What is metronidazole used for?

Metronidazole AL 400

Patient information for "Metronidazole"

1. What is "Metronidazole" and what is it used for?

1.1 What are the properties of the medicinal product?

"Metronidazole" contains the active ingredient metronidazole, a drug from the group of so-called antibiotics.

Metronidazole is an agent against protozoa (ancient animals) and anaerobic (without oxygen) bacteria.

Metronidazole requires a prescription and should only be used on medical advice.

1.2 What strengths and dosage forms are there?

Oral metronidazole is usually available as

- Tablets, film-coated tablets or coated tablets containing 250 mg or 400 mg or 500 mg metronidazole.

Your doctor will determine which strength and dosage form are suitable for your treatment.

1.3 Oral metronidazole is used for

- Trichomoniasis: a disease caused by a flagellate, Trichomonas vaginalis. The main inflammation is the vagina and the male urethra. The spread occurs almost exclusively through sexual intercourse. A secretion swab is made to identify the disease.

- Bacterial vaginosis (amine colpitis, unspecific colpitis): In bacterial vaginosis, the bacterial composition that occurs naturally in the vagina is changed. There will be a discharge with a fish-like odor. Amine colpitis and unspecific colpitis are other names for bacterial vaginosis.

- Amebiasis: a disease caused by an ancient root animal, Entamoeba histolytica. Abdominal pain and severe diarrhea usually result from an infection in the gastrointestinal tract. In addition, other organs can be infected, and if left untreated, the disease is often fatal. The stool is examined to detect amoebic dysentery.

- Lambliasis (Giardiasis): a disease caused by a flagellate, Giardia lamblia. An infection in the gastrointestinal tract mainly results in watery diarrhea. Giardia lamblia is found in the stool.

- Infections with involvement of anaerobes, especially infections that originate in the female genitals, gastrointestinal tract, ear, nose and throat and teeth, mouth and jaw area

- Helicobacter pylori infection in the gastrointestinal tract

- infections of the bones and joints

- Skin and soft tissue infections

- Central nervous system infections (including brain abscesses and meningitis), particularly those caused by Bacteroides spp.

Blood poisoning (sepsis)

- endocarditis

- Infection prophylaxis during surgical interventions in the gynecological area or in the gastrointestinal tract.

2. What should you know before you take Metronidazole?

2.1. "Metronidazole" must not be taken

- if you are hypersensitive to metronidazole, other 5-nitroimidazoles or any of the other ingredients of "metronidazole".

There is an exception if there is a life-threatening infection and other drugs are ineffective.

2.2.Special care is required when taking "Metronidazole"

- in the case of severe liver damage, blood formation disorders and diseases of the brain, spinal cord and nerves. Here the treatment must be carefully weighed up by your doctor.

- As with other nitro-imidazole-containing medicinal products, treatment with "metronidazole" must generally not exceed 10 days. This period may only be exceeded in individual cases with particularly strict indications. Appropriate monitoring of the patient (clinical monitoring and laboratory controls) is required The treatment should only be repeated in justified individual cases.

- In trichomoniasis, the sexual partner is often also the carrier of the trichomonads, even if no pathological changes should have been noticed so far. It is therefore necessary in the case of trichomoniasis to also treat the sexual partner with "metronidazole", otherwise reinfection (re-infection) may occur. Therefore, please avoid sexual intercourse during the treatment.

Note on other ingredients: Oral medicinal products may contain different types of sugar. Therefore, please only take this after consulting your doctor if you know that you suffer from an intolerance to certain sugars.

2.2.a) Children

Dosage forms such as film-coated tablets, capsules and coated tablets that have to be swallowed whole are not suitable for children under 6 years of age. The special dosage recommendations for children must be observed (see sections 3. "How should" Metronidazole "be taken?" And 3.2.).

2.2.b) Elderly patients

There are no special precautions.

2.2.c) Pregnancy

The safety of using "metronidazole" during pregnancy has not been sufficiently proven. "Metronidazole" may therefore only be used during pregnancy, especially in the first trimester of pregnancy, only if there is a compelling indication and if other therapeutic options are unsuccessful. Your doctor will decide on the application.

2.2.d) Breastfeeding

The active ingredient from "metronidazole" passes into breast milk. You should therefore interrupt breastfeeding or discontinue the drug and continue breastfeeding if you are receiving therapy during breastfeeding. If you are breastfeeding once, you should stop breastfeeding for 24 hours Time formed milk can be pumped out.

2.2.e) Ability to drive and use machines

"Metronidazole" can impair your ability to react, especially at the beginning of treatment. You will then no longer be able to react quickly and specifically enough to unexpected and sudden events. Do not drive a car or other vehicles! Do not use electrical tools or machines! Do not work without a secure footing! Please note in particular that alcohol makes your ability to drive even worse!

2.3 Which interactions with other medicinal products have to be considered?

Please inform your doctor or pharmacist if you are taking / using or have recently taken / used any other medicines, including medicines obtained without a prescription.

- The administration of the alcohol cessation agent disulfiram can lead to states of confusion and certain mental disorders (psychoses).

- A reduction in the effectiveness of "Metronidazole" occurs when barbiturates (drugs with active ingredients such as hexobarbital or phenobarbital, which are used against sleep disorders and convulsions as well as for anesthesia) and when drugs with phenytoin (active ingredient against convulsions) are given.

- Medicines with cimetidine (active ingredient against gastritis and stomach and intestinal ulcers) can in individual cases impair the excretion of "metronidazole" and thus increase the effect of "metronidazole".

- Patients who are being treated with certain drugs that inhibit blood clotting (anticoagulants of the warfarin type) may have to be readjusted because "metronidazole" increases the anti-coagulant effect of these drugs.

- Caution is advised when administering drugs containing lithium (active ingredient that is given in certain forms of euphoric or depressed mood [manic-depressive states]), because an increase in lithium in the blood was observed afterwards (risk of lithium poisoning with tremors and seizures) .

- Metronidazole can lead to decreased values ​​in some laboratory tests to determine a liver value (determination of the GOT in the serum).

2.4.What should be considered when taking "Metronidazole" together with food, beverages and tobacco?

The consumption of alcohol should be avoided, as otherwise intolerance symptoms can occur, such as reddening of the skin in the area of ​​the head and neck as well as nausea, vomiting, headache and dizziness.

3. How should "Metronidazole" be taken?

Always take "Metronidazole" exactly as your doctor has told you. Please ask your doctor or pharmacist if you are not sure.

3.1 Type and duration of application

"Metronidazole" is swallowed whole with sufficient liquid during or shortly after a meal.

Your doctor will decide on the duration of use.

As with other nitro-imidazole-containing drugs, treatment should generally not exceed 10 days.

3.2 Unless otherwise prescribed by the doctor, the usual dose is

"Metronidazole" is a medicinal product, the amount of which is to be set at very different levels for the individual patient depending on the type and severity of the illness. The daily dose and the duration of intake are determined by your doctor. You must not change either of these without his knowledge.

3.2.a) Children from 6 to 12 years

The daily intake: 20 to 30 mg metronidazole / kg body weight.

0.25 g metronidazole for about 10 kg body weight or e.g. 0.75 g metronidazole for about 30 kg body weight.

3.2.b) Adults and children over 12 years

The daily intake: 0.25 g to 2 g metronidazole. Usually this dose is divided into 2 to 3 divided doses.

3.2.b.1.Uncomplicated infections

In the case of uncomplicated infections (infections that usually heal quickly and without consequences after treatment), a daily dose of 0.5 g metronidazole or less requires treatment for several days (5-7 days).

With a higher intake of 1 g to 2 g metronidazole per day, a short treatment period (1 to 3 days) may be sufficient.

Amine colpitis and trichomoniasis: Adults can also be treated with a single dose of 2 g metronidazole.

3.2.b.2.Complicated infections

In the case of complicated infections (infections that are often difficult to heal even with careful treatment) such as

- endometritis (inflammation of the lining of the womb),

- adnexitis (inflammation of the fallopian tubes or ovaries),

- inflammation of the teeth, mouth and jaw,

- inflammation of the throat, nose and ears,

- Peritonitis (inflammation of the peritoneum) and

- abscesses (pus) in the abdomen

the daily intake is 1.5 g to 2 g metronidazole at the beginning and 1 g metronidazole for 5-7 days on the following days. Only in exceptional cases should the intake amount be increased to 1.5 g metronidazole per day.

Preventive treatment should be limited to a single dose of 0.5 g to 2 g metronidazole.

3.2.b.3.In the case of infection with Helicobacter pylori in the gastrointestinal area

If infection with Helicobacter pylori in the upper gastrointestinal area and the formation of a stomach or intestinal ulcer (ulcer) have been found, antibiotic combination therapy is required to eradicate this germ.

The following therapy combinations are possible, for example:

500 mg metronidazole 3 times a day plus 750 mg amoxicillin 3 times a day and 300 mg ranitidine once a day at bedtime for 10 to 12 days. If a gastrointestinal ulcer is present, treatment with ranitidine 300 mg once daily for 4 weeks can be continued for further healing.

Alternatively, the following combination ("Italian triple therapy") can be used: 500 mg metronidazole twice a day plus 250 mg clarithromycin twice a day and a proton pump inhibitor in a standard dose for 7 days.

3.3. If you take more Metronidazole than you should

If you accidentally take a single dose of "Metronidazole" twice, this has no effect on further intake, i.e. you take "Metronidazole" afterwards as you normally would.

If the drug is taken in excessively high amounts, nausea, vomiting, increased reflexes, ataxia (disturbance in the orderly sequence of movements), accelerated heartbeat, shortness of breath and disorientation (ignorance of time and place) can occur.

No antidote is known. After medical treatment of the symptoms, a complete recovery can be expected after a few days.

3.4.If you forget to take "Metronidazole"

If you notice your mistake on the same day, take the insufficient amount of medicine you have taken on the same day later. If you don't notice your mistake until the next day, it may be necessary to extend the treatment by one day. In such a case, please speak to your doctor.

