Metronidazole (Intravenous)

Metronidazole is an antibiotic that is used to treat serious bacterial infections and to prevent the growth of bacteria before and after surgery in some cases.


Metronidazole is an antibacterial antibiotic injection that is used to fight bacterial infections in different parts of the body. In some patients it may also be given before and after surgery to prevent infections from occurring in the intestines.

The antibiotic treatment works by killing the bacteria and preventing the growth and spread of bacteria. As such the medication can have unwanted side effects because it will also kill healthy bacteria in the body.

This medication is not effective in the treatment of any viral infections and will not work as a treatment for colds or flu.

Metronidazole should only ever be given under the direct supervision of a doctor. It is provided as a solution or powder for solution and is injected directly into the veins of the patient.

Condition treated

  • Infection
  • Infection, prevention of

Type Of Medicine

  • Antibiotic

Side Effects

In addition to the required effects of Metronidazole, this medication may also cause some other unwanted side effects to occur. While not all side effects may occur, where they do you may need to seek medical attention for their treatment.

In the following cases, it is important that you seek immediate medical attention. These side effects can be serious and may indicate wider medical problems that are occurring:

Occurring more commonly:

  • Weakness in the arms, hands, legs, or feet
  • Vomiting
  • Unusual tiredness or weakness
  • Unsteadiness or awkwardness
  • Stiff neck or back
  • Seizures (convulsions)
  • Nausea
  • Mood or mental changes
  • Irritability
  • Headache
  • Hallucinations
  • Fever
  • Eye pain
  • Drowsiness
  • Dizziness
  • Decreased vision
  • Confusion
  • Burning, numbness, tingling, or painful sensations in the hands or feet
  • Blurred vision
  • Blindness
  • Back pain
  • Agitation

Frequency of incidence not known:

  • Unusual bleeding or bruising
  • Unsteadiness or trembling
  • Ulcers, sores, or white spots in the mouth
  • Trouble with speaking
  • Sores, ulcers, or white spots in the mouth or on the lips
  • Sore throat
  • Slurred speech
  • Shortness of breath
  • Shakiness and unsteady walk
  • Redness of the face, neck, arms, and occasionally, upper chest
  • Red, irritated eyes
  • Red skin lesions, often with a purple center
  • Problems with muscle control or coordination
  • Pale skin
  • Painful or difficult urination
  • Pain, tenderness, or swelling of the foot or leg
  • Lower back or side pain
  • Joint or muscle pain
  • Itching
  • Feeling of warmth
  • Fainting
  • Diarrhea
  • Cough
  • Chills
  • Chest pain
  • Changes in speech patterns
  • Changes in skin color
  • Blistering, peeling, or loosening of the skin
  • Black, tarry stools

Some other unwanted side effects can also occur that would not normally require that you seek medical attention. These side effects will usually abate with time and do not normally indicate the development of wider medical problems. You should inform your doctor if these side effects do become bothersome or are ongoing:

  • Unpleasant metallic taste
  • Stuffy nose
  • Skin rash
  • Redness of the skin
  • Hives or welts
  • Dry mouth
  • Abdominal or stomach discomfort

Other side effects can also occur from the use of this medication that may not have been listed herein. If you experience any other side effects not listed here then contact your doctor for advice. If you believe your health to be at immediate risk, however, then you should always contact the emergency services.


This medication will always be administered by a nurse or other trained healthcare professional in a hospital environment. The medication will be given through a needle placed into the veins.

When being used to treat an infection you will be given a few doses of the medication until your condition begins to improve. You will then be changed to a less potent oral medication that works in the same way.

If you have any concerns about the use of this treatment then you should contact your doctor.


Certain medications should never be used together. This is because they can interact in the body and cause serious complications. In extreme cases, these can be life-threatening. In other cases, certain treatments may prevent one another from working properly or may increase the side effects experienced. Sometimes medications may need to be used in conjunction with each other and dosage adjustments will need to be made to allow this.

