BV Treatment Options Compared: Metronidazole, Zidoval and Dalacin
Course length, effectiveness, side effects and the practical factors that decide which one suits you.
Part of the Bacterial Vaginosis condition guide.
Key fact: All three first-line BV treatments have broadly similar cure rates. The decision is almost always about alcohol, condoms, tolerability and course length — not about one being stronger than the others.
Get BV Treatment Online
Access Doctor provides BV treatment following a GPhC-regulated online consultation with our pharmacist independent prescribers.
Start a BV consultation →The three options side by side
Three treatments are used first line for bacterial vaginosis in the UK. All are prescription-only. Two are metronidazole in different forms, and one is a different antibiotic entirely.
| Metronidazole tablets | Zidoval gel | Dalacin 2% cream | |
|---|---|---|---|
| Active ingredient | Metronidazole 400mg | Metronidazole 0.75% | Clindamycin 2% |
| Route | Oral tablet | Vaginal gel | Vaginal cream |
| Course | Twice daily, 5–7 days | One applicator nightly, 5 nights | One applicator nightly, 7 nights |
| Alcohol restriction | Yes — during and 48h after | Yes — during and 48h after | No |
| Affects latex condoms | No | No | Yes — for up to 5 days after |
| Common side effects | Nausea, metallic taste, appetite loss | Local irritation, discharge, some thrush | Local irritation, thrush |
| Systemic absorption | Full | Minimal | Minimal |
| Use in pregnancy | Under clinical supervision | Under clinical supervision | Under clinical supervision |
Which one suits your situation
Rather than asking which treatment is best in the abstract, it is more useful to start from your own circumstances. This table maps the most common deciding factors onto the option that usually fits.
| If this applies to you… | Usually the better fit | Why |
|---|---|---|
| You do not want to avoid alcohol | Dalacin 2% cream | Clindamycin has no alcohol interaction; both metronidazole forms do |
| You rely on latex condoms or a diaphragm | Metronidazole tablets or Zidoval gel | Dalacin weakens latex for up to five days after the last dose |
| Oral antibiotics make you nauseated | Zidoval gel or Dalacin cream | Minimal systemic absorption means far less nausea and metallic taste |
| You want the shortest course | Zidoval gel | Five nights, versus seven for Dalacin and five to seven days for tablets |
| You would rather not use an applicator | Metronidazole tablets | Oral dosing avoids vaginal administration entirely |
| You get thrush after every antibiotic course | Zidoval gel | Lower systemic exposure; though local thrush can still occur |
| You are taking warfarin or lithium | Dalacin, or tablets with monitoring | Oral metronidazole interacts with both; discuss with your prescriber |
| You have had several oral courses already | Zidoval gel | Also the preparation used twice weekly for suppression in recurrent BV |
Diagnosis first. This comparison assumes BV has been confirmed or is clinically likely. If you are not sure whether your symptoms are BV or thrush, start with BV vs thrush — none of the treatments below will help if the problem is a yeast overgrowth.
Metronidazole tablets
Oral metronidazole 400mg twice daily for five to seven days is the NICE CKS first-line option and the treatment most women are given. It is well established, inexpensive and does not require vaginal administration.
- Taken with or after food, which reduces nausea considerably.
- No alcohol during the course or for 48 hours after the last dose.
- Nausea, a persistent metallic taste and reduced appetite are the usual complaints.
- Interacts with warfarin and lithium — declare all your medicines at consultation.
- The main practical drawback is the alcohol restriction over a full week.
Full detail on dosing, timing and missed doses is in how to take metronidazole, and the complete side effect picture is in metronidazole side effects and warnings. If you want background on the antibiotic itself, see what metronidazole is and what it treats.
Zidoval vaginal gel
Zidoval delivers the same antibiotic directly to the site of the problem. One applicator is inserted at night for five consecutive nights — the shortest standard course of the three.
Because very little metronidazole is absorbed into the bloodstream, the systemic side effects that make the tablets unpopular are largely avoided. The alcohol precaution still applies, since a small amount is absorbed.
Five nights only
The shortest first-line course, which some women find easier to complete than a seven-day oral regimen.
Minimal systemic effects
Much less nausea and metallic taste than tablets, because little of the drug reaches the bloodstream.
Also used for suppression
Twice weekly for three to six months is the established approach for genuinely recurrent BV.
Alcohol rule still applies
Avoid alcohol during the course and for 48 hours after the final application.
Application technique and the full cautions are covered in Zidoval vaginal gel for BV: how to use it.
Dalacin 2% cream
Dalacin is clindamycin rather than metronidazole, which makes it the option of choice when metronidazole is unsuitable — whether because of intolerance, an interaction, or simply because avoiding alcohol for a week is impractical. One applicator is inserted at night for seven consecutive nights.
Latex warning. Dalacin cream weakens latex condoms and diaphragms. Do not rely on them for contraception or protection against sexually transmitted infections during the course or for five days after the last application. Use an alternative method for that period.
Clindamycin can also cause diarrhoea, and persistent or severe diarrhoea during or after a course should be reported rather than treated at home. Detailed guidance is in Dalacin 2% cream for BV: how it works and how to use it.
