Metronidazole

Metronidazole is the name of the ingredient used to treat several types of bacterial infection.

Metronidazole is sold under different brand names. Flagyl (also Flagyl ER, Flagyl 375 etc.), which is perhaps the most well-known name, is the brand dedicated to tablets and suppositories. Rosiced and Rozex are names for metronidazole as a cream, while the gel can be found as Acea, Anabact, Metrogel, Zyomet and Metrosa. The vaginal gel is sold as Zidoval. Generic versions will typically have the name of the active ingredient ‘Metronidazole’ on the packaging. Generic versions are just as effective as branded alternatives.

Is Metronidazole a penicillin?

No. Metronidazole is an antibiotic used to treat bacterial infections. There are no known interactions between Metronidazole and penicillin, and these may be prescribed together by healthcare professionals to combat severe oral infections where an initial course of treatment with antibiotics has not been effective.

Metronidazole is a treatment for anaerobic bacterial infections, parasitic infections (protozoal), and microaerophilic bacterial infections.

Some of the most common infections Metronidazole can treat are bacterial vaginosis (Gardnerella vaginalis infection), pelvic inflammatory disease (PID), the sexually transmitted infection (STI) trichomoniasis, and some cases of rosacea.

Other infections Metronidazole can successfully treat include those present in the mouth, intestines (giardiasis), liver (liver diseases such as liver abscess), bones and genital tract. This medication is also used to prevent infections occurring after surgery.

Metronidazole is administered differently depending on the type of infection.

Metronidazole targets bacteria in the body directly, working with your body's immune system to clear the infection.

Entering bacterials cells and influencing their ability to create DNA, Metronidazole slows the infection's progress and growth. Because the bacteria can't spread, the symptoms that are associated with these infections are reduced and weakened, offering you relief from any discomfort you might be feeling. By stopping the infection's progress, your immune system can target the affected area.

Some bacterial infections can be treated with one single dose. However, this does not apply to all conditions. Below are some examples of how quickly it can clear up some of the different infections (in adults 18 years or older):

• Bacterial vaginosis can be treated as a strong single-dose with tablets in 1 day, 5-7 days using lower-dose tablets, or 5 days using a vaginal gel
• Urogenital trichomoniasis can be treated by mouth in as little as 1 day taking 1 high-strength tablet, or in 5 days or 5-7 days with lower dosages
• Pelvic inflammatory disease is treated in 14 days with tablets taken orally
• Rosacea needs consistent treatment for anything between up to 6 weeks or 4 months, depending on the brand of the medicine

Taking a stronger dose for faster results is not always advised. There are studies to suggest that a multi-dose of metronidazole is more effective compared to a single-dose treatment.

Can I stop taking metronidazole early?

It can sometimes be uncomfortable having to take treatment over a longer period of time, and it is understandable that as soon as the symptoms are starting to clear up you might want to ditch the treatment. However, you should never do this.

If symptoms are starting to, or have already cleared up, this does not mean the infection is gone. Finishing a course of treatment early, before the infection has fully cleared up, can lead to a worsened infection and antibiotic resistance. This means that future infections may not respond as well to antibiotic treatments, and could in turn become incurable.

If you have completed your full course, and been given the ‘all clear’ by your doctor, and for some reason have leftover medicines, you should know how to discard these safely. You should never save these for a ‘just in case’ future use, as medicines should always be used by their expiry or use by date.

Medicines that are out of date or medicines not stored correctly can lead to worsened infections and antibiotic resistance. Always read the patient information leaflet (PIL) on how to use and store your medicines.

As this treatment is used for a wide range of conditions, you should always refer to the advice of your doctor, and the enclosed drug information, on how to take the treatment for the condition you are treating.

The method of which you shall administer Metronidazole, as well as the dosing, will depend on your tolerance to the treatment as well as what you are using it for.

• Tablets are administered orally and should be swallowed whole with a glass of water after food. You should refer to your doctor’s advice on how many times daily, and for how many days, you should take the tablets for
• Cream and gel is applied directly onto the infected area (as a topical treatment) and gently rubbed into the skin. They are usually applied 1-2 times daily, and the treatment course can last several weeks or months depending on the severity (and the type) of condition
• Vaginal gel comes with a gel applicator that is inserted into the vagina to deliver the dose. Typically the treatment course is 1 dose at night for 5 consecutive nights

You should always follow the advice of your doctor or pharmacist on how to take this treatment and for how long. You should never stop treatment early, even if you are feeling better.

You should inform any sexual partners you may have if you are taking this to treat a sexually transmitted infection, as it is important they also get tested and treated. You should ensure a test comes back negative after the treatment course has been completed to ensure the infection has fully cleared up.

How to deal with a missed dose:

• if it is nearly time for your next dose, wait till your next dose instead
• if it is not time for your next dose yet, take it as soon as you remember
• never take 2 doses at the same times, unless specified by your doctor
• for once daily treatments, never administer the dosage twice in one day to make up for a missed dose
• if you frequently forget to take your medicine, you could benefit from setting a recurring reminder
• if you accidentally take 1 extra dose, it is usually not harmful. Speak to a healthcare professional if you take more than 1 extra dose

Can I take metronidazole while on my period?

It is not recommended to use the vaginal Metronidazole gel, cream or suppositories if you are on your period or expecting your period to begin during the course of treatment.

It is however important to not stop treatment once you have started, so if you unexpectedly start your period while on this treatment, do not stop. You should also use pads instead of tampons, as tampons can absorb the medicine.

Metronidazole tablets, gels or creams for topical use on the skin should not be affected by periods.

