Flagyl ER (Metronidazole) Extended-Release Tablets: Prices, Strengths and Pack Sizes

Flagyl ER is the extended-release tablet form of metronidazole, an established nitroimidazole antibiotic taken by mouth. We offer it as 200 mg and 400 mg tablets, and the real decision for most customers is not whether to use Flagyl ER, but which strength matches the treatment a prescriber has set out and which offered pack is appropriate for that plan. This guide walks through the pack options, their value, and what to expect when you order Flagyl ER from us in Australia.

Flagyl ER: the choices behind the price

Before looking at figures, it helps to see what actually varies between our Flagyl ER listings. Three things change the price you pay: the tablet strength (200 mg or 400 mg), the number of tablets in the pack, and the resulting price per tablet. The active ingredient, extended-release form, and oral route remain the same across the listed packs, so the choice should be based on the prescribed strength and a medically appropriate quantity rather than price alone.

The lowest total price is not necessarily the best fit, and the lowest unit price does not make an otherwise unnecessary quantity appropriate. Confirm the intended dose, treatment duration, and number of tablets before comparing package value. Do not buy extra antibiotic tablets for unassessed future symptoms or assume that a recurrence should be treated with the same medicine.

Available pack sizes and unit value

We currently list 200 mg tablets in packs of 120, 180, 270 and 360, and 400 mg tablets in packs of 90, 120, 180, 270 and 360, all priced in Australian dollars. Larger packs may have a lower price per tablet, so it is useful to check unit value rather than looking only at the total price. The comparison below sets out exactly what each current 400 mg pack costs in total and per tablet, along with the relative saving available across the listed quantities.

Use this comparison alongside a documented treatment plan. Package value is most relevant when the full quantity has a legitimate intended use and can be stored correctly until needed. If a pack contains more tablets than the prescribed course requires, ask a pharmacist what to do with the remainder rather than retaining it for self-treatment or sharing it with someone else.

Expiry also matters when comparing quantities. Check the expiry information supplied with the pack after delivery, keep the tablets in their original container, and avoid treating a theoretical long-term unit saving as more important than appropriate antibiotic use.

How do you choose between the 200 mg and 400 mg tablets?

The right strength depends on the prescribed dose, not on price alone. A prescriber may specify how many tablets are needed to make up each once-daily dose, and that direction determines how quickly a pack will be used. Do not substitute one strength for another or change the number of tablets without professional advice. The table below shows the pack sizes we hold for each strength so you can check the available combination before ordering.

• Match the strength to the directions supplied by the prescriber or pharmacist.
• Calculate quantity from the prescribed number of tablets per day and the treatment duration.
• Remember that strength and quantity are independent choices: a larger pack does not contain a higher-strength tablet.

Because these are extended-release tablets, they should not be split to create an intermediate strength unless the specific product information and a pharmacist explicitly permit it. Crushing or chewing the tablets can interfere with their modified-release properties.

Flagyl ER as a brand, and where metronidazole fits among other options

Flagyl ER is a brand-name extended-release presentation of metronidazole, distinct from standard immediate-release metronidazole tablets, which have different release characteristics and dosing schedules. They should not be treated as automatically interchangeable. Other nitroimidazole antibiotics, such as tinidazole and secnidazole, and non-nitroimidazole options such as clindamycin, cover overlapping but not identical situations. Differences in indication, dosing, interactions, pregnancy considerations, and organism susceptibility mean that switching is a clinical decision rather than a simple price substitution.

If a prescriber has specifically directed the use of extended-release metronidazole, Flagyl ER is the presentation in this listing. For infections that require a different antibiotic, you can browse our Antibiotics range while following advice about the appropriate treatment.

What is Flagyl ER used for?

Metronidazole in this extended-release form is established for once-daily oral treatment of bacterial vaginosis in adult women, a common vaginal condition associated with an imbalance in the normal bacterial environment. The extended-release design supports a once-daily schedule, although the number of tablets needed for the prescribed daily dose depends on the directions and tablet strength.

• Bacterial vaginosis in adult women is the established indication for this extended-release presentation.
• Other anaerobic bacterial and certain protozoal infections may be treated with metronidazole generally, but these commonly involve immediate-release formulations and different dosing patterns.

Metronidazole does not treat viral infections or fungal conditions such as vaginal candidiasis. Similar symptoms can have different causes, so persistent, recurrent, or worsening symptoms should be assessed rather than managed by repeating leftover treatment. For general navigation to related products and information, you can also browse our Women's Health range.

How does extended-release metronidazole work, and how should it be taken?

