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Flagyl and Ear Infections

Ear infections are not uncommon, especially in children. While you absolutely should not try self-treatment for an ear infection, many people want to find out about their options. This is not the worst approach as long as you address your findings and concerns at your doctor’s office.

Flagyl is a commonly used antibiotic of the nitroimidazole group. It is effective against some parasites and certain anaerobic bacteria. Can Flagyl treat an ear infection? Let us put it this way: it is not a first-choice line of treatment. There is some clinical interest in the topic but the research is very limited, and there are tried-and-true medications to treat the problem quickly and efficiently.

Want to know more? Please, continue reading!

What is an Ear Infection

An ear infection is a health issue that occurs when a pathogen starts growing inside the ear. It can be called otitis but this term may also mark non-infectious ear inflammations.

Ear infections are classified according to the part of the ear where they develop.

Otitis Externa

Otitis extrema affects the pinna— the visible part of the ear also called the auricle or outer ear. Usually, it occurs after water stays trapped inside the auricle for a long enough time so that pathogens start to grow in this warm and moist medium.

People who often swim are especially prone to this condition which is why otitis externa is also called “Swimmer’s ear”.

Otitis Media

The middle ear hosts three little bones called ossicles: stapes, malleus, and incus. They pass the sound wave from the eardrum further to the inner ear. It is also a location of the Eustachian tube that balances the air pressure inside the air.

Otitis media, as the name suggests, is the outbreak of an infection/inflammation in the middle ear.

Otitis Interna

The inner ear contains two important formations. The first is a snail-shaped structure known as a cochlea. It has two chambers with fluid and tiny hairs inside. These hairs trap vibrations created by sound waves, convert them into electric signals our brain can recognize, and send them into the brain. As a result, we can hear and identify sounds.

The second structure is a labyrinth, semicircular canals that are also filled with fluid and lined with hair transmitters. They help us maintain balance through this mechanism: during movement, fluid inside the labyrinth sloshes and disturbs hairs, forcing them to send signals through the vestibular nerve. These signals allow the brain to stay informed about the position of the body and control muscles to maintain balance.

The term “otitis interna” means that the lesion of inflammation (either infectious or not) lies in the inner ear. It can affect the labyrinth (also known as labyrinthitis) or the aforementioned vestibular nerve—a health issue referred to as vestibular neuritis.

Common Causes

While inflammations in the ear can occur without pathogens, infections are only caused by harmful microorganisms that get into the suited environment and grow.

Bacterial Infections

The most common bacteria responsible for otitis are Haemophilus influenzae and Streptococcus pneumoniae. Children are especially prone to them. However, other bacterial pathogens can also harm your ears— e.g., as a complication of a respiratory illness. There are also case reports on how bacterial meningitis caused labyrinthitis.

Viral Infections

Viruses that cause flu also result in otitis media. In addition, stomach and herpes viruses can cause an infection in the inner ear.

Fungal infections

When a fungal infection grows in the ear, the condition is called otomycosis. Its most common causative agents are Candida and Aspergillus. Generally, otomycosis starts in the auricle and can grow into the ear canal.

Fungal infections are far less prevalent than bacterial but they still occur.

Risk factors

Some occurrences do not cause ear infections per se but promote their development.

Allergies and common colds

A common cold and allergic reactions have something in common: both can cause congestion and rhinitis. Mucus (thin fluid) produced in the nose can get into the swollen Eustachian tube and accumulate. The heat from the body makes it warm, creating a perfect environment for pathogens.

Water or foreign bodies trapped in the ear

Water, trapped inside the ear, can also serve as a medium for bacteria and viruses. And if there is a foreign body inside the ear canal, or there has been a traumatic event, it can cause an infection.

Ear Infection Symptoms

If something has been trapped in your ear, usually, you will know. The infection, however, becomes noticeable only when it starts causing you discomfort:

  • pain in the ear, especially when lying down;
  • sense of fullness or pressure in the ear;
  • muffled hearing;
  • swelling in the ear, itching, irritation, red blotches;
  • leakage of pus or fluid from the ear canal;
  • fever;
  • dizziness or vertigo (with otitis interna).

In children, trouble sleeping, excessive crying, and tugging at the ear may also signal about ear infection.

Treatments for Ear Infections

We will give a little spoiler here: there are much better options than Flagyl to treat an ear infection.


