Flagyl ER Extended-Release Tablets: Prices and Pack Options

We stock Flagyl ER as an oral, extended-release tablet built around metronidazole, a long-established nitroimidazole antibiotic. We offer it in two strengths, 200 mg and 400 mg, and across a range of pack sizes, so the real choice in front of you is not just whether to order Flagyl ER, but which strength, which quantity, and which pack represents the best value for the course of treatment your prescriber has set out. Each pill counted in the package options is one extended-release tablet.

Because an extended-release tablet is designed to release metronidazole over time, the strength you need, the number of pills per pack, and how those packs compare in unit value all matter. This guide walks through the pack sizes we currently offer, how to read their value, and how strength, course length, storage and expiry all feed into the pack you should select at checkout.

Comparing Pack Sizes and Unit Value

Unit value is simply the price of each pill once you divide the total pack price by the number of pills inside it. It is a useful way to compare our pack sizes side by side, but it is only one part of a sensible decision: the pack you choose should still match the strength and quantity agreed with your prescriber rather than being driven by price alone.

The comparison above sets out the exact prices, per-pill value and relative savings across our current 400 mg Flagyl ER pack sizes. Larger packs may have a lower price per pill, but that does not make an unnecessary quantity better value. Choose a package only when it is appropriate for your confirmed treatment plan, and do not buy or retain surplus antibiotics for a possible future infection without clinical advice. Check the expiry date on the pack when it arrives and store the tablets at 20°C to 25°C in a tightly closed, light-resistant container protected from light.

Which Flagyl ER Strength and Pack Size Fits Your Course?

We offer Flagyl ER in 200 mg and 400 mg tablets, and the pack sizes available differ slightly between the two strengths. The table below sets out the pill quantities we currently hold for each strength, so you can see at a glance which sizes exist before weighing them against the unit-value comparison above.

What shapes your ideal pack size

• Prescribed strength: your prescriber will have specified the required strength and regimen; the product you order should match those instructions rather than being substituted to chase a lower unit price.
• Prescribed quantity: metronidazole regimens vary by infection, formulation and patient. Choose a pack only if it supports the treatment plan you have been given, and ask a pharmacist what to do if the smallest offered pack exceeds the prescribed quantity.
• Future treatment: do not use leftover metronidazole for a new infection or assume that a repeat course will be appropriate. Similar symptoms can have different causes and may require a different medicine or regimen.
• Storage conditions at home: a tightly closed, light-resistant container kept at 20°C to 25°C is needed for any pack size, so check that you have somewhere suitable before ordering.

Flagyl ER Within the Wider Antibiotic Picture

Flagyl ER delivers metronidazole, a nitroimidazole antibiotic, in an extended-release tablet rather than an ordinary immediate-release one. The extended-release design changes how the medicine is released, so it should not be assumed to be interchangeable dose for dose with an immediate-release metronidazole product. The tablet should be swallowed whole rather than split, crushed or chewed.

Other treatments used for anaerobic infections, such as clindamycin, vancomycin and fidaxomicin, work through different mechanisms and are used in different clinical situations, including some forms of Clostridioides difficile infection where metronidazole is no longer first-line. For infections caused by different organisms, a penicillin-class antibiotic such as Amoxil may be more appropriate; your prescriber is best placed to decide which class suits your specific infection. If you are exploring antibiotic options more broadly, you can also browse our Antibiotics range.

What Is Metronidazole Used For?

Metronidazole is an established treatment for susceptible anaerobic bacterial and certain protozoal infections. The appropriate formulation and regimen depend on the condition being treated, so not every recognised use of metronidazole necessarily applies to every extended-release product. Uses of metronidazole can include:

• Infections caused by susceptible anaerobic bacteria, including some abdominal, pelvic and skin infections.
• Bacterial vaginosis and certain other gynaecological infections where anaerobic organisms are implicated.
• Protozoal infections such as intestinal amoebiasis and trichomoniasis.
• Use as part of combination regimens for some gastrointestinal infections under specialist direction.

Readers researching gynaecological infections may also find our Women's Health range useful. Metronidazole is authorised for human medicinal use in the United Kingdom; suitability of this particular extended-release product, strength and regimen should be confirmed for the infection being treated.

How Does Metronidazole Work, and How Should You Take Flagyl ER?

Metronidazole is activated within susceptible anaerobic bacteria and certain protozoa, where it disrupts DNA and other essential cellular processes, leading to the death of the organisms responsible for the infection. The extended-release formulation releases the medicine differently from an immediate-release tablet, but the required dose frequency still depends on the specific product instructions and prescribed regimen.

Swallow Flagyl ER tablets whole with water; do not split, crush or chew them because damaging the tablet may alter the release mechanism. Follow the supplied leaflet and your prescriber's directions about dose timing and whether to take the tablet in relation to food, as administration instructions can differ between formulations. Avoid alcohol during treatment and for at least 48 hours after the last dose because the combination may cause flushing, nausea, vomiting, headache or palpitations. Complete the prescribed course unless a healthcare professional tells you to stop, even if symptoms begin to improve earlier.

Safety Considerations and Interactions to Keep in Mind

Metronidazole is generally well tolerated, but it carries established safety points worth keeping in mind alongside the separate safety information shown elsewhere on this page:

• Do not take it if you have a known hypersensitivity to metronidazole, another nitroimidazole or an ingredient in the tablet.
• Common effects include a metallic taste, nausea, loss of appetite and occasional headache.
• Less common but notable effects include dizziness, drowsiness, confusion or visual disturbance; do not drive or operate machinery if you are affected.
• Dark urine can occur and is usually harmless, but seek medical advice about a new rash, severe or persistent gastrointestinal symptoms, seizures, confusion, or numbness and tingling.
• Tell your prescriber about significant liver disease, neurological or blood disorders, pregnancy or breastfeeding. Paediatric use requires age- and weight-specific prescribing, and an intact extended-release tablet may not suit a child who cannot swallow it safely.

Interactions to flag with your pharmacist

Metronidazole can interact with warfarin and other anticoagulants, lithium, disulfiram, and some anti-epileptic medicines. It should not be combined with disulfiram or taken close to disulfiram use. If you take any regular prescribed medicine, mention it to our pharmacist team or your own prescriber before starting Flagyl ER so that any necessary adjustment or monitoring can be arranged.

Do You Need a Prescription for Flagyl ER in the UK?

Metronidazole extended-release tablets are classified as a prescription-only medicine in the United Kingdom, reflecting the dosage form's regulatory status rather than our checkout process. Separately, our ordering policy does not require you to submit a prescription for us to accept your order, so you can place an order for Flagyl ER with us without a prescription in hand. We still encourage anyone starting this medicine to confirm suitability, strength and course length with a doctor or pharmacist because prescription classification and our ordering requirement are separate matters.

Ordering, Delivery and Support From Us

We have been running MedicalBrandNames since 2017, and our checkout, packing and delivery process for Flagyl ER follows the same straightforward steps we use across the rest of our catalogue:

1. Choose your strength, 200 mg or 400 mg, and a pack size from the options shown on this page.
2. Confirm the quantity and review the package-value comparison before completing payment in pounds sterling.
3. We pack your tablets for dispatch to the postcode you provide at checkout.
4. Our support team is available 24/7 by email, online chat or phone, with access to a pharmacist if you have questions before or after ordering.

We aim to make choosing between pack sizes as clear as the ordering process itself, so that you can compare the available options against the strength and quantity in your treatment plan.

Bringing Price, Pack Size and Suitability Together

Choosing a Flagyl ER option comes down to matching three things: the prescribed strength, a package quantity appropriate for your confirmed treatment plan, and the unit value shown in the comparison above. A larger pack may lower the per-pill cost, but it is not better value if the extra tablets are unnecessary or expire unused. Store the tablets correctly at 20°C to 25°C and protected from light, and never save leftovers for self-treatment of a later infection. If you are unsure how the offered strengths or package quantities relate to your instructions, our pharmacist-supported team can explain the options, while your prescriber remains responsible for determining the appropriate regimen.