Metronidazole

What is Metronidazole?

Metronidazole is an antibiotic used to treat various infections that can cause diarrhea. These infections can be caused by bacteria or a type of parasites called protozoa. However, metronidazole isn’t used to treat food poisoning or other types of infections like viral gastroenteritis, which can also cause diarrhea but don’t require antibiotics.

If your stools are watery or contain blood or mucus, or if you have a fever, these may be signs of an infection. In this case, metronidazole can help treat the infection, but it’s important to talk to a physician, establish the cause of your symptoms, and get the right treatment.

How does Metronidazole work?

Metronidazole works by killing a type of bacteria called anaerobic bacteria, like Clostridium difficile. They’re called anaerobic because they don’t need oxygen to survive, and can be found for instance in the digestive tract.

To be more specific, metronidazole works as a protein synthesis inhibitor by causing bacterial DNA to break. This means that the bacteria are no longer able to make the proteins they need to survive.^[1]

What doses of Metronidazole are there?

Metronidazole is available as 250mg and 500mg tablets (although we only supply the 500mg ones). Your doctor will tell you how much to take based on your specific needs, but you’ll typically be advised to take the 500mg tablets twice a day for seven days.

Metronidazole is also available as topical cream and vaginal gel. These forms of the drug, however, are used to treat other conditions like rosacea and bacterial vaginosis.

How to take Metronidazole for diarrhea

Generally, you should take your tablets with a glass of water, after eating some food.
Your doctor will prescribe how to take your treatment with Metronidazole depending on the type of infection you have but, typically, you’ll be prescribed 500mg tablets twice a day for seven days.

Does Metronidazole have any side effects?

Most people don’t get any side effects from Metronidazole, but like with any medicine, it can cause them for some people. These shouldn’t last long though, and usually go away as your body gets used to the treatment.

The most common side effects are mild and include feeling sick, vomiting, diarrhea, reduced appetite, headaches, abdominal cramps and constipation. Also, treatment with Metronidazole can also cause a sharp, unpleasant metallic taste in your mouth and a furry tongue. These reactions may be due to an overgrowth of Candida during therapy, as treatment with metronidazole can increase your chance of getting a yeast infection.

More serious side effects, which are very rare, include: seizures, blurry or double vision, severe stomach pain, or yellowing of the skin or eyes. Stop taking the tablets and tell your doctor straight away if you have any of these uncommon but serious side effects.

Another serious side effect is peripheral neuropathy, which can cause symptoms like numbness, tingling, weakness and pain, especially in the hands and feet. But it’s more likely to happen in people who take high doses of Metronidazole or use it for longer than four weeks.^[1]

How long does it take for Metronidazole to work?

Metronidazole is absorbed pretty fast by your body and should start working within one or two hours after you take the tablets. But it might take a few days before you notice an improvement in your symptoms, like diarrhea.

Even if you start feeling better, it’s important to finish the entire course of metronidazole (or any other antibiotic) prescribed by your doctor. The infection may still be there, and it could return if you stop the treatment too early.

What if I make a mistake while taking Metronidazole

Never take more Metronidazole than your doctor has prescribed for you. And if you think you’ve taken more than you should, get in touch with your doctor. If you have any serious side effects, call 911 straight away or go to your nearest emergency department .

If you forgot to take your tablet, take it as soon as you can, unless it’s almost time for your next dose. In that case, just skip it. Never take two doses at once to make up for a missed one, as this can increase the risk of side effects