Uses
Flagyl is sometimes used to treat Crohn’s disease, which is one form of inflammatory bowel disease (IBD), especially when the disease is affecting the perianal area or only the colon (large intestine). It may also be used to treat pouchitis, which is a poorly-understood condition that occurs in people who have had surgery to remove their large intestine and create an internal pouch from the small intestine, which is called a j-pouch. Pouchitis tends to occur more often in people who had the surgery to treat ulcerative colitis than in people who had the surgery to treat another condition in the colon, such as familial adenomatous polyposis (FAP).
Flagyl is also used to treat an infection in the digestive tract with a bacteria called Clostridioides difficile (formerly called Clostridium difficile, commonly called C. diff). C. diff infections are becoming increasingly prevalent and are especially dangerous when they occur in people who have IBD. For treating pouchitis and C. diff, Flagyl is sometimes taken for long periods of time, and perhaps along with another antibiotic, or alternating with another antibiotic.
Flagyl is also used in combination with other drugs to treat an infection with Helicobacter pylori. H. pylori infects the stomach and can lead to stomach ulcers.
Common Side Effects
Check with your healthcare provider if any of the following side effects continue or are bothersome:
diarrheadizziness or light-headednessheadacheloss of appetitenausea or vomitingstomach pain or crampsunpleasant or sharp metallic taste
Check With Your Healthcare Provider
Check with your healthcare provider if you have any of the following side effects, which may be caused by hypersensitivity to the medication:
any vaginal irritation, discharge, or dryness not present before use of this medicinedryness of the mouthclumsiness or unsteadinessmood or other mental changesskin rash, hives, redness, or itchingsore throat and feverstomach and back pain (severe)
For injection form:
Pain, tenderness, redness, or swelling over the vein in which the medicine is given
Other Important Considerations
All antibiotics can reduce the effectiveness of oral contraceptives (“the pill”), so women using this as their birth control method should use a backup method until after finishing the course of antibiotics.
Less common: Numbness, tingling, pain, or weakness in hands or feet
Rare: Convulsions (seizures)
Flagyl can also sometimes cause urine to turn dark brown, but this is not dangerous and it goes away after the drug is stopped.
Other side effects not listed above may also occur in some patients. Check with a healthcare provider about any other effects that occur. This information is meant only as a guideline—always consult a healthcare provider or pharmacist for complete information about prescription medications.
