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- Metronidazole vs. ketoconazole: What's the difference?
- What is metronidazole? What is ketoconazole?
- What are the side effects of metronidazole and ketoconazole?
- What is the dosage for metronidazole and ketoconazole?
- What drugs interact with metronidazole and ketoconazole?
- Are metronidazole and ketoconazole safe to use while pregnant or breastfeeding?
Metronidazole vs. ketoconazole: What's the difference?
- Metronidazole and ketoconazole are used to treat different kinds of infections.
- Metronidazole is used to treat parasitic infections including Giardia infections of the small intestine, amebic liver abscess, amebic dysentery, bacterial vaginosis, trichomonas vaginal infections, and carriers of trichomonas who do not have symptoms of infection; to treat abscesses in the liver, pelvis, abdomen, and brain; to treat infection of the colon caused C. difficile (C. diff); and Helicobacter pylori (H. pylori) that causes stomach or intestinal ulcers. Metronidazole topical gel is used for treating acne rosacea and metronidazole vaginal gel is used for treating bacterial vaginosis.
- Ketoconazole is used to treat fungal infections such thrush, ringworm, jock itch, athlete's foot, dandruff, tinea versicolor, blastomycosis, histoplasmosis, and coccidiomycosis.
- Metronidazole and ketoconazole belong to different drug classes. Metronidazole is an antibiotic and ketoconazole is an azole antifungal.
- Brand names of Metronidazole include Flagyl and Flagyl ER.
- Brand names of ketoconazole include Nizoral, Nizoral A-D, Ketodan, Extina, Xolegel, and Kuric.
- Side effects of metronidazole and ketoconazole that are similar include nausea, vomiting, headaches, abdominal cramps or pain, dizziness, and rash.
- Side effects of metronidazole that are different from ketoconazole include loss of appetite, metallic taste in mouth, diarrhea, dry mouth, dark-colored urine, weight loss, constipation, furry tongue, nasal congestion, flushing, and vaginal dryness.
- Side effects of ketoconazole that are different from metronidazole include itching, fatigue, impotence, and blood count abnormalities.
What is metronidazole? What is ketoconazole?
Metronidazole is an antibiotic 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; to treat abscesses in the liver, pelvis, abdomen, and brain; to treat infection of the colon caused C. difficile (C. diff); and Helicobacter pylori (H. pylori) that causes stomach or intestinal ulcers. Metronidazole topical gel is used for treating acne rosacea and metronidazole vaginal gel is used for treating bacterial vaginosis. Metronidazole selectively blocks some of the functions within the bacterial cells and the parasites resulting in their death.
Ketoconazole is an azole antifungal medication used to treat fungal infections such thrush, ringworm, jock itch, athlete's foot, dandruff, tinea versicolor, blastomycosis, histoplasmosis, and coccidiomycosis. Ketoconazole is in the same family of drugs as fluconazole (Diflucan), itraconazole (Sporanox), and miconazole (Micatin, Monistat). It prevents growth of several types of fungi by preventing production of the membranes that surround fungal cells.
What are the side effects of metronidazole and ketoconazole?
Common side effects are:
- Skin irritation
- Skin dryness
- Allergic contact dermatitis
- Burning and stinging
- Allergic reaction
- Candida vaginitis during or shortly after therapy
- Vaginal vulvar itching
- Gastrointestinal cramps or pain
- Metallic taste
Other important side effects include:
Ketoconazole generally is well tolerated. Commonly reported side effects of ketoconazole are:
- abdominal pain,
- impotence, and
- blood count abnormalities.
Other important side effects of ketoconazole are rare; they include:
Liver dysfunction also has been reported. Signs of liver problems include unusual fatigue, loss of appetite, nausea and vomiting, yellowing of the skin (jaundice), dark urine, and pale stools. Development of these symptoms while taking ketoconazole should be reported to a physician.
What is the dosage for metronidazole and ketoconazole?
The usual dose of vaginal metronidazole gel is one applicator full (containing 37.5mg of metronidazole) intravaginally twice daily for five days. It should be applied once in the morning and once in the evening.
Ketoconazole may be taken with or without food. The oral dose range is 200-400 mg daily. Recurrent tinea versicolor is treated with 400 mg monthly. Topical formulations are administered to affected areas once or twice daily.
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What drugs interact with metronidazole and ketoconazole?
Alcoholic beverages should not be consumed while being treated with metronidazole vaginal gel since this may result in:
This is the same reaction (disulfiram reaction) that occurs in alcoholics who drink alcohol while taking disulfiram (Antabuse), a drug used to discourage alcoholics from drinking alcohol.
Oral metronidazole interacts with warfarin (Coumadin), increasing the latter's blood-thinning properties. Little metronidazole is absorbed topically or from the vagina, and it is not known if the low blood levels achieved with topical or vaginal metronidazole can result in this interaction.
If your doctor has prescribed this medication, your doctor or pharmacist may already know of any possible drug interactions and may be watching out for them. Check with your doctor, health care professional or pharmacist before starting, stoping, or changing the dosage of any medicine.
