similar initial cure rates.
How Vancomycin Compares to Fidaxomicin
Current guidelines from the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA) suggest fidaxomicin over vancomycin for an initial C. diff episode, primarily because of its lower recurrence rate. However, the recommendation is conditional, not absolute. Vancomycin is explicitly described as an acceptable alternative, and in many cases it’s the more practical choice.
Cost plays a major role in that decision. Vancomycin capsules in the United States often run several hundred dollars and can exceed $1,000 for a 10-day course, even as a generic. Fidaxomicin is typically more expensive still. In practice, the choice between the two often depends on insurance coverage, recurrence history, and the severity of the infection.
Treating Recurrent Infections
When C. diff comes back after an initial course of vancomycin, a simple repeat of the same 10-day regimen isn’t the best approach. Instead, guidelines recommend a tapered and pulsed regimen. This means starting with the standard four-times-daily dose for about 10 to 14 days, then gradually reducing the frequency: twice daily for a week, once daily for a week, then once every two or three days for several more weeks.
The logic behind tapering is that C. diff can form spores that survive the initial treatment. By spacing out doses over a longer period, the antibiotic catches newly emerging bacteria as spores germinate, rather than leaving a gap where they can re-establish the infection. Studies show that taper-and-pulse regimens produce better outcomes than pulse-only schedules, with success rates ranging from 58% to 100% depending on the specific protocol used.
For patients with multiple recurrences, fidaxomicin or newer therapies like fecal microbiota transplantation are often considered alongside or instead of vancomycin.
Fulminant C. Diff Infections
In the most dangerous cases, known as fulminant C. diff, the infection causes life-threatening complications such as extremely low blood pressure, organ dysfunction, or a condition where the colon stops moving entirely (paralytic ileus). For these patients, vancomycin is still central to treatment but is combined with other approaches. Guidelines recommend adding intravenous metronidazole, because when the colon is severely inflamed, metronidazole given through the bloodstream can penetrate the damaged intestinal wall and reach the infection from the other side.
If the gut has shut down and oral medication can’t reach the lower colon, vancomycin can also be delivered rectally as an enema. The evidence supporting rectal vancomycin is limited, but it’s used as an additional measure when other routes may not be getting the drug where it needs to go.
Side Effects of Oral Vancomycin
Because oral vancomycin stays mostly in the digestive tract and isn’t well absorbed into the bloodstream, it tends to cause fewer systemic side effects than many other antibiotics. The most common issues are gastrointestinal: abdominal pain, nausea, and an altered sense of taste. Less common side effects include headache, fatigue, swelling in the hands or feet, vomiting, and flatulence.
Serious side effects are rare with oral use but not impossible. There have been reports of kidney damage, particularly in patients over 65. Hearing problems, including ringing in the ears and hearing loss, have also been documented in rare cases. These risks are more commonly associated with intravenous vancomycin at high doses, but they can occur with oral use as well, especially in patients taking other medications that stress the kidneys or ears.
Cost and Access Challenges
Generic vancomycin capsules have been available since 2012, but pricing in the United States remains surprisingly high. A standard 10-day course frequently costs several hundred dollars out of pocket and can exceed $1,000, with inconsistent insurance coverage. For comparison, the same course costs around $207 in Canada, suggesting the high U.S. price isn’t driven by manufacturing costs.
Many pharmacies work around the cost problem by compounding an oral liquid from the much cheaper intravenous formulation of vancomycin. This liquid version is functionally the same drug delivered to the same place, but because it isn’t FDA-approved as an oral product, insurers sometimes won’t cover it either. If cost is a concern, it’s worth asking your pharmacy about the compounded liquid option, which can be substantially less expensive than capsules.