Zidoval Vaginal Gel

Zidoval is a vaginal gel containing metronidazole — the same active ingredient as the oral metronidazole tablets covered earlier — but at a low concentration (0.75%) and applied directly inside the vagina rather than swallowed. It's used to treat bacterial vaginosis and works through exactly the same mechanism as the tablets: damaging the DNA of anaerobic bacteria and allowing the protective lactobacilli to recover.

The most important difference is where the medicine ends up. Oral metronidazole circulates throughout the entire body and produces systemic side effects — the metallic taste, the nausea, the alcohol reaction. Zidoval, by contrast, places a small amount of metronidazole directly onto the vaginal lining, with only a fraction of the dose making it into the bloodstream. The result is a treatment that's almost as effective as the tablets for typical BV but with significantly fewer systemic side effects. The trade-offs are that it requires inserting a gel each night, can be a little messy, and isn't always the right choice in more severe or recurrent cases where the tablets' systemic reach can be useful.

The standard regimen is one applicator-full (5 g of gel, containing around 37.5 mg of metronidazole) inserted into the vagina at bedtime for five consecutive nights. Each applicator is single-use and prefilled. As with Dalacin, bedtime is the recommended time so the gel has the longest possible contact with the vaginal lining and the least chance of leaking out. A panty liner overnight is sensible.

This is one of the most common questions about Zidoval, and the answer needs a small amount of nuance. Because so little metronidazole is absorbed from a vaginal gel, the disulfiram-like reaction described under oral metronidazole is much less likely — and many clinicians take a relaxed view on alcohol with Zidoval. However, the manufacturer's product information still advises caution, and UK guidance generally recommends avoiding alcohol during treatment and for 48 hours after the last dose, just as with the tablets. Given how unpleasant the reaction is when it does occur, most patients find it easier to follow the same alcohol rules as for oral metronidazole and not take the chance, particularly during the few nights of treatment.

Local effects predominate: vulvovaginal irritation, itching, mild burning on application, increased discharge, and occasional cramping. Some women develop a yeast infection (thrush) during or shortly after treatment, just as with Dalacin, because reducing the anaerobic bacteria can give Candida species more room to grow. Systemic side effects — the metallic taste, nausea, headache — are much rarer than with oral metronidazole but aren't impossible, because a small amount of the drug is still absorbed.

This is a useful distinction. The oily base in Dalacin weakens latex; Zidoval is a water-based gel and does not have the same effect on latex condoms or diaphragms. Even so, having sex while a vaginal gel is in place isn't usually recommended because it can wash the medicine out and make it less effective, and it can be messy and uncomfortable for both partners. Most prescribers suggest avoiding penetrative sex during the five nights of treatment.

Most women notice an improvement in discharge and odour within two to three days, with full resolution of symptoms by the end of the five-night course. If symptoms haven't begun to improve by mid-course, or if they're worsening, it's worth checking in with a clinician.

Yes, in most cases. Because systemic absorption is low, Zidoval delivers a significantly smaller systemic dose than oral metronidazole — which makes it an attractive option in pregnancy. Untreated BV is associated with preterm birth and late miscarriage, so treatment is genuinely worthwhile, and current UK guidance supports the use of vaginal metronidazole in pregnancy when needed. Breastfeeding can usually continue normally, given the low maternal blood levels achieved with the gel.

Recurrence is unfortunately common with any BV treatment — around half of women have another episode within twelve months. The same general advice applies as for the tablets and Dalacin: avoid douching and scented intimate products, consider condom use with new partners, and discuss longer or maintenance regimens with your prescriber if the problem is persistent. Some women are placed on intermittent maintenance Zidoval — for example, twice-weekly use for several months — to suppress recurrences, although the evidence base for this is moderate rather than strong.

It's reasonable to seek a review if your symptoms haven't improved by the end of a course of treatment, if BV recurs within a few weeks of finishing treatment, if you develop new or unusual symptoms (such as pelvic pain, fever, abnormal bleeding, or sores), or if you've had three or more episodes in a year. Repeated self-treatment without review can mask other diagnoses, including sexually transmitted infections and, rarely, more serious gynaecological problems, so a periodic in-person assessment is worth doing rather than reordering treatment indefinitely.