Flagyl ER (Metronidazole) Extended-Release Tablets: Prices and Package Options

Flagyl ER is the extended-release oral tablet form of metronidazole, a nitroimidazole antibiotic used against susceptible anaerobic bacteria and certain protozoal organisms. We offer it in two strengths, 200 mg and 400 mg, with several pack sizes for each, so the real choice when you shop with us is which strength, which pack size, and which unit value suits the course you have been prescribed.

Price and choice overview

Before comparing numbers, it helps to see the choice as three linked decisions: the strength your course calls for, the pack size that covers that course without excessive leftover stock, and the unit value that follows from the pack size you pick. We price Flagyl ER in Australian dollars, and every pack we list is an extended-release tablet taken by mouth, not a different release type or route. The strength and dosing schedule must follow the directions for your specific treatment, while choosing between a 90-tablet pack and a 360-tablet pack changes how long a single order lasts and how far your money goes per tablet.

How do our package sizes affect value per tablet?

Unit value is simply the pack price divided by the number of tablets in it, and it typically improves as pack size increases, because packing and dispensing costs are spread over more tablets. We set out our current pack sizes, total prices, price per tablet, and the relative savings of larger packs in the comparison below so that you do not need to calculate this yourself.

Use this comparison alongside your expected treatment length. A larger pack can lower the price per tablet, but it is only genuine value if the tablets will be used within a reasonable time and before the expiry date printed on the pack. If your course is short, a smaller pack that matches it closely is often the more sensible choice, even if its unit price is slightly higher.

Strength, form, and quantity decisions

We offer Flagyl ER 200 mg in packs of 120, 180, 270, and 360 tablets, and Flagyl ER 400 mg in packs of 90, 120, 180, 270, and 360 tablets. Both strengths are extended-release oral tablets formulated to release metronidazole gradually. Extended-release and immediate-release metronidazole are not automatically interchangeable, and the dosing frequency depends on the exact product, indication, and directions provided for the course. The table below sets out the pack sizes available for each strength side by side, which is a different comparison from the pricing table above, since it looks purely at how many tablets come in each option rather than at cost.

Pack sizes by strength

The strength and daily dose you need are matters for whoever prescribes your treatment, but once that is decided, the pack size decision is mostly about how many tablets you want on hand and how that lines up with the price-per-tablet comparison shown earlier.

Brand, generic, and alternative context

Flagyl ER is a recognised brand name for extended-release metronidazole, and metronidazole itself is the active ingredient, belonging to the nitroimidazole class of antibiotics. Immediate-release metronidazole tablets are a related but distinct formulation, often used with different dosing schedules, and are not the product listed on this page. Other antimicrobials, such as clindamycin or tinidazole, are sometimes used for related anaerobic or protozoal infections, but they work differently or cover a different organism profile, and they are not extended-release metronidazole. If a prescriber has specifically written for Flagyl ER or extended-release metronidazole, the strength and pack size choices above are the ones that apply to that prescription.

• Flagyl ER: extended-release metronidazole in 200 mg or 400 mg tablets, used according to the directions for the exact product and indication.
• Immediate-release metronidazole: the same active ingredient in a different formulation, with potentially different dosing instructions.
• Clindamycin, tinidazole, and similar agents: different antimicrobials sometimes used for comparable infections, not metronidazole.

For a broader look at antibiotic options we carry, our Antibiotics range is worth browsing if your treatment plan involves more than one agent.

Established use and the product's role

Metronidazole as an active ingredient is established for treating infections caused by susceptible anaerobic bacteria and certain protozoa. Recognised uses across appropriate metronidazole formulations include bacterial vaginosis, trichomoniasis, giardiasis, amoebiasis, and various anaerobic bacterial infections affecting the abdomen, pelvis, skin, and other tissues. The extended-release oral formulation has an established adult role in bacterial vaginosis, but uses and regimens approved or established for immediate-release metronidazole should not automatically be applied to an extended-release tablet. Because the condition and exact formulation determine the strength, dose, and length of treatment, the role of this page is to help you match our available strengths and pack sizes to the course set for you rather than to suggest a dose.

Readers researching metronidazole for reasons beyond infection treatment, such as vaginal health concerns generally, may also find our Woman's Health category useful for related products.

How does Flagyl ER work?