How effectiveness actually compares
The honest answer is that the differences are small. Cure rates for a first episode are typically quoted in the region of 70 to 80% for all three, and head-to-head trials have not established a decisive winner. What differs meaningfully is tolerability and convenience — which is why the decision table above is more useful than a ranking.
70–80%
Typical cure rate for a first episode, all three options
2–3 days
Before most women notice clear improvement
50–70%
Recurrence within 12 months, regardless of which was used
That last figure is the one that matters most and is least often mentioned. Recurrence is common with every option, which is why the choice of first-line treatment is much less important than what happens if episodes keep returning. See recurrent BV for how repeat episodes are managed, and how long BV takes to clear up for what to expect during the course itself.
On pharmacy alternatives. Lactic acid gels such as CanesBalance are sold over the counter and can help with symptoms, but the UK VITA trial found them clearly less effective than metronidazole for clearing an active episode. Our guide to BV gels compared looks at these options in full.
Pregnancy, breastfeeding and recurrence
Three situations change the picture and need clinician involvement rather than an online order.
1
Pregnancy
Symptomatic BV in pregnancy is generally treated, usually with oral metronidazole, but always under the care of a clinician who knows you are pregnant. Do not self-treat or order online while pregnant.
2
Breastfeeding
Metronidazole passes into breast milk and can affect its taste. Vaginal preparations result in much lower exposure and are often preferred, but this should be a prescriber decision.
3
Repeated episodes
Three or more confirmed episodes in twelve months is managed differently — extended courses, suppressive twice-weekly gel and systematic trigger management, rather than repeating a standard course each time.
Order BV Treatment for Fast Relief
Complete a short online consultation and our GPhC-registered pharmacist independent prescribers will recommend the option that fits your circumstances.
Start a BV consultation →Frequently Asked Questions
Which BV treatment is most effective?
Oral metronidazole, Zidoval vaginal gel and Dalacin 2% cream all have broadly comparable cure rates for a first episode, typically quoted in the region of 70 to 80%. The choice is usually driven by tolerability, alcohol, contraception and personal preference rather than by a meaningful difference in effectiveness.
Which BV treatment can I use if I do not want to avoid alcohol?
Dalacin 2% cream contains clindamycin and carries no alcohol restriction. Both metronidazole tablets and Zidoval gel are metronidazole preparations, so alcohol should be avoided during the course and for 48 hours afterwards.
Which BV treatment is safe with latex condoms?
Metronidazole tablets and Zidoval gel do not affect latex. Dalacin 2% cream weakens latex condoms and diaphragms and they should not be relied on for contraception or protection during the course and for five days after the last application.
What is the shortest course of BV treatment?
Zidoval vaginal gel is the shortest standard course at five nights. Oral metronidazole is five to seven days and Dalacin 2% cream is seven nights. A single 2g dose of metronidazole exists but is less effective and is not routinely recommended in UK practice.
What if I cannot tolerate oral antibiotics?
The vaginal preparations are the appropriate alternative. Because far less drug reaches the bloodstream, Zidoval gel and Dalacin cream cause much less nausea and metallic taste than oral metronidazole while achieving similar cure rates.
Which BV treatment is used in pregnancy?
Symptomatic BV in pregnancy is usually treated with oral metronidazole, but this must be managed by a clinician who knows you are pregnant. Do not order treatment online or self-treat during pregnancy.
Can I switch treatment if the first one does not work?
Yes, and switching between drug classes is a recognised approach. If a full metronidazole course has not resolved symptoms, a prescriber may move you to clindamycin, or reconsider whether the diagnosis is correct. Do not repeat the same course without advice.
Completing the treatment
All three options are available from Access Doctor following an online consultation with a pharmacist independent prescriber. Tell us about alcohol plans, contraception and any previous courses in the consultation — those are the details that determine which one we recommend.
Bacterial vaginosis · Rx
Metronidazole 400mg Tablets
First-line oral antibiotic for BV, taken twice daily for five to seven days.
View product →Bacterial vaginosis · Rx
Zidoval Vaginal Gel
Metronidazole 0.75% gel applied nightly for five nights.
View product →Bacterial vaginosis · Rx
Dalacin 2% Cream
Clindamycin vaginal cream, a seven-night course with no alcohol restriction.
View product →Self-test · Pharmacy
Canestest Self-Test
Checks vaginal pH at home to help distinguish BV from thrush before you treat.
View product →References
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Bacterial vaginosis. 2025. cks.nice.org.uk
- Electronic Medicines Compendium. Zidoval 7.5mg/g Vaginal Gel — Summary of Product Characteristics. medicines.org.uk
- Electronic Medicines Compendium. Dalacin 2% Cream — Summary of Product Characteristics. medicines.org.uk
- Armstrong-Buisseret L, Brittain C, Hepburn T, et al. Lactic acid gel versus metronidazole for recurrent bacterial vaginosis: the VITA RCT. NIHR Health Technology Assessment, 2022. ncbi.nlm.nih.gov
- British Association for Sexual Health and HIV. National guideline for the management of vaginal discharge. bashh.org
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.