No. While taking Metronidazole or other antibiotic treatments it is not advised to drink alcohol. It is advised to not consume alcohol before, during and for at least 2 days after taking this treatment. When combined, unpleasant side effects can occur, such as headaches, abdominal cramps (stomach pain), nausea, flushing and vomiting.

This is less likely to happen if using vaginal Metronidazole gel, but it is still not recommended to drink alcohol during the treatment course.

Most adults and children can use Metronidazole. Metronidazole and other antibiotics should only be used if prescribed by a doctor or healthcare professional to treat or prevent certain types of infections. Although it is safe to take for most, some should not take it. This could be due to allergies, pregnancy, or taking certain other medicines, etc.

If any of the below applies to you, you should inform your doctor, as Metronidazole may not be the right treatment for you:

• you are allergic to metronidazole, any of its ingredients, or have had an allergic reaction to medicines in the past
• you are pregnant or breastfeeding
• you consume alcohol or medicines containing propylene glycol and will not be able to stop while taking this treatment
• you have problems with your liver or having dialysis
• you suspect you may have thrush (applies to vaginal gel only)

Can I take Metronidazole while pregnant or breastfeeding?

Generally speaking, it should be safe to take Metronidazole while pregnant and breastfeeding, and there is lots of research available to confirm this. There has never been any evidence found of Metronidazole causing premature birth, low birth weight, or congenital anomalies, in the first trimester or in later trimesters.

A higher single-dose treatment produces higher levels in breast milk compared to the lower multi-dose treatments. This means that the high doses may give breast milk a bitter taste. It may therefore be recommended to use a low-dose oral treatment, up to 500mg 3 times daily, as this is compatible with breastfeeding.

It is still important that you inform your doctor if you are either trying to get pregnant, currently are pregnant or if you are breastfeeding, as they will be able to recommend you the best treatment for you and your health condition.

All medicines can interact with others making them either more or less effective. Some medicines can also increase the risk of adverse effects. Where drug interactions are known, your doctor should review your treatments and adjust dosage or recommend an alternative that is safer.

Below are some medicines that have a severe interaction with Metronidazole.

• Warfarin
• Lithium
• Fluorouracil
• Disulfiram
• Capecitabine
• Busulfan
• ​​Acenocoumarol

Does it affect painkillers such as paracetamol and ibuprofen?

It does not. If you need painkillers such as ibuprofen or paracetamol, you are okay to take these. There are no known interactions between painkillers such as those and metronidazole.

Does it affect contraception (birth control)?

Warnings about antibiotics when using contraception is common. There is, however, no known interaction between contraception and antibiotics, such as metronidazole. If experiencing some of the common side effects such as vomiting and diarrhoea, your contraception may become less effective. You should refer to the patient information leaflet on what to do in these instances.

This will depend on what you would need Metronidazole for.

Bacterial vaginosis (BV), for example, can be treated using the medicine Fluomizin should Metronidazole not be recommended. BV can also be treated with Metronidazole in different dosages and application types, including a single-dose, multi-dose, or a vaginal gel. Single-dose and multi-dose are two options for a wide range of the infections Metronidazole is used to treat.

For rosacea, there are a wide range of treatments available in addition to Metronidazole, including topical treatments as well as oral medicine. Other treatments include Finacea, some acne treatments like isotretinoin (Roaccutane), and other antibiotics (in tablet form) such as tetracycline and doxycycline. Efracea, a low-dose doxycycline is often prescribed to treat rosacea, as higher dosages are more linked to adverse effects and antibiotic resistance.

Your doctor should be able to prescribe you the right treatment for your condition and advise you if you have concerns about using Metronidazole.

Typically, topical metronidazole creams and gels rarely cause side effects. Any adverse effects are more common with vaginal gel, suppositories and tablets.

Some common side effects of these are:

Somerarer side effects such as dark urine, vision disorders, drowsiness and headaches can also occur. It is not known how frequent other adverse effects such as constipation and other gastrointestinal disorders occur.

More serious side effects can occur, as well as allergic reactions, as with any treatment. For the full list of side effects, and information on allergic reactions, please refer to the PIL.

Consuming alcohol while using this treatment can cause other side effects. Do not consume alcohol while using Metronidazole. This includes consuming foods or taking any medicines containing alcohol (such as propylene glycol). The half-life of Metronidazole is about 8 hours, and it takes 5.5 times this to completely get rid of it out of your system. This means that it will take approximately 44 hours before it is out of your system after you have taken the last dose. You should therefore wait 2 days (44 hours) minimum before you consume alcohol after finishing your full treatment course. This is to prevent more serious and uncomfortable side effects from occurring.

What should I do if I experience side effects?

The side effects listed above are typically nothing to worry about, but should they not go away or they bother you, you should speak to your doctor. Do not stop taking the medicine before you have spoken to your doctor and they advise you to do this.

If you experience any serious side effects, please seek medical assistance. If you experience any side effects not listed here or in the PIL, you can report these on MHRA’s website YellowCard.

You can buy Metronidazole for certain conditions from online healthcare providers such as euroClinix.

All you have to do is select your treatment course and complete an online consultation. This will be reviewed by one of our doctors, and if considered a safe treatment for you, a prescription is generated and the medicine is shipped to you with next-day delivery.

It is important that you answer all the questions truthfully and provide as much information as you can about any other conditions you might have, as well as any medicines you are currently taking. This includes over-the-counter medicines, herbal medicines, supplements and prescription medicines.

The type of Metronidazole you will get, will depend on the treatment you need and which brands are available (in stock). The treatment you receive might differ from the product image on this page.

Can I get Metronidazole pills over the counter?

No. This is a prescription-only medicine, and can therefore only be issued if you have a valid prescription. A prescription can be issued from an online healthcare provider such as euroClinix, so that you do not have to visit your GP face to face for treatment.