This is a universally acknowledged fact that bacterial infections are to be treated with antibiotics. However, they are not all-purpose or interchangeable. Antibacterial drugs are divided into classes by their mechanism of action and molecule structure, and each class is effective against certain organisms. For example, metronidazole (the active compound in Flagyl) is actively used to treat parasitic invasions (amebiasis and trichomoniasis), gut infections, and certain severe infectious diseases, such as brain meningitis—but only if they were caused by susceptible pathogens.

The first-choice antibiotic for an ear infection is Amoxicillin (usually, with clavulanic acid to amplify its effect). If the patient is allergic or Amoxicillin is not effective, the healthcare provider may prescribe a drug from the cephalosporine group, such as Cephalexin, or another penicillin, such as doxycycline.

Other Treatments

While AB therapy is a go-to option for bacterial infections, it is not helpful if the infection is viral. In that case, there are additional ways to improve the patient’s condition, although, they are perfectly compatible with antibacterial treatment if necessary.

Warm compresses

A warm compress can help you reduce pain. Use a desiccated heating pad from your local pharmacy, or simply soak a piece of cloth with hot water, drench the excess, and put it to the infected ear for 20 minutes.

OTC pain relievers

Another method to alleviate pain in the ear is OTC medication. The patient can opt for ear drops that contain anti-inflammatory compounds and anesthetics or they can take an NSAID pill, such as acetaminophen or ibuprofen.

Ear irrigation

If there is drainage from your ear, it is likely contaminated with pathogens. You should clean the ear to deprive bacteria of their habitat. However, this procedure should be approved by your doctor because there are contraindications (damaged eardrums, etc.) and possible complications.

Proper sleeping

Sleeping with your infected ear up can ease the pain and pressure inside it. It also allows the fluid inside the ear to drain and dry faster.

How Flagyl Works?

Metronidazole diffuses into the cell, interacts with its proteins, and creates cytotoxic free radicals—highly active particles. These particles stop DNA synthesis in the cell and make DNA strands break. This process results in the death of the cell.

How Flagyl Works for Ear Infections

Metronidazole is effective against anaerobic bacteria, and those thrive in places without oxygen (you have oxygen inside your ears). This is why doctors likely will not prescribe Flagyl for an ear infection.


Doses for metronidazole administration depend on the condition the patient has and its severity. They are to be determined by a healthcare provider, who, should this be necessary, will further adjust them.

Things to remember:

  • The pill, capsule, or tablet should not be chewed, crushed, or broken, as it can alter its metabolism and, thus, efficiency.
  • Strictly follow doctor’s recommendations (time of administration, dose, etc.).
  • Do not drop your medication before the end of the full course even if you already feel better: this will prevent full eradication of the infection, and the disease will reoccur.

Standard treatment programs for metronidazole:

  • Anaerobic infections: 500 mg orally every 6 hours, for 7-10 days or longer.
  • Amebiasis: 500 to 750 mg orally 3 times a day, for 5-10 days.
  • Trichomoniasis (single-day therapy for AFAB patients): 2 grams orally in a single dose or split into two doses to be taken in the morning and in the evening.
  • Trichomoniasis (7-day therapy for AFAB patients): 250 mg per os 3 times per day for 7 days.
  • Bacterial vaginosis (topical administration in cream, gel, vaginal tablet, or suppository): 500 mg vaginally, one or two times a day for 10–20 days.

Flagyl Side Effects

The most common adverse reactions to Flagyl include:

  • headache;
  • dizziness;
  • GI disorders;
  • bad taste in the mouth;
  • allergic reactions;
  • burning when urinating, darker urine color;
  • yeast infections.

Can Flagyl be Used for Ear Infections?

You can stumble on some studies on PubMed and similar resources to conclude that this question has been somewhat studied. However, when treating a patient, their health always comes first. While, theoretically, Flagyl can help treat ear infections (some of them, at least), there are first-line treatment protocols for ear infections with proven efficiency, and many safe and reliable alternatives if necessary.


Ear infections are usually treated with penicillin and cephalosporin antibiotics. Therefore, medical professionals most likely will not use Flagyl for inner ear infections or other kinds of otitis.


What is the best antibiotic for an ear infection?

Amoxicillin with clavulanic acid is a first-choice medication.

What is metronidazole 500 mg used for ear infection?

It is unlikely that metronidazole on any dose will be used to treat otitis.

What is the fastest treatment for ear infection?

Antibiotics are the fastest way to eradicate an infection; your doctor will prescribe it if necessary.

What is the antibiotic of choice for ear infections in adults?

Amoxicillin with clavulanic acid or cephalexin, if the patient is hypersensitive to penicillin.