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What is Metronidazole 500mg Used for

Bacterial infections are treated with antibiotics. The following article provides information on the use of metronidazole in human beings as well as in dogs. Read on, to know more about the side effects and dosage of the antibiotic....
Leena Palande
Metronidazole is an antibiotic which effectively protects you from health problems caused by anaerobic bacteria and certain parasites. Anaerobic bacteria, the single-celled organism, can grow vigorously even in an environment where very little oxygen is available. They can cause abdominal diseases (like bacterial peritonitis), liver diseases (like liver abscess), and pelvis disorders (like abscess of the ovaries and the fallopian tubes). For instance, Giardia lamblia and amoeba are the common intestinal parasites that can cause abdominal pain and diarrhea in infected individuals. A vaginal parasite known as Trichomonas is responsible for inflammation of the vagina (vaginitis). Metronidazole 500mg tablets help block some of the functions of the bacterial cells and the cell functions of parasites, leading to their death.
Metronidazole Uses
Metronidazole is the generic name of the medicine. In the U.S., medicines containing this antibiotic are available under the brand name Flagyl, Metro, Flagyl IV, Flagyl ER. 500mg tablets of this medicine are commonly used to treat:
  • Parasitic infections including 'Giardia infections' of the small intestine
  • Amoebic liver abscess
  • Amoebic dysentery (severe infection of the colon resulting in bloody diarrhea)
  • Meningitis
  • Skin infection
  • Pneumonia
  • Dental abscess
  • Bacterial vaginosis
  • Abscesses in the pelvis, abdomen and brain caused by susceptible anaerobic bacteria
  • Infection of the colon caused by a bacterium called C. difficile.
  • Crohn's disease
  • Trichomonas vaginalis
  • Carriers of Trichomonas that do not exhibit any symptoms of the infection
  • Pelvic Inflammatory Disease
  • Diverticulitis
  • Helicobacter pylori infection that causes stomach or intestinal ulcers
Availability in Various Forms
Metronidazole tablets are available in various preparations such as 250 mg, 500 mg, 750 mg. Apart from these, 375 mg capsules are also available. Cream and gel have 0.75% and 1% metronidazole, while the lotion contains 0.75%. Injections with 5 mg/ml of metronidazole are sometimes used. Cream or gel containing this antibiotic is used to treat acne rosacea. The vaginal gel is used to treat bacterial vaginosis. For giardia, 250 mg tablets are recommended, three times daily, for 5 days. The following table explains the uses of metronidazole more clearly.
Name of the Disease Metronidazole Dosage
Amoebic dysentery 750 mg orally, daily 3 times for 5 - 10 days
Amoebic liver abscess 500 - 750 mg orally, daily 3 times for 5 - 10 days
Anaerobic infections 7.5 mg/kg orally, every 6 hours, not to exceed 4 grams daily
Bacterial Vaginosis (tablet) 750 mg orally, once daily for 7 days
Bacterial Vaginosis (gel) 0.75% vaginal gel, apply it once or twice daily for 5 days
Clostridium difficile infection 250 - 500 mg orally, daily 4 times for 5 - 10 days / 500 - 750 orally, daily 3 times for 5-10 days
Giardia infection 250 mg orally, daily 3 times for 5 days
Helicobacter pylori infection 800 - 1500 mg orally, daily for several days in combination with other drugs
Pelvic inflammatory disease (PID) 500 mg orally, daily twice for 14 days in combination with other drugs
Trichomoniasis 2g single dose or 1 g twice, for one day
Rosacea gel 0.75 - 1%, apply topically, once daily
Side Effects
Metronidazole should not be taken by pregnant women and nursing moms. Serious side effects of metronidazole include seizures and nerve damage resulting in numbness and tingling sensation in extremities (peripheral neuropathy). Such severe side effects are rarely observed but minor side effects like nausea, headache, loss of appetite, metallic taste, and skin rash can be sometimes experienced by the person. While on metronidazole, alcohol should be strictly avoided. Consumption of this antibiotic along with alcohol can lead to severe side effects like increased heart rate, high blood pressure, seizures, liver cirrhosis, breathing difficulty, headache, digestion problems, etc.
Benefits of Metronidazole 500mg Tablets for Dogs and Cats
You need a prescription from your vet if you want to use metronidazole for dogs and cats. Benefits of this medicine for dogs and cats are:
  • The antibiotic works great for inflammatory bowel disease.
  • It lowers the symptoms of infections, including those caused by Giardia, the intestinal parasite. Such infections often lead to diarrhea.
  • It also works great for periodontal diseases.
This antibiotic treats a wide array of ailments in dogs and cats. Usually, a dose of 3 mg to 23 mg per pound is given to dogs, one to four times a day. The recommended dose of metronidazole for cats is 5 mg to 23 mg per pound, once or twice a day. So if you are thinking of giving this medicine to your dog, then you should first check the weight of your dog and then calculate the dose accordingly. To dogs weighing low, 250 mg can be given to treat bowel infection.
The dose and duration of the treatment may vary according to the specific condition being treated. And remember, you should give metronidazole to your pet, for the entire length of time, prescribed by your veterinarian. Some pets may be allergic to this antibiotic, so check for the allergy before giving the dose. Overdose of the medicine may cause nausea, vomiting, dizziness, loss of balance or coordination, or seizures. So, you are expected to follow the instructions religiously.
Disclaimer: The information presented in this article is meant to provide guidelines and should not be treated as a medical advice. You should consult your doctor for any of the problems mentioned above.