- Side Effects
- Drug Interactions
- Pregnancy & Breastfeeding
- What Else to Know
Generic Name: metronidazole
Brand Names: Flagyl, Flagyl ER, Metro IV (discontinued), Metromidol (discontinued), Protostat (discontinued), and Satric (discontinued)
Drug Class: Nitroimidazoles
What is metronidazole, and what is it used for?
Metronidazole is an antibiotic effective against anaerobic bacteria and certain parasites. Anaerobic bacteria are single-celled, living organisms that thrive in environments in which there is little oxygen (anaerobic environments). Anaerobic bacteria can cause disease in the abdomen (bacterial peritonitis), liver (liver abscess), and pelvis (abscess of the ovaries and the Fallopian tubes).
Giardia lamblia and ameba are intestinal parasites that can cause abdominal pain and diarrhea in infected individuals. Trichomonas is a vaginal parasite that causes inflammation of the vagina (vaginitis). Metronidazole selectively blocks some of the functions within the bacterial cells and the parasites resulting in their death.
- Metronidazole is used to treat parasitic infections including Giardia infections of the small intestine, amebic liver abscess, and amebic dysentery (infection of the colon causing bloody diarrhea), bacterial vaginosis, trichomonas vaginal infections, and carriers of trichomonas (both sexual partners) who do not have symptoms of infection.
- Metronidazole is also used alone or in combination with other antibiotics in treating abscesses in the liver, pelvis, abdomen, and brain caused by susceptible anaerobic bacteria.
- Metronidazole is also used in treating infection of the colon caused by a bacterium called C. difficile. Many commonly-used antibiotics can alter the type of bacteria that inhabit the colon. C. difficile is an anaerobic bacterium that can infect the colon when the normal types of bacteria in the colon are inhibited by common antibiotics. This leads to inflammation of the colon (pseudomembranous colitis) with severe diarrhea and abdominal pain.)
- Metronidazole also is used in combination with other drugs to treat Helicobacter pylori (H. pylori), which causes stomach or intestinal ulcers.
- Metronidazole topical gel is used for treating acne rosacea.
- Metronidazole vaginal gel is used for treating bacterial vaginosis.
What are the side effects of metronidazole?
Metronidazole is a useful antibiotic and is generally well tolerated with appropriate use.
The most common and minor side effects include:
- Loss of appetite
- A metallic taste
- Rarely a rash
- Abdominal cramps
- Dry mouth
- Dark-colored urine
- Metallic taste in mouth
- Weight loss (anorexia)
- Furry tongue
- Nasal congestion
- Vaginal dryness
Side effects that are uncomfortable, but may become serious include:
- Brain disease
- Mouth sores
- Pain with urination
- Prickling or tingling sensations that may become permanent
- Pelvic pain or pressure
- Decrease of libido
Serious side effects of metronidazole are rare and the drug should be stopped if these symptoms appear:
What is the dosage for metronidazole?
- Metronidazole may be taken orally with or without food.
- In the hospital, metronidazole can be administered intravenously to treat serious infections.
- The liver is primarily responsible for eliminating metronidazole from the body, and doses may need to be reduced in patients with liver disease and abnormal liver function.
Various metronidazole regimens are used. Some examples are listed below.
- Amebic dysentery: 750 mg orally 3 times daily for 5-10 days
- Amebic liver abscess: 500-750 mg orally three times daily for 5-10 days
- Anaerobic infections: 7.5 mg/kg orally or by injection every 6 hours for 7 to 10 days not to exceed 4 grams daily.
- Bacterial vaginosis: 750 mg (extended release tablets) once daily for 7 days or 500 mg twice daily for 7 days or 2 g single dose or one applicator-full of 0.75% vaginal gel, once or twice daily for 5 days.
- Clostridium difficile infection: 250-500 mg orally 4 times daily or 500-750 orally 3 times daily
- Giardia: 250 mg orally three times daily for 5 days Helicobacter pylori: 800-1500 mg orally daily for several days in combination with other drugs.
- Pelvic inflammatory disease (PID): 500 mg orally twice daily for 14 days in combination with other drugs.
- Trichomoniasis: 2 g single dose or 1 g twice
- Rosacea: apply topical gel 0.75-1% once daily
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What drugs interact with this medication?
- Alcohol should be avoided because metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache.
- Metronidazole can increase the blood-thinning effects of warfarin and increase the risk of bleeding probably by reducing the breakdown of warfarin.
- Cimetidine (Tagamet) increases blood levels of metronidazole while cholestyramine reduces blood levels of metronidazole by reducing its absorption.
