Zidoval (Metronidazole)

What Is Zidoval Gel for Bacterial Vaginosis?

Bacterial vaginosis (BV) is one of the most common vaginal conditions affecting women of reproductive age in the UK. It occurs when the natural balance of bacteria in the vagina is disrupted, allowing certain anaerobic bacteria to overgrow. Symptoms typically include a thin, greyish-white discharge and a distinctive fishy odour — particularly noticeable after sex. If any of this sounds familiar, you are not alone, and there is an effective treatment available. Zidoval gel bacterial vaginosis treatment is a clinically established option that works directly at the site of infection, making it a practical choice for many women.

Zidoval is a 0.75% metronidazole vaginal gel manufactured by Numark. It is applied intravaginally once daily at bedtime for five consecutive nights. Because it is applied locally rather than taken by mouth, it tends to cause fewer systemic side effects than oral metronidazole, which some women find more manageable. If you are looking for broader support with women's health treatments, Cured Pharmacy stocks a range of relevant products to help.

How Does Zidoval Work Against Bacterial Vaginosis?

Metronidazole belongs to the nitroimidazole class of antibiotics. It works by entering bacterial cells and interfering with their DNA, preventing the bacteria from replicating and ultimately killing them. The key steps in its mechanism are:

• Metronidazole is absorbed into susceptible anaerobic bacterial cells.
• Inside the cell, it is reduced to a toxic intermediate compound.
• This compound binds to and disrupts the bacterial DNA strand.
• DNA synthesis is halted, the bacteria cannot reproduce, and they die off.
• The vaginal flora gradually restores its natural balance of lactobacilli.

Because the gel is applied directly into the vagina, it achieves a high local concentration of metronidazole at the site of infection. This targeted approach means the drug acts where it is needed most, without the same level of systemic absorption you would get from a tablet.

Who Is Zidoval Suitable For?

Zidoval is intended for adult women who have been diagnosed with bacterial vaginosis. It is not a treatment for thrush (candidal infection) or sexually transmitted infections, so it is important to have the correct diagnosis before starting treatment. Your GP or pharmacist can help confirm whether BV is the likely cause of your symptoms.

• Adult women with confirmed or suspected bacterial vaginosis.
• Women who prefer a localised vaginal treatment over oral tablets.
• Those who have previously responded well to metronidazole-based therapy.
• Women who experience recurrent BV and have discussed ongoing management with their GP.

Zidoval is not recommended during the first trimester of pregnancy. If you are pregnant, breastfeeding, or trying to conceive, speak to your GP before using this product. It should also be used with caution in women with a history of blood disorders or liver disease.

How Does Zidoval Compare to Oral Metronidazole for BV?

How Should You Store Zidoval and Is It Clinically Suitable for You?

Store Zidoval below 25°C and do not freeze it. Keep it in its original packaging, out of the sight and reach of children. Do not use the gel after the expiry date printed on the tube. Once opened, use the product within the treatment course as directed — do not save leftover gel for future use without speaking to a pharmacist first.

Clinically, Zidoval gel bacterial vaginosis treatment is well-tolerated by most women when used as directed. However, if you are also experiencing symptoms that could suggest a thrush or yeast infection alongside BV, it is worth getting a proper diagnosis, as the treatments differ significantly. Using the wrong treatment can delay recovery and potentially worsen symptoms.

This product is a medicine. Speak to your doctor or pharmacist before using if you have an underlying medical condition or are taking other medicines.

What Is Zidoval and What Is It Used For?

Zidoval is a vaginal gel containing metronidazole 0.75% as its active ingredient. It is used to treat bacterial vaginosis (BV) — a condition caused by an overgrowth of anaerobic bacteria in the vagina, which disrupts the normal acidic environment maintained by lactobacilli. BV is not a sexually transmitted infection, though sexual activity can sometimes trigger it. Common symptoms include an unusual greyish discharge and a fishy smell. Zidoval gel delivers metronidazole directly to the vaginal mucosa, targeting the bacteria responsible for the imbalance.

What Do You Need to Know Before Using Zidoval?

Before using Zidoval, it is important to be aware of the following contraindications and warnings:

• Do not use Zidoval if you are allergic to metronidazole, other nitroimidazoles, or any other ingredient in the gel.
• Do not use during the first trimester of pregnancy without medical advice.
• Avoid use if you are breastfeeding unless your doctor has specifically advised it.
• Do not use in children or adolescents under 18 years of age.
• Use with caution if you have a history of liver disease or blood disorders.
• Zidoval may weaken latex condoms and diaphragms — use alternative contraception during treatment.

The following medicines may interact with metronidazole, even when used vaginally:

• Warfarin — metronidazole can increase the anticoagulant effect, raising bleeding risk.
• Lithium — plasma lithium levels may increase; monitoring is advised.
• Alcohol — causes a disulfiram-like reaction (flushing, nausea, vomiting, palpitations). Avoid completely during treatment and for 48 hours after.
• Phenytoin — metronidazole may increase phenytoin levels.
• Ciclosporin — risk of elevated ciclosporin levels.

How Should You Use Zidoval Correctly?

Always use Zidoval exactly as directed. The standard course is one applicatorful inserted into the vagina each night at bedtime for five consecutive nights. Using it at bedtime reduces leakage and maximises contact time with the vaginal mucosa. Follow these steps carefully:

1. Wash your hands thoroughly before and after use.
2. Remove the cap from the tube and attach the applicator securely.
3. Squeeze the tube gently to fill the applicator to the marked line (approximately 5g of gel).
4. Lie on your back with your knees bent, or stand with one foot raised on a step.
5. Gently insert the applicator as far as is comfortable into the vagina.
6. Press the plunger slowly to release the gel, then withdraw the applicator.
7. Wash the applicator with warm soapy water after each use.

Zidoval is not indicated for use in children or adolescents. If symptoms do not improve after completing the five-night course, consult your GP. For women managing recurrent BV, it is worth exploring broader women's health support options alongside treatment.

What Are the Possible Side Effects of Zidoval?

Like all medicines, Zidoval can cause side effects, although not everyone experiences them. Because the gel is applied locally, systemic side effects are less frequent than with oral metronidazole — but they can still occur due to some absorption through the vaginal mucosa.

Common side effects (may affect up to 1 in 10 users):

• Vaginal irritation, burning, or itching
• Increased vaginal discharge
• Metallic or unpleasant taste in the mouth
• Nausea
• Headache

Less common side effects (may affect up to 1 in 100 users):

• Abdominal discomfort or cramping
• Dizziness
• Darkening of the urine (harmless but can be alarming)
• Overgrowth of Candida (thrush) — if this occurs, a separate antifungal treatment may be needed
• Skin rash or urticaria (rare)

Stop using Zidoval and seek medical advice immediately if you develop signs of a severe allergic reaction, such as swelling of the face, lips, or throat, difficulty breathing, or a widespread skin rash. If you notice signs of a vaginal yeast infection developing during treatment, you can browse thrush treatments available at Cured Pharmacy.

How Should You Store Zidoval Safely?

• Store below 25°C in a cool, dry place.
• Do not freeze the gel — freezing can alter its consistency and effectiveness.
• Keep in the original packaging to protect from light.
• Keep out of the sight and reach of children.
• Do not use after the expiry date printed on the tube and carton.
• Do not dispose of medicines via wastewater or household waste — return unused product to your pharmacy for safe disposal.