3.5.Effects when treatment with "Metronidazole" is stopped

If you end the treatment prematurely or interrupt it temporarily, you endanger the success of the treatment! In the event of unpleasant side effects, your doctor will discuss with you what countermeasures are available and whether other medicines are suitable for you.

4. What are the possible side effects?

Like all medicines, "Metronidazole" can cause side effects, although not everybody gets them.

When evaluating side effects, the following frequencies are used as a basis:

- very common: more than 1 in 10 people

- common: less than 1 in 10, but more than 1 in 100 patients

- uncommon: less than 1 in 100 but more than 1 in 1,000 patients

- rarely: less than 1 in 1,000 but more than 1 in 10,000 people treated

- very rare: less than 1 in 10,000 patients, including isolated cases

- Frequency not known: frequency cannot be calculated from the available data

4.1 Which side effects can occur in detail?

4.1.a) Significant side effects or signs to look out for and actions to be taken if affected

If you are affected by any of the side effects listed below, stop taking "Metronidazole" and contact your doctor as soon as possible.

4.1.a.1.Very rare

Anaphylactic shock (a sharp drop in blood pressure indicating hypersensitivity). In severe but very rare cases of hypersensitivity (anaphylactic shock), difficulty breathing, dizziness and vomiting may occur. If it comes to a circulatory failure with impaired consciousness, cold sweating as well as pale and cold hands and feet, a doctor must be called for help immediately. Until the patient arrives, the patient's upper body is flat and their legs are high. To avoid hypothermia, the patient should be kept warm with a blanket. The usual appropriate emergency measures (e.g. antihistamines, corticosteroids, sympathomimetics and, if necessary, ventilation) must be initiated and treatment with metronidazole discontinued immediately.

Low blood platelets (thrombocytopenia). Lack of certain white blood cells (agranulocytosis). Agranulocytosis can set in within a few hours. The symptoms are fever, fatigue, and inflammation of the tonsils and the oral mucosa. In these cases, a blood count must be checked quickly. In such a case, contact your nearest doctor immediately.

Inflammation of the pancreas.

If severe, persistent diarrhea occurs during or in the first few weeks after treatment, pseudomembranous enterocolitis (severe bowel disease) should be considered (in most cases caused by Clostridium difficile). This bowel disease caused by antibiotic treatment can be life threatening and requires immediate medical attention. Depending on the indication, the doctor must consider discontinuing therapy with metronidazole and, if necessary, immediately initiate appropriate treatment (e.g. taking special antibiotics / chemotherapeutic agents whose effectiveness has been clinically proven). Medicines that inhibit bowel movement (peristalsis) must not be taken.


Nerve disorders (peripheral neuropathies) and seizures. The former manifest themselves as numbness, furiness, or tingling in the arms and legs. Even if these symptoms occur only in mild form, you must inform your doctor immediately!

Pathological changes in the brain, cerebellar syndrome (with e.g. speech and gait disorders, eye tremors and muscle twitching). Severe skin reactions (e.g. erythema multiforme; inflammatory skin disease with reddening). Inflammation of the liver sometimes with jaundice.

4.1.b) Other possible side effects

4.1.b.1.Very common

Nausea, abdominal pain e.g. stomach pressure, metallic taste.

4.1.b.2. Frequently

Bitter belching, coating on the tongue, inflammation in the mouth (glossitis, stomatitis), vomiting, loss of appetite, diarrhea. Dark color of the urine (due to a metabolic product, without disease value).


Headache, dizziness, drowsiness, insomnia, states of confusion, excitability, sad mood (depression), disturbances in the interaction of movements (ataxia). Skin reactions (e.g. itching, hives with blistering and wheals [urticarial rash]), drug fever. Decrease in white blood cells (leukopenia and granulocytopenia). With prolonged use, regular blood counts should be carried out.

Rapid onset of hypersensitivity reactions (anaphylactic reactions).In mild cases, inflammatory redness, wheals, allergic rhinitis and allergic conjunctivitis of the eye can occur.

Painful urination (dysuria), inflammation of the bladder (cystitis) and involuntary leakage of urine (urinary incontinence). Liver dysfunction. Infections with a skin fungus, Candida albicans, in the genital area. Feeling weak (muscular), visual disturbances.

The type and severity of side effects are the same in children and adults.

4.2 What countermeasures should be taken if side effects occur?

Let your doctor know if you experience any side effects. He will decide on possible measures.

If you experience a sudden or severe side effect, inform a doctor immediately, as certain drug side effects (e.g. excessive drop in blood pressure, hypersensitivity reactions) can under certain circumstances have serious consequences. In such cases, do not continue to take the medicine without doctor's advice.

Tell your doctor or pharmacist if you notice any side effects not listed here or in the package insert.

5. How should "Metronidazole" be stored?

Store "Metronidazole" at normal room temperature and keep the medicine in the original packaging, away from light and moisture.

Medicines should generally be kept out of the reach of children.

Do not use the medicine after the expiry date stated on the pack.

Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer need. This measure helps to protect the environment.

6. Source and processing status

Information from the SCHOLZ database based on the data approved by the Federal Office for Drugs and Medical Devices

Copyright by ePrax GmbH, Munich; February 2013 (3)