Bioequivalent and Generic Medicines Flashcards
What is bioequivalent (generic) medicine
An identical version of an already registered medicine that produces similar plasma concentrations of the active ingredient
What is biosimilar medicine?
A highly similar version of an already registered biological medicine (the reference biological medicine) that has been assessed to be highly similar to the reference biological medicine in terms of safety, effectiveness, physicochemical characteristics, biological characteristics, and immunological characteristics
What does the application for a generic product in Australia include?
A bioequivalence study versus the originator brand obtained in Australia
> aim of establishing whether two or more formulations of the same drug are equivalent in terms of the rate and extend of absorption of the drug (or active moiety) into the systemic circulation
What things to do generic medicines have to meet and maintain
Must meet and maintain TGA quality assurance, safety and effectiveness standards
- Manufacturing facility and manufacturing process
- Ingredient
- Product
When can a medicine undergo susbstitution?
- If prescriber has not indicated ‘brand substitution not permitted’ and they have permission from the patient
- Applies most often to generic medicines/biological medicines with a biosimilar that has been recommended by the pharmaceutical benefits advisory committee (PBAC) as substitutable
- Substitutable medicines are marked in the schedule of pharmaceutical benefits with an ‘a’ (a-flagged)
What does the term interchangeability mean?
If two or more medicines are considered interchangeable –> the prescriber may choose to prescribe either of the medicines for a patient to treat the same condition –> pharmacist must dispense as prescribed
What do brands flagged ‘b’ mean?
Brands flagged B are also equivalent but indicate that it is not known if there is equivalence between brands marked a and those marked b
When is substitution permitted?
- Drug is prescribed without the indication of a brand e.g. atorvastatin
- Product is ‘a’ flagged PBS medicine with a bioequivalent (generic) OR biosimilar medicine without reference to the prescriber
- Obtained patient consent
- Confirmed on the prescription that the prescriber has not prohibited substitution, before substituting medicines
What to consider when informing patients about generic medicines?
- Age, cognitive function, mental acuity, vision
- Number of medications and complexity of patient’s regimen
- Non-English speaking background
- Narrow therapeutic index
When should caution be required?
Medicines with a narrow therapeutic index
- Patients with well-control epilepsy shouldn’t have their epileptic medicine substituted –> if brand substitution is considered necessary –> the prescriber’s advice should be sought first
Allergy, intolerance or concern to exposure
- coloring agent, lactose, gluten, gelatin
Possible negative impact on adherence
- people with a mental illness
Risk of confusion, anxiety or harm
Different device used to administer the medicine
What are biosimilars?
A biosimilar is a version of an already registered biological medicines that has a demonstrated similar physicochemical, biological and immunological characteristics, efficacy and safety
- Biologic drugs are enormous structures, far too complex producing using synthetic approaches
Process for bioequivalence needs to
- Acknowledge biologicals are very complex molecules
- Acknowledge processes are proprietary used to manufacture them
- Acknowledge there will be some differences in the processes used by manufacturers
How does the TGA test that both biosimilar and reference medicine will have similar characteristics?
Comparability studies
- Physiochemical
- Biological
- Immunological
- Efficacy and safety