Metronidazole enters susceptible anaerobic organisms and is converted into reactive compounds that damage DNA and disrupt essential cellular processes. Its activity depends on the organism and infection site, which is why it is not a general-purpose treatment for every infection. The extended-release formulation releases metronidazole over time and supports once-daily dosing rather than the divided schedules commonly used with some immediate-release regimens.

Flagyl ER tablets are generally taken on an empty stomach, roughly one hour before or two hours after a meal, because food can alter exposure to the extended-release medicine. Follow the directions supplied with the product and take each dose at about the same time each day. Tablets should be swallowed whole rather than split, crushed, or chewed, as damaging the tablet can interfere with extended release.

Treatment for bacterial vaginosis with an extended-release regimen commonly runs for about seven days, but the exact dose and duration must come from the treating professional. Complete the prescribed course even if symptoms improve earlier. If a dose is missed, follow the product instructions or ask a pharmacist; do not automatically double the next dose. Seek further advice if symptoms fail to improve, become worse, or return after treatment.

Safety considerations, side effects and interactions

Metronidazole is generally well tolerated, but it carries effects and precautions worth knowing before starting a course.

Common side effects

• Nausea, a metallic taste in the mouth, reduced appetite, or mild stomach upset.
• Headache or dizziness.
• Darkened urine, which can be a harmless effect of the medicine's metabolism.

Important interactions and precautions

• Alcohol should be avoided during treatment and for the period advised after the final dose, as the combination can cause flushing, nausea, vomiting, and a rapid heartbeat.
• Metronidazole can increase the effect of warfarin and other anticoagulants, so people taking blood thinners may need closer monitoring.
• Lithium levels can rise during metronidazole treatment. Medicines including phenytoin and phenobarbital can also alter metronidazole handling, while recent disulfiram use can cause a serious interaction.
• Known hypersensitivity to metronidazole, other nitroimidazoles, or formulation ingredients is a contraindication, and the extended-release tablet is not established for paediatric use.
• Breastfeeding is generally not advised during a course because metronidazole passes into breast milk in meaningful amounts. Pregnancy also requires an individual benefit-risk discussion.

Dizziness, confusion, hallucinations, or visual disturbances can impair driving and the use of machinery. Stop the activity and seek advice if these occur. New numbness or tingling, poor coordination, seizures, a severe rash, facial swelling, or other signs of a serious reaction require prompt medical attention.

Routine laboratory monitoring is not usually needed for every short course, but it may be appropriate during prolonged or repeated treatment or for people with significant liver, kidney, blood, or neurological conditions. Anyone who is pregnant, breastfeeding, taking regular medicines, or managing a complex medical condition should discuss the treatment with a prescriber or pharmacist before starting.

Do you need a prescription to order Flagyl ER from us in Australia?

In Australia, metronidazole extended-release tablets are classified as a prescription medicine, reflecting the local classification of this dosage form. That regulatory classification is separate from our own ordering process: we do not require you to send us a prescription before we accept an order for Flagyl ER, so you can place an order without a prescription in hand. This describes how our checkout works and does not change the medicine's prescription classification in Australia. Treatment should still be based on appropriate medical advice.

Ordering, dispatch and delivery

We have operated our online catalogue since 2017, and our support team is available 24/7 by email, online chat, and phone, with a pharmacist on hand to answer questions about your order. Placing an order for Flagyl ER follows the same straightforward process as the rest of our catalogue.

1. Choose the prescribed strength and an appropriate pack size from the options on the product page.
2. Complete checkout with your delivery details and preferred payment method.
3. Our team packs and dispatches the order, with support available if you have questions about timing or delivery.

Check your strength, quantity, packaging, and expiry information when the order arrives. Store the tablets at 20°C to 25°C in their original, tightly closed, light-resistant container and protect them from direct light. Keep all medicines out of reach of children, and ask a pharmacist how to dispose of tablets that are expired or no longer required.

Choosing the right pack for your situation

Working out the best-value Flagyl ER option means weighing the unit price shown in the comparison against the prescribed strength, the number of tablets genuinely required, storage conditions, and expiry. A larger pack can lower the price per tablet, but that saving is meaningful only when the quantity has an appropriate planned use. It should not be used as a reason to extend a course, repeat treatment without assessment, share antibiotics, or retain unnecessary tablets for a possible future infection.

The practical approach is to confirm the strength, daily directions, and treatment duration first, then compare the offered packs. If every available pack contains more than the current course requires, choose on the basis of professional advice and our available options rather than assuming that the largest pack provides the best overall value.