Find patient medical information for Metronidazole Oral on WebMD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. The most common side effects of metronidazole tablets, liquid, suppositories or vaginal gel are feeling or being sick, diarrhoea, and a slight metallic taste in your mouth. Learn about Flagyl (Metronidazole) may treat, uses, dosage, side effects, drug interactions, warnings, patient labeling, reviews, and related medications. Metronidazole is the generic form of the brand name drug Flagyl, which is used to treat bacterial infections of the skin, vagina, stomach, joints, or respiratory tract. Metronidazole is a synthetic (man-made) drug that is effective against certain bacteria and parasites (protozoa). The topical forms (gels, creams, and lotions) of metronidazole are used for treating vaginal infections with protozoa such as Trichomonas vaginalis, amoeba, and Giardia. Metronidazole is a prescription drug used to treat infections caused by bacteria or other parasites in different parts of your body. It works by destroying the germs that cause infection. The drug. Flagyl (metronidazole) is an antibiotic prescribed to treat various parasitic and bacterial infections (Giardia, C. diff, H. pylori). Common side effects are headaches, nausea, and metallic taste in the mouth. Pregnancy and breastfeeding safety information are provided. Interactions between your selected drugs Moderate ethanol metronidazole Applies to: Alcohol (contained in alcoholic beverages) (ethanol), MetroGel-Vaginal (metronidazole topical) What other drugs will affect metronidazole? Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective. Metronidazole is used to treat a certain type of vaginal infection (bacterial vaginosis) in women who are not pregnant. Learn about side effects, drug interactions, dosages, warnings, and more.