Metronidazole is taken up by anaerobic bacteria and sensitive protozoa, where it is chemically reduced to reactive intermediates that damage microbial DNA, leading to cell death in susceptible organisms. The extended-release tablet is designed to release the drug gradually in the gastrointestinal tract. Extended-release metronidazole is generally taken on an empty stomach, at least 1 hour before or 2 hours after a meal, and the tablet should be swallowed whole rather than crushed, chewed, or split. Follow the directions supplied with the exact product and the regimen set for your condition. Full benefit typically develops over the course of treatment rather than immediately, and the complete course should be finished as directed, even if symptoms improve early, to reduce the chance of the infection persisting or recurring.

Important safety and interaction information

Metronidazole is generally well tolerated, but it carries some well-established precautions that are worth knowing before you start a course.

Common and notable effects

• A metallic taste, nausea, or mild stomach upset.
• Headache or dizziness.
• Dark or reddish-brown urine, which is usually a harmless colour change.
• Less commonly, confusion, visual disturbance, seizures, or tingling or numbness in the hands or feet; these warrant prompt medical review.

Who should be cautious

• People with a known hypersensitivity to metronidazole, other nitroimidazole medicines, or any formulation ingredient should not use it.
• Alcohol and products containing propylene glycol should be avoided during treatment and for at least 3 days after the final dose because unpleasant reactions such as flushing, nausea, vomiting, headache, and palpitations may occur.
• Metronidazole should not be used by someone who has taken disulfiram within the previous 2 weeks because serious neurological reactions can occur.
• Metronidazole can increase the effect of warfarin and similar anticoagulants, so anyone taking an anticoagulant may need closer monitoring. It can also interact with medicines including lithium and busulfan.
• Established prescribing information advises using metronidazole in pregnancy only when clearly needed, and breastfeeding is generally not recommended during a course because the drug passes into breast milk.
• Paediatric dosing and safety for this extended-release tablet specifically have not been established; this formulation is intended for adult use.
• Because dizziness, confusion, or visual disturbance can occur, driving or operating machinery should be avoided if these symptoms appear.

This is general safety information rather than a substitute for your prescriber's or our pharmacist's advice about your personal health history, other medicines, or specific course length.

Is a prescription required to order Flagyl ER from us in Australia?

Metronidazole is authorised for human medicinal use in Australia, and the extended-release tablet form is classified there as a prescription medicine. That classification describes how the medicine is regulated in Australia generally, separate from our own ordering process. For this listing, we do not require you to submit a prescription for us to accept your order, so you can place an order for Flagyl ER without providing one in advance. If you do have a prescription, our pharmacist-supported team can still take it into account; our online chat and email support are staffed every day of the week for questions about your order or about using this medicine appropriately.

Ordering, delivery, and receiving your order

Once you choose a strength and pack size, our checkout confirms the exact option selected, including the quantity and total price, before payment. We have supported customers from Australia and elsewhere since 2018, and our support team, reachable by email or online chat around the clock, includes pharmacist input for questions about dosing schedules, storage, or what to expect after your order is placed. After dispatch, we aim to get your pack to you in sound condition, and we recommend checking the pack on arrival for the expiry date and for any sign of damage to the container before you start the course.

• Select the strength and pack size based on the directions for your treatment course.
• Review the exact price and pack details at checkout before confirming payment.
• Contact our support team by email or chat if you have questions before or after ordering.
• Check the pack on arrival and store it correctly before use.

Storage and making the most of your pack

Store Flagyl ER tablets at 20°C to 25°C, in a tightly closed, light-resistant container, and protect them from light. If you choose a larger pack for better unit value, make sure your storage conditions and the time until the tablets will realistically be used still fall within the labelled expiry period; unit value only translates into real savings when the whole pack is used appropriately rather than left to expire.

Making the value-based decision

Weighing price against practical need is the heart of choosing between our Flagyl ER options. The 200 mg and 400 mg strengths should not be substituted for one another or combined to create a regimen unless specifically directed, while a larger pack size generally improves the price per tablet shown in the comparison above. The most sensible choice balances three things: the strength directed for you, a pack size that reasonably matches your expected course and storage plans, and the unit value you can see in the table, rather than selecting purely on the lowest headline price. When those three line up, you get both an appropriate supply and the most efficient use of what you spend with us.