When you're handed a prescription for paracetamol and the pharmacist dispenses 'acetaminophen' — or your ibuprofen comes in a box you don't recognise — it can be confusing. Here's what you need to know about generics.
What makes a medicine generic
A generic medicine contains the same active ingredient, at the same dose and strength, as the original brand-name version. It must meet the same regulatory standards for quality, safety and efficacy. The differences are in the inactive ingredients (fillers, dyes, coatings) and, usually, the price.
Generic medicines are typically 20–80% cheaper than brand names because the manufacturer doesn't recoup the cost of original clinical trials. Most countries' healthcare systems actively encourage generic prescribing for this reason.
When generics and brands can differ
- Formulation differences — different coatings or release mechanisms may affect how quickly the drug is absorbed
- Narrow therapeutic index drugs — medicines like lithium, warfarin and phenytoin, where small concentration changes have large clinical effects; some doctors prefer the same brand for consistency
- Allergy to an inactive ingredient — very rarely, a patient is allergic to a dye or filler in a specific generic formulation
What to do
If your prescription is dispensed as a different-looking medicine than usual, check with the pharmacist that it's the same drug and dose before taking it. If you have a strong preference for a specific brand — perhaps because a generic has caused a previous reaction — ask your prescriber to specify 'brand only' on the prescription.