Metronidazole (Topical)

As a topical antibiotic cream, Metronidazole is useful in treating bacterial infections of the skin and vaginosis.


Metronidazole, which is often branded and marketed as Flagyl and Metrocream among others, is an antibiotic and antiprotozoal medicine. As a topical cream, it can be used on its own or in conjunction with other antibiotic treatments to clear up skin infections, bacterial vaginosis and more. It is not suitable for treating yeast infections.

This medication was first used commercially in France in 1960. It is currently regarded as an essential medicine by the World Health Organization. This is because it is useful in treating a variety of different infections and has relatively low production and wholesale costs. For these reasons, it is one of the most widely prescribed antibiotic medicines in the world.

Metronidazole works by inhibiting the synthesis of nucleic acid by disrupting microbial cell DNA. It is useful in treating skin conditions because this inhibition of nucleic acid synthesis only happens in anerobic cells, without having the same effect upon human cells. This makes it effective in targeting sources of infection.

Type Of Medicine

  • Antibiotic

Conditions Treated

Side Effects

Like most medications, Metronidazole can potentially cause unwanted side effects in addition to its desired effects. The most common side effects reported by patients undergoing treatment with this medicine include the following:

  • Back pain
  • Agitation
  • Blurred vision
  • Blindness
  • Numbness, tingling, painful burning sensations in the feet or hands
  • Changes in speech
  • Confusion
  • Decreased vision
  • Convulsions
  • Depression
  • Drowsiness
  • Dizziness
  • Eye pain
  • Hallucinations
  • Fever
  • Irritability
  • Headache
  • Loss of co-ordination
  • Nausea
  • Shakiness
  • Unsteadiness when walking
  • Slurred speech
  • Stiff back or neck
  • Difficulty speaking
  • Trembling
  • Vomiting
  • Weakness in the legs, arms, hands or feet

Most patients will only experience minimal side effects while taking Metronidazole, if they experience any at all. Metronidazole is intended to alleviate symptoms of serious infection, and as such, it is usually prescribed because the benefits of combating infection far outweigh the risk of experiencing the mild discomfort of side effects.

As the patient continues to take Metronidazole as prescribed, most of the previously mentioned side effects should lessen. If they persist over a prolonged period or get worse, the patient should consult their doctor as soon as possible. In most cases, a doctor or pharmacist will be able to recommend over the counter remedies to alleviate symptoms of side effects.

Other side effects which are experienced less frequently, albeit often enough to warrant mentioning, include the following:

  • Chills
  • Body aches or pains
  • Tarry, black stools
  • Clumsiness
  • Congestion in the ear
  • Pelvic pressure
  • Painful or frequent urination
  • Voice loss
  • Nasal congestion
  • Red spots on the skin
  • Itching, redness, hives or skin rash
  • Stomach pain
  • Sneezing
  • Unusual bruising or bleeding
  • Vaginal irritation or discharge
  • Bloating
  • Chest pain
  • Constipation
  • Dark-colored urine
  • Indigestion
  • Fast heartbeat
  • Appetite loss
  • Swollen glands
  • Yellowing of the skin/eyes
  • Feeling of warmth
  • Red, irritated eyes
  • Loss of bladder control

One rare side effect of Metronidazole concerns the way it can affect the psychology of the patient. He or she may experience frequent mood swings, confusion, depression and/or hallucinations. Care should therefore be taken when prescribing this medication to patients with a history of mental health conditions such as bipolar disorder and schizophrenia.

Because Metronidazole can cause dizziness and affect the co-ordination of the patient, it is advisable that patients refrain from driving or operating heavy machinery in the workplace, until it has been observed that these side effects do not cause an issue in the individual. This is to prevent the patient or other road users from becoming injured.

Not all side effects may have been reported. Patients who feel they may have experienced a side effect which is not listed on the literature provided with this medication should contact their doctor and report any findings to the FDA.


Like all medications, it is vital that the patient takes Metronidazole only as prescribed by a doctor. This means patients must avoid taking any more of the drug than advised, both in terms of frequency of use and dose size. In addition to this, the patient should be prepared to discontinue Metronidazole use if advised to do so by a doctor even if they still have a supply of the medicine remaining.

Doses may vary dependent on the individual needs of the patient. It is therefore important for the patient to take heed of what the doctor says at the time of prescribing this topical cream. Otherwise, the instructions printed on the side of the medication packaging can be adhered to, as these should be similar or the same as the doctor's instructions.

When determining dose size, a doctor will take a number of factors into account, including the number of doses per day, strength of the medicine, time between doses and the length of time the patient will be undergoing treatment with the medicine. The manufacturers provide general dose instructions, but it should be reiterated that these are merely recommendations which can be altered by the patient's doctor.

Metronidazole is available as a topical gel in 0.75% and 1% concentration topical creams and gels, and a 1.3% concentration gel specifically for vaginal use.

Usual adult dose for Acne Rosacea: apply a liberal amount and rub into a thin layer to the affected area, once every day. A gentle skin cleanser should be used prior to application, and cosmetics can be applied after application.

Usual adult dose for bacterial vaginosis: One applicator full of 1.3% Metronidazole vaginal gel should be applied intravaginally, at bedtime, every day until infection has cleared.

Patients are warned against taking double doses. In the event of a missed dose, the patient should simply apply the cream as soon as they realize. If it is closer to the time for the next dose, the patient should omit the missed dose and take the next scheduled dose as standard.

If the patient experiences signs or symptoms of overdose after using Metronidazole or any other drug, they may require immediate medical attention and should contact their local poison control center on 1800-222-1222 or emergency services on 911.


All drugs have the potential to interact with other medicines within the body. These interactions can change the effects of the medications involved, causing them to become ineffective or causing dangerous reactions to occur in the patient. Because of these risks, it is important for patients to keep a detailed list of all medicines they are currently undergoing treatment with. This applies to vitamins, complimentary medicines, herbal supplements and over the counter remedies as well as prescribed drugs.

Below is a partial list of drugs known to majorly interact with Metronidazole. Patients who are taking any of these medicines should inform their doctor prior to applying Metronidazole topical cream:

  • Amprenavir
  • Warfarin
  • Tipranavir
  • Ritonavir
  • Ethanol
  • Disulfiram
  • Black cohosh
  • Lithium


Skin should be washed and gently dried before Metronidazole topical cream is applied. It should be rubbed in completely.

Do not use Metronidazole to treat any skin conditions which have not been checked out by a doctor.

This medication should be used for the full period of prescription. Some patients notice that their symptoms improve before the course of treatment has been completed and stop using Metronidazole. This can increase the risk of developing further antibiotic-resistant infection.

If symptoms do not improve or get worse while using this medication, the patient is advised to consult their doctor.

Metronidazole topical cream is not expected to cause any issues to unborn babies. However, patients who are pregnant or intending on becoming pregnant soon should inform their doctor before using this or any other medicine.

It is not currently known whether Metronidazole topical cream is passed into breast milk, or whether it could have any adverse effects on a nursing baby. Patients who are breastfeeding are advised to discuss the risks of using antibiotic medications while doing so with their doctor or healthcare provider.


Metronidazole topical should be stored at room temperature, away from sources of heat or moisture. It is therefore unsuitable for storage in a bathroom cupboard and should instead be kept out of the reach of children in a locked medicine cabinet if possible.


Metronidazole is a greatly beneficial medication, but it can also pose a risk to patients who fail to communicate effectively with their physicians. As an antibiotic in topical cream form, it is designed to fight skin infections, some forms of acne and bacterial vaginosis. However, it can also cause confusion and dizziness which can affect the day-to-day functioning of the patient if the correct precautions are not taken. It can also interact with other medications. It is therefore in the best interests of the patient to be upfront with their doctor regarding their medical history.

When used correctly, Metronidazole is useful in beating superficial skin infections which can be unsightly or cause pain if left untreated. To achieve this, patient and doctor must work together to ensure that this medication is suitable for use, and to work out the most appropriate dosage and frequency of treatment.