CDI Treatment: What Works Best and When

If you or someone you know has caught Clostridioides difficile (C. diff), the first thing you want is relief. The infection causes watery diarrhea, belly cramps and sometimes fever. Good news: most cases clear up with the right medicines and a few extra steps.

First‑line options

The go‑to drugs for CDI are oral vancomycin and fidaxomicin. Vancomycin comes in 125 mg capsules taken four times a day for ten days. It stays inside the gut where the bug lives, so it works well without many side effects.

Fidaxomicin is newer and pricier, but it cuts down repeat infections. The usual dose is 200 mg twice daily for ten days. If cost isn’t a barrier, many doctors prefer it because it spares more of the normal gut bacteria.

A short course of metronidazole used to be popular, but guidelines now push it to mild cases only. It’s taken as 500 mg three times a day for ten days and works best when the infection hasn’t spread far.

When standard therapy fails

About 20‑30% of people get another bout after finishing antibiotics. If symptoms return within two weeks, doctors call it a recurrence. The first step is to repeat the same antibiotic, but many turn to a tapered‑and‑pulse vancomycin regimen – start with full dose, then slowly lower it over several weeks.

For stubborn cases, fecal microbiota transplantation (FMT) is a game changer. It involves putting screened donor stool into the patient’s colon through an enema, capsule or colonoscopy. Studies show cure rates above 90% for multiple recurrences. The procedure sounds scary, but it simply restores healthy bacteria that push C. diff out.

Probiotic supplements can help keep the gut balanced after antibiotics, though they aren’t a stand‑alone cure. Look for strains like Saccharomyces boulardii or Lactobacillus rhamnosus, and take them for at least two weeks post‑treatment.

Finally, keep an eye on infection control. Hand washing with soap (not just alcohol) is key because C. diff spores survive on surfaces. If you’re in a hospital or nursing home, ask staff about proper cleaning protocols.

Putting it all together: start with vancomycin or fidaxomicin, repeat the course if symptoms bounce back, consider tapered dosing, and don’t shy away from FMT for repeated relapses. Add a probiotic, stay hydrated, and practice strict hygiene. Most people feel better within a week, and with the right steps you can keep the infection from coming back.