Generic medicines in Australia, and when to choose one

What is a generic medicine?

A generic medicine is another brand of a medicine that’s already sold. It contains the same active ingredient, the chemical that makes the medicine work. Other companies can make and sell it once the patent on the original brand has expired.

What can differ is everything else in the tablet. The inactive ingredients, which give a medicine its colour and taste, are often different, and a generic tablet or capsule can be a different size or shape. That’s why a new brand of a medicine you’ve taken for years can look nothing like the old one.

Is a generic as good as the original brand?

Yes. As well as having the same active ingredient, a generic has to be bioequivalent: take the same dose of either, and your body absorbs the same amount of the active ingredient over the same time. Companies show this in a study where volunteers take the original and, on a separate day, the generic, and blood tests compare how much of the medicine is absorbed and how fast.

The Therapeutic Goods Administration (TGA) allows a generic to be sold only if the evidence shows it’s bioequivalent. Generics meet the same standards of quality, safety and effectiveness as the original brand, wherever they’re made, and they have the same potential benefits and the same potential side effects.

Not every medicine has a generic. A newer medicine is often available only as the original brand until its patent runs out.

Why do some brands cost more?

The PBS subsidises a medicine up to the price of its cheapest brand. A dearer brand of the same medicine can carry a brand premium, an extra charge kept by the company that makes it, which you pay on top of the co-payment.

A brand premium is only allowed when another brand of the same medicine on the PBS has none. The premium doesn’t count towards your PBS Safety Net, and a 60-day script for a brand with a premium carries two premiums, one for each pack. There’s more on co-payments and the Safety Net in what a PBS prescription costs in 2026.

Can my pharmacist swap my brand?

Yes, without checking with your doctor, when all of these apply:

• you agree to the swap
• the PBS Schedule lists the two brands as interchangeable
• your doctor hasn’t marked the script “brand substitution not permitted”
• your state or territory’s law allows it.

Most PBS scripts are written for the active ingredient rather than a brand, which leaves the choice of brand to you and your pharmacist. You don’t have to accept a generic if you’re offered one. If you have an allergy, tell your pharmacist, in case it’s to one of a generic’s inactive ingredients; the Consumer Medicine Information leaflet lists them.

When might my doctor say no?

Your doctor can tick “brand substitution not permitted” on the script, and the pharmacist then has to supply the brand named. A doctor might do this if you could react badly to other brands. There may be other times your doctor recommends staying on one brand, so if you’re unsure about switching, ask your GP or pharmacist first.

A doctor may also name a brand without ruling out a swap, for example when a medicine has four or more active ingredients and naming each one isn’t practical.

What about biosimilars?

Biological medicines are made using genetically modified living cells. They include insulin, growth hormone and the monoclonal antibodies used for some autoimmune diseases and cancers. Because the process is so complex, a biological medicine can’t be copied exactly: even two batches from the same maker are never identical, though the differences are too small to matter clinically.

A biosimilar is a highly similar version of a biological medicine, sold once the original brand’s patent has expired. It meets the same regulatory standards and is equally safe and effective. If you already use the original brand, you can change to a biosimilar of the same form and strength, or back again, and it counts as the same ongoing treatment. Where the PBS Schedule marks a biosimilar as interchangeable, your pharmacist can offer it in place of the original, with your agreement, unless your doctor has ruled out substitution.

Where to ask

Your pharmacist can tell you which brands of your medicine are available, which carry a premium, and whether a swap is allowed on your script. To talk it through in person, find pharmacies near you or browse pharmacies by state.