To avoid medication interactions you must inform your doctor of all medications you are taking before you receive treatment. This includes all prescribed medications, medications purchased over the counter and any other substances you are taking. This is especially important in all of the following cases:

The use of Metronidazole with the following medications is not normally recommended. Your doctor may decide not to treat you with this medication if you are taking any of the following:

  • Ziprasidone
  • Thioridazine
  • Terfenadine
  • Sparfloxacin
  • Saquinavir
  • Pimozide
  • Mesoridazine
  • Dronedarone
  • Dronabinol
  • Disulfiram
  • Cisapride
  • Bepridil
  • Amprenavir
  • Amisulpride
  • Amifampridine

Using Metronidazole with any of the following treatments is not normally recommended, but in some cases it may be required. If both treatments are given together then adjustments may need to be made to one or both to prevent further complications from occurring:

  • Zuclopenthixol
  • Warfarin
  • Vorinostat
  • Voriconazole
  • Vinflunine
  • Vilanterol
  • Venlafaxine
  • Vemurafenib
  • Vardenafil
  • Vandetanib
  • Triptorelin
  • Trimipramine
  • Trazodone
  • Toremifene
  • Tolterodine
  • Tizanidine
  • Tetrabenazine
  • Telithromycin
  • Telavancin
  • Telaprevir
  • Tegafur
  • Tamoxifen
  • Tacrolimus
  • Sunitinib
  • Sulpiride
  • Sotalol
  • Sorafenib
  • Solifenacin
  • Sodium Phosphate, Monobasic
  • Sodium Phosphate, Dibasic
  • Sodium Phosphate
  • Sevoflurane
  • Sertindole
  • Ritonavir
  • Risperidone
  • Rilpivirine
  • Ranolazine
  • Quinine
  • Quinidine
  • Quetiapine
  • Protriptyline
  • Propafenone
  • Promethazine
  • Prochlorperazine
  • Procainamide
  • Probucol
  • Posaconazole
  • Pitolisant
  • Pipamperone
  • Pimavanserin
  • Perphenazine
  • Perflutren Lipid Microsphere
  • Pentamidine
  • Pazopanib
  • Pasireotide
  • Paroxetine
  • Panobinostat
  • Paliperidone
  • Ondansetron
  • Olanzapine
  • Ofloxacin
  • Octreotide
  • Norfloxacin
  • Nilotinib
  • Nelfinavir
  • Nafarelin
  • Mycophenolic Acid
  • Mycophenolate Mofetil
  • Moxifloxacin
  • Mizolastine
  • Mifepristone
  • Methadone
  • Mefloquine
  • Mebendazole
  • Lumefantrine
  • Levofloxacin
  • Leuprolide
  • Lapatinib
  • Ketoconazole
  • Ivabradine
  • Itraconazole
  • Imipramine
  • Iloperidone
  • Ibutilide
  • Hydroxyzine
  • Hydroxychloroquine
  • Hydroquinidine
  • Histrelin
  • Haloperidol
  • Halofantrine
  • Granisetron
  • Goserelin
  • Gonadorelin
  • Gemifloxacin
  • Gatifloxacin
  • Galantamine
  • Fosphenytoin
  • Foscarnet
  • Formoterol
  • Fluoxetine
  • Fluorouracil
  • Fluconazole
  • Flecainide
  • Fingolimod
  • Felbamate
  • Famotidine
  • Escitalopram
  • Erythromycin
  • Eribulin
  • Efavirenz
  • Ebastine
  • Droperidol
  • Doxifluridine
  • Doxepin
  • Donepezil
  • Domperidone
  • Dolasetron
  • Dofetilide
  • Disopyramide
  • Deslorelin
  • Desipramine
  • Delamanid
  • Degarelix
  • Dasatinib
  • Dabrafenib
  • Cyclobenzaprine
  • Crizotinib
  • Clozapine
  • Clomipramine
  • Clarithromycin
  • Citalopram
  • Ciprofloxacin
  • Cholera Vaccine, Live
  • Chlorpromazine
  • Chloroquine
  • Capecitabine
  • Busulfan
  • Buserelin
  • Bupropion
  • Bedaquiline
  • Azithromycin
  • Atazanavir
  • Astemizole
  • Asenapine
  • Arsenic Trioxide
  • Aripiprazole
  • Apomorphine
  • Anagrelide
  • Amitriptyline
  • Amiodarone
  • Alfuzosin

Using this medication in conjunction with the following can increase the risk of certain side effects and also increase their severity. If you are prescribed both then the doctor may adjust your dose or frequency of use of one or both treatments:

This list of medication interactions has been selected for severity only and may not be all-inclusive. Ensure that your doctor is aware of all other substances you are taking before you begin treatment with Metronidazole.

This medication can also interact with ethanol in the body, which is present in alcohol. You should not drink when you are using this medication. Discuss this with your doctor if you have any concerns about this.

Other medical problems from which you suffer can also affect your use of Metronidazole. This is because some medications can make other medical conditions worse and certain conditions may increase the side effects of medications. You should inform your doctor of all medical problems from which you suffer before beginning use of this treatment. This is especially important if you are suffering from the following conditions.

These conditions may be worsened by the use of Metronidazole:

The side effects and effects of this medication may be increased in patients with the following conditions:

Metronidazole use may also be affected by other medical conditions from which you suffer that are not listed herein. You must inform your doctor of your full medical history before beginning use.


Before beginning use of this or any other medication it is important to consider the risks of use in relation to the benefits of use. You should weigh the risks against the good that it will do with your doctor. You should also ensure that all of the following has been taken into account before you begin use of Metronidazole:

Allergies You must inform your doctor of all allergies from which you suffer before using this treatment. This includes any allergies to dyes, preservatives, foods, animals or other substances. It is especially important that you inform your doctor if you have ever reacted badly or unusually to any medications or antibiotics in the past. Certain allergies may prohibit the use of this medication.

Pediatric There have been no tests carried out for the use of this medication in children and the safety and efficiency of it have not been established. Alternative medications will be found for use in children.

Geriatric Appropriate studies have not uncovered any geriatric-specific limitations to the use of this treatment. Elderly patients are, however, more likely to be suffering from other medical problems of the liver, kidney or heart that may prohibit the use of this treatment. Proceed with caution in these cases.

Pregnancy There is a risk to the use of this medication when pregnant although it is low. You should discuss pregnancy with your doctor before use if you are pregnant. You may be treated with another medication or may still be given this medication where the benefit outweighs the risks.

Breastfeeding The risk of breastfeeding while using this medication is unknown. You should discuss the potential risks with your doctor before taking this medication. Weigh the benefits of continuing to do so against the potential risks and their impact.

Your doctor will need to regularly check up on you while you are being given this medication. You will be treated repeatedly until your doctor determines that your condition has improved enough to move you on to the oral dose of this medication. You will then need to be further checked during use of this until the infection has fully cleared and the doctor signs you off to stop the treatment. You may need to give blood and urine samples during this full period to check for any unwanted side effects that could be occurring.

Patients should not be given Metronidazole if they have also received disulfiram within 2 weeks of treatment. The use of these medications closer than this can cause serious medical complications.

You should not drink alcohol during your use of this medication. To do so may cause severe discomfort including the following:

  • Stomach pain
  • Nausea
  • Headache
  • Vomiting
  • Flushing
  • Redness of the face

Other preparations that also contain alcohol or ethanol may also cause these side effects. Drinks containing alcohol may also taste different when you are taking Metronidazole.

You should continue to abstain from alcohol for at least three days after finishing your treatment with Metronidazole.

If you experience any loss of coordination, loss of ability to speak, slurring of speech or shakiness then you should contact your doctor immediately. These symptoms can be a sign of a serious brain condition developing that is known as encephalopathy. This condition will need to be treated immediately to prevent permanent damage.

A condition called neuropathy may occur with this medication. You should contact your doctor if you experience any burning, numbness or painful sensations, particularly in the hands, legs, arms and feet.

Aseptic meningitis can occur from the use of this medication. Contact your doctor if you experience confusion, loss of appetite and a stiffening of the neck and back.


This medication will be stored in the hospital for injection.

Once treatment with the injected medication is complete the patient will be given an oral version of the medication to take regularly until the infection is gone. Please see storage instructions for this medication in the Metronidazole (oral route) information.


Metronidazole is an injected antibiotic treatment that is used to fight off serious bacterial infections in different parts of the body. It is given only under the supervision of a doctor and is injected directly into the veins. Patients may be treated with a number of doses of this medication until their condition improves. Following this, the patient will be changed onto an oral version of the medication that will be used until the patient is fully cured.

Patients should not consume any alcohol during treatment with this medication. To do so will put them at serious risk of medical complications occurring.