- Metronidazole should not be combined with amprenavir (Agenerase) for treating human immunodeficiency disease (infection with HIV) because amprenavir contains propylene glycol.
- Metronidazole blocks the breakdown of propylene glycol in the liver leading to accumulation of propylene glycol in blood. Accumulation of propylene glycol could cause seizures, increased heart rate, and lead to kidney failure.
- Metronidazole increases the blood levels of carbamazepine (Tegretol, Tegretol XR, Equetro, Carbatrol), lithium (Eskalith, Lithobid) and cyclosporine though unknown mechanisms. Serious reactions may occur if these drugs are taken with metronidazole.
Pregnancy and breastfeeding
What else should I know about metronidazole?
Do I need a prescription for metronidazole?
What preparations of metronidazole are available?
- Tablets: 250 and 500 mg.
- Tablets, extended release: 750 mg.
- Capsule: 375 mg.
- Cream: 0.75% and 1%.
- Lotion: 0.75%.
- Gel: 0.75% and 1%.
- Injection: 5 mg/ml
How should I keep metronidazole stored?
- Metronidazole should be stored at room temperature and protected from light.
When was metronidazole approved by the FDA?
- The FDA approved metronidazole tablets in July 1963.
Metronidazole is a prescription antibiotic medication prescribed for the treatment of a variety of parasitic and bacterial infections of the vagina, gynecological area, skin, intra-abdominal cavity, blood, bone, joint, nervous system, and heart. For example, giardia, bacterial vaginosis, pelvic inflammatory disease (PID), C. difficile, H. pylori, STDs (trichomonas), acne rosacea, peritonitis, endometriosis, endomyometritis, tubo-ovarian abscess, bacterial septicemia, meningitis, brain abscess, pneumonia, lung abscess, and endocarditis.
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Is H. pylori Contagious?
H. pylori (Helicobacter pylori) infection: Is it contagious? H. pylori infection is caused by fecal contamination in either food or water, and by poor hygiene practices such as not washing the hands often. Common symptoms of H. pylori are a discomfort or pain in the area of the stomach. Some individuals describe the pain as gnawing or burning. Treatment of H. pylori infection is antibiotic therapy.
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Can a Man Give a Woman Trichomoniasis?
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What Is Crohn's Disease?
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Can You Get Trichomoniasis Without Being Sexually Active?
Trichomoniasis is passed from an infected person to another primarily during sexual activity. In very rare cases, it can be transferred from an infected mother to her unborn child. Any sexual activity during vaginal, oral or anal sex can cause the infection to spread. Even if your partner has no symptoms, they can spread the infection.
Crohn's Disease vs. Ulcerative Colitis (UC)
Crohn's disease and ulcerative colitis are diseases that cause inflammation of part of or the entire digestive tract (GI). Crohn's affects the entire GI tract (from the mouth to the anus), while ulcerative colitis or ulcerative colitis only affects the large and small intestine and ilium. Researchers do not know the exact cause of either disease. About 20% of people with Crohn's disease also have a family member with the disease. Researchers believe that certain factors may play a role in causing UC. Both Crohn's disease and ulcerative colitis are a type of inflammatory bowel disease or IBD. Crohn's disease and ulcerative colitis both have similar symptoms and signs, for example, nausea, loss of appetite, fatigue, weight loss, episodic and/or persistent diarrhea, fever, abdominal pain and cramping, rectal bleeding, bloody stools, joint pain and soreness, eye redness, or pain. Symptoms unique to Crohn’s disease include anemia and skin changes. Symptoms of unique to ulcerative colitis include certain rashes, and an urgency to defecate (have a bowel movement). Doctors diagnose both diseases with similar tests and procedures. While there is no cure for either disease, doctors and other health care professionals can help you treat disease flares, and manage your Crohn's or ulcerative colitis with medication, diet, nutritional supplements, and/or surgery.
H. pylori: Natural Treatments and More
Helicobacter pylori or H. pylori infection occurs when H. pylori bacteria infects the lining of the stomach. H. pylori are responsible for 80% of gastric ulcers and 90% of duodenal ulcers. H. pylori infection can continue throughout life without any symptoms.
Clostridium Difficile Colitis (C. diff, C. difficle Colitis)
Clostridium difficile (C. difficile) is a bacterium, and is one of the most common causes of infection of the colon. C. difficile spores are found frequently in hospitals, nursing homes, extended care facilities, and nurseries for newborn infants.
Chronic Fatigue Syndrome (CFS or SEID)
Chronic fatigue syndrome (CFS) or systemic exertion intolerance disease (SEID) is a debilitating and complex disorder characterized by profound fatigue that lasts 6 months or longer, is not improved by bed rest, and may be worsened by physical or mental activity.
Can Bacterial Vaginosis Clear Up on Its Own?
Learn what medical treatments can ease your bacterial vaginosis symptoms and help you manage this condition.
What Will Happen If H Pylori Goes Untreated?
If left untreated H pylori infection can cause abdominal symptoms, as well as lead to the following complications.
What Are the Symptoms of Trichomoniasis in Females?
Trichomoniasis or Trich is a type of sexually transmitted disease (STD) caused by a parasite, Trichomonas vaginalis. It is the commonest curable STD. The parasite can infect both men and women, however, the infection is more common in women than in men. Trichomoniasis is more common in older women.
How Do You Get Bacterial Vaginosis?
Bacterial vaginosis is a common issue that affects many women. Learn the signs of bacterial vaginosis, what causes it, how doctors diagnose it, and what you can do to treat it.
Yeast Infection vs. Bacterial Vaginosis (BV)
Yeast infections and bacterial vaginosis (BV) both cause vaginal discharge. Yeast infection discharge is thick, white, and had a cottage cheese consistency. BV discharge is whitish-gray and is thinner. Vaginal odor, irritation, and pain may also be present. Treatment of yeast infections includes over-the-counter and prescription antifungals. BV treatment involves antibiotics.
Helicobacter Pylori (H Pylori) Infection Causes
Helicobacter pylori (H pylori) is a bacterium that is present in approximately half of the people in the world. However, not everybody infected with H pylori develops the signs and symptoms of the H pylori infection.
Is Diverticulitis Contagious?
Diverticulitis is an inflammation of the diverticula or diverticulum. Diverticulitis causes are either infectious or noninfectious, however, it is not contagoius. Symptoms of diverticulitis include: nausea, vomiting, diarrhea, gas, constipation, changes in bowel habits, bloating, constipation, fever, abdominal tenderness, swollen abdomen, fistula formation, and lower left abdominal pain.
Treatment & Diagnosis
- Penile Discharge
- Vaginal Discharge
- Abscessed Tooth
- Helicobacter pylori (H. pylori) Infection
- Bacterial Vaginosis
- Giardiasis (Giardia Lamblia Infection)
- Pelvic Pain
- Pelvic Inflammatory Disease (PID)
- Amebiasis (Entamoeba histolytica Infection)
- Crohn's Disease
- Small Intestinal Bacterial Overgrowth (SIBO)
- C. difficile Colitis
- Doctor: Checklist to Take To Your Doctor's Appointment
- Inflammatory Bowel Disease
- Chronic Fatigue FAQs
- Acne FAQs
- Crohn's Disease FAQs
- Pelvic Inflammatory Disease (PID) FAQs
- Indications for Drugs: Approved vs. Non-approved
- Drugs: The Most Common Medication Errors
- Medication Disposal
- Dangers of Mixing Medications
- Pregnancy Planning - Vaginal Infection Can Cause Premature Birth
- How To Reduce Your Medication Costs
- Pharmacy Visit, How To Get The Most Out of Your Visit
- What is Bacterial Vaginosis?
- Drugs: Buying Prescription Drugs Online Safely
- Can H. Pylori Ulcer Pain Continue After Treatment?
- What Are the Side Effects of Taking Antibiotics Long-Term?
- Antibiotics 101
- Bacterial Vaginosis Treatment
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- Cipro vs. Flagyl
- Flagyl (metronidazole) Side Effects, Warnings, and Interactions
- Metronidazole (Flagyl) vs. Fluconazole (Diflucan)
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- Metronidazole vs. Miconazole
- Metronidazole: Topical (Metrogel, Metrocream, Metrogel Vaginal, and Others)
- Metronidazole (Flagyl) vs. Clindamycin (Cleocin)
- Metronidazole vs. Vancomycin
- Metronidazole vs. Ketoconazole
- What Is Intravenous-to-Oral Switch Therapy?
- Side Effects of Vancomycin Injection
- Metronidazole (Flagyl) vs. azelaic acid (Finacea)
- Helidac (bismuth subsalicylate/metronidazole/tetracycline hydrochloride)
Prevention & Wellness
- Prescription Meds: Too Common in Pregnancy?
- Once-Daily Ivermectin Is a Safe Rosacea Treatment
- Combination Antibiotic Zerbaxa Approved
- New Antibiotic in the Works for Dangerous C. Diff
- C. diff Infections in Hospitals Are Leveling Off
- C. diff on the Rise Outside the Hospital
- New C. diff Drug OK'd by FDA Panel
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