Pharmacists in Australia have been able to substitute bioequivalent alternatives since 1994 – but problems are common and potentially serious, a Healthed poll has found.
Nearly half of GPs (46%) could count at least one time where a brand substitution by a pharmacist had been problematic in the previous 12 months, with many citing multiple occasions, according to a national Healthed survey with more than 2000 GP respondents in April.
Two thirds of more than 900 GPs who had encountered such a scenario said one or more of these substitutions had the potential to significantly impact their patient’s health or safety.
Four out of 10 GPs in the survey had one or more patients receive a generic brand from their pharmacist despite them explicitly stating on the script that substitutions are not permitted.
Confusion – sometimes resulting in medication errors – was the most common problem GPs mentioned arising from a pharmacist-initiated brand swap.
GPs described patients not recognising a substituted medication as the same drug, leading to missed doses, double dosing, or stockpiling. Elderly patients, those on polypharmacy, and non-English speakers were especially vulnerable.
Several doctors said that for various reasons – including thinking the pharmacist had dispensed the wrong one – patients did not take the medication at all.
Around one in five of more than 500 GPs who described the problems they’d encountered said they had patients experience reduced efficacy and poorer clinical outcomes.
GPs cited many examples. These included:
“With antidepressants, especially escitalopram — different brands affect mood adversely — patients reported feeling depressed when changed to a generic,” one GP said, while others described similar experiences.
Concerns about differences between brands of thyroid medication have also been raised by the Australian Thyroid Foundation. CEO Beverley Garside told Healthed they often get complaints from people who are not well, and upon questioning, learn their medication brand has been changed by a pharmacist.
On its website, the Australian Thyroid Foundation states that patients who are stable on a particular brand, “should not change brands for any reason, unless your thyroid treating doctor has recommended a change for a medical reason.” They recommend that if their particular brand is not available at the pharmacist, patients should request it be ordered and double check they’ve been given the correct brand before they leave. They also note that “Doses and brands should not be interchanged.”
Several doctors said patients had experienced allergic reactions when the brand was switched.
“Lactose used as an excipient in the substituted brand caused bad abdominal cramps and diarrhoea in a patient who is very lactose sensitive,” one GP described.
“A generic buprenorphine patch was supplied and patients developed a skin irritation,” another said.
Formulation and administration issues were also noted, such as a patient being given tablets when they are only able to swallow capsules, problems using some generic forms of vaginal estradiol because of “inferior quality of the applicator,” as well as difficulty halving some brands of tablets, or swallowing due to the size.
In other cases, the brand change didn’t have a clinical implication, but wasn’t in the patient’s best interest, for example substituting Wegovy for Ozempic which cost more.
While it is generally not permitted to override when a doctor indicates that brand substitutions are not permitted, there are exceptions, a spokesperson from the Department of Health, Disability and Ageing confirmