Generic vs Branded Medicines: What You Need to Know

What Are Generic Medicines?

A generic medicine contains the same active ingredient, in the same dose, as the branded (originator) product. When a drug's patent expires (typically after 10-15 years), other manufacturers can produce generic versions. In the UK, around 80% of NHS prescriptions are dispensed as generics.

Are Generics As Good As Branded?

In the vast majority of cases, yes. To be licensed, a generic must demonstrate "bioequivalence" — meaning it's absorbed into the body at the same rate and to the same extent as the original. The MHRA requires that generics perform within 80-125% of the reference product in bioequivalence studies.

When Does Brand Matter?

For a small number of medicines, switching between brands can cause problems:

Narrow Therapeutic Index Drugs

These are medicines where small differences in blood levels can have significant clinical effects:

Modified-Release Formulations

Medicines with "MR", "XL", "SR", or "Retard" in the name are designed to release the drug slowly over time. Different brands may have different release profiles, so switching should be done with medical supervision.

During Shortages

If your usual brand is unavailable:

• For most medicines: a generic is perfectly fine and your pharmacist can dispense it without a new prescription
• For narrow therapeutic index drugs: speak to your prescriber before switching brands
• For epilepsy medications: follow MHRA Category guidance
• If you switch and notice different effects: report via the MHRA Yellow Card scheme

Cost Difference

On the NHS, you pay the same prescription charge regardless of whether you receive generic or branded. On private prescriptions, generics are usually significantly cheaper.

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