- severe interactions with at least 33 different drugs
- serious interactions with at least 202 different drugs
- moderate interactions with at least 241 different drugs
- mild interactions with at least 105 different drugs
This information does not contain all possible drug interactions or adverse effects. Therefore, before using this product, tell your doctor or pharmacist of all the medications and supplements you use. Keep a list of all your medications with you, and share this information with your doctor and pharmacist. Contact your health care professional or doctor for additional medical advice, or if you have health questions, concerns or for more information about this medicine.
Are metronidazole and ketoconazole safe to use while pregnant or breastfeeding?
Animal studies have not demonstrated a risk to the fetus, but there are no adequate studies in pregnant women.
Orally administered metronidazole is secreted in human milk in concentrations that are similar to concentrations in the mother's blood. Although metronidazole concentration in blood after vaginal or topical administration is small, potential effects on the infant still should be considered.
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Related Disease Conditions
Bacterial Vaginosis (BV)
Bacterial vaginosis is an abnormal vaginal condition with signs and symptoms of vaginal discharge, vaginal odor, and vaginal pain. Bacterial vaginosis results from an overgrowth of normal bacteria in the vagina. Although it may cause some disturbing symptoms (discharge and odor), it is not dangerous and cannot be passed by sex. Diagnosis becomes important to exclude serious infections like gonorrhea and Chlamydia. Many treatment options are available such as oral antibiotics and vaginal gels.
The term "ringworm" refers to a fungal infection on the surface of the skin. A physical examination of the affected skin, evaluation of skin scrapings under the microscope, and culture tests can help doctors make the appropriate distinctions. A proper diagnosis is essential to successful treatment. The different types of ringworm include the following: tinea barbae, tinea capitis, tinea corporis, tinea cruris, tinea faciei, tinea manus, tinea pedis, and tinea unguium.
Is Ringworm Contagious?
A fungus causes ringworm. Ringworm can be transmitted from person to person. Animals may also spread ringworm. Ringworm causes an itchy, ring-shaped red rash with hair loss. Treatment incorporates the use of topical medication.
Eczema is a general term for many types dermatitis (skin inflammation). Atopic dermatitis is the most common of the many types of eczema. Other types of eczema include: contact eczema, allergic contact eczema, seborrheic eczema, nummular eczema, stasis dermatitis, and dyshidrotic eczema.
Giardiasis (Giardia lamblia) is a parasite responsible for a common form of infectious diarrhea. The parasite lives in two stages: trophozoites and cysts. People at risk for giardiasis are those that live in areas where there is inadequate sanitation or treatment of drinking water. Giardiasis also is a common cause of outbreaks of diarrhea in day-care centers. Symptoms and signs of giardiasis include abdominal pain, stomach cramping, bloating, nausea, and fatigue. Treatment for giardiasis is with antibiotic medication.
Seborrheic dermatitis is a chronic skin condition. Symptoms and signs include a red, scaling rash on the scalp, face, ears, and torso. Treatment often includes the use of a medicated shampoo and the application of a topical steroid lotion.
SIBO (Small Intestinal Bacterial Overgrowth)
Small intestinal bacterial overgrowth (SIBO) refers to a condition in which abnormally large numbers of bacteria (at least 100,000 bacteria per ml of fluid) are present in the small intestine, but they are more like the bacteria that are found in the colon. There are many conditions associated with SIBO, including: Diabetes Scleroderma Crohn's disease Irritable bowel syndrome (IBS) It has been theorized that SIBO may be responsible for the symptoms of at least some patients with irritable bowel syndrome. Symptoms of SIBO include: Excess gas Abdominal bloating Abdominal pain Treatment for SIBO can include: Antibiotics Probiotics Low FODMAP Diet
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.
Is C. diff (Clostridium difficile) Contagious?
C. diff, or Clostridium difficile, is a bacteria that infects the colon. C. diff bacteria can be found on furniture, bathroom floors, telephones, fingernails, jewelry, toilet seats, and other places. Symptoms of C. diff infection are fever, abdominal pain, and cramps; however, not all people infected with C. diff have symptoms. Treatments for C. diff are antibiotics and surgery in some cases.
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.
Nontuberculous Mycobacterial Lung Disease (NTM, Symptoms, Treatment, Side Effects)
Nontuberculous mycobacteria (NTM), most commonly, M. avium complex or MAC, is a mycobacteria that causes lung infections and disease. Nontuberculous mycobacteria are commonly found in soil, air, and water. Examples of how NTM lung infection are transmitted include swimming, using a hot tub (NTM bacteria are aerosolized), or playing with or handling soil. The most common symptoms of NTM lung infection are chronic, dry cough, and shortness of breath. Sometimes the cough may have mucous or blood. Other symptoms of NTM lung disease include fatigue, chest pain, malaise, and weakness. As NTM lung disease progresses, fevers, night sweats, and appetite loss may occur. Treatment guidelines for NTM lung disease depend upon the type and extent of the infection, and the person's health.
Treatment & Diagnosis
Medications & Supplements
- metronidazole (Flagyl, Flagyl ER) Antibiotic
- metronidazole - oral, Flagyl
- ketoconazole shampoo - topical, Nizoral
- ketoconazole cream - topical, Nizoral
- ketoconazole - oral, Nizoral
- metronidazole - injection, Flagyl, Metro
- Flagyl (metronidazole) Side Effects, Warnings, and Interactions
- ketoconazole, Nizoral, Extina, Xolegel, Kuric
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