Metronidazole

What is Metronidazole?

Metronidazole is an antibiotic that works against a number of bacteria and parasites. It’s prescribed to treat a wide variety of conditions including skin infections and pelvic inflammatory disease. It can also be used to clear sexually transmitted infections (STIs) like trichomoniasis.

Trichomoniasis, sometimes referred to as ‘trich’, is a common infection caused by a parasite called Trichomonas vaginalis. Symptoms of this condition usually appear within a month of transmission, although half of the women and up to half of the men who develop trich won’t get any symptoms whatsoever.^[1]

The parasite that causes trich is usually spread through unprotected sex. When symptoms do develop, they are often similar to other STIs. Women who develop an infection usually experience a soreness around their genitals, including redness, itching and burning. It can be uncomfortable to urinate, and often the infection produces a clear, yellow, or green discharge with an unusual smell. Men with trich experience similar symptoms, including irritation inside their genitals, a burning sensation after urinating, and a thin, white discharge from their penis.

How does Metronidazole work?

Metronidazole works by preventing the growth of bacteria and parasites that cause infections. It’s one the most commonly prescribed antibiotic medications, and is used to treat a range of bacterial infections.^[2]

But because trich is caused by a parasite, not a bacterial infection, Metronidazole works a little differently when treating it. The tablets have a ‘cytotoxic’ effect on the trichomoniasis parasite. Cytotoxicity is the ability a substance has to cause damage to certain cells. This means Metronidazole works by breaking down and destroying the parasite (Trichomonas vaginalis) that’s causing your trich infection.

Metronidazole is sometimes prescribed in the form of a topical cream, lotion, or gel to treat skin conditions like rosacea. It’s also used intravaginally (inside the vagina) to treat bacterial vaginosis.

What doses of Metronidazole are there?

When treating trich, Metronidazole is usually given as 400mg or tablets (but right now, we only offer the 400 mg tablets).

The usual dose is one 400mg tablet twice a day, for 7 days.

To avoid missing a dose or making any mistakes while using Metronidazole, you could try setting an alarm as a reminder for when you’re due to take your tablets. To prevent the infection returning, make sure you take each dose of your antibiotics until the course is complete.

How to take Metronidazole

Metronidazole tablets should be swallowed whole with a glass of water. Taking them during (or just after) a meal will help you avoid indigestion or stomach irritation. You should never crush or chew the tablets.

Stopping antibiotics during a course of treatment can mean that some of the pathogen causing your infection is still present in your system. That’s why it’s essential to stick to your dose routine as it’s been advised, and finish the full course of Metronidazole.

Does Metronidazole work right away?

Antibiotics are the usual treatment for trichomoniasis.^[1] They work quickly, and once you’ve finished a course of tablets, you shouldn’t need any further medication as that’s usually enough to clear the infection.

You might start to feel better after a few days of treatment with Metronidazole, but it’s important to take the full seven day course of tablets to allow the antibiotics to work properly. If you’ve seen no improvement after seven days, talk to a clinician about alternative STI treatments or additional testing.

What should I do if I make a mistake when using Metronidazole?

Taking Metronidazole exactly how it’s been prescribed by a clinician will mean you’re unlikely to make any mistakes while you’re using the tablets.

If you’ve taken more tablets than you need, get medical attention right away. A doctor will find it easier to treat you if you can provide as much information as possible on arrival, so it’s best to bring the box that your Metronidazole tablets arrive in.

You should never double your dose of antibiotics if you miss a tablet. Instead, wait until your next dose is due and continue your treatment plan from there.

You should avoid drinking alcohol while you’re using Metronidazole (and for 48 hours after), as it can cause vomiting and abdominal pain. If you’re pregnant or breastfeeding, let a clinician know before starting a course of tablets. Metronidazole can sometimes cause sleepiness and bouts of dizziness – if you’re feeling like this at any point while you’re using it, you should avoid driving.