Metronidazole 250mg is the generic name of an oral antibiotic sold in the United States as Flagyl, which can also be administered as an injection. As with all antibiotics, metronidazole is designed to be used in the treatment of certain types of infections caused by bacteria. It works to kill bacteria and stop them from growing. The medication may be used for several infections, including giardiasis, gastritis, inflammatory bowel disease and balantidiasis, among others. The Mayo Clinic reports that it does not work to fight viruses.
Diarrhea and Nausea
Taking metronidazole 250mg pills---typically, three times per day---can cause some common side effects that are not generally serious. Stools can become loose and watery, resulting in diarrhea. The opposite problem--constipation--may also occur. The drug may cause nausea and vomiting. Combined, these side effects may cause a loss of appetite. Drugs.com states that all of these problems should disappear on their own as your body gets used to metronidazole. If you continue to have these troubles a few days into treatment, tell your physician.
Headaches and Vertigo
Metronidazole 250mg also may induce some problems such as headaches when you first take the pills. You also may experience vertigo or dizziness from the medication. It can throw your balance off and even make you fall down. Lightheadedness is a common and non-serious side effect of metronidazole that will go away on its own.
Taste and Urination
Other non-serious and common side effects that may occur as you first take metronidazole include a metallic taste in the mouth, and a brownish-red or dark urine, according to the National Institutes of Health. In addition, the feet and hands may tingle or feel numb when you first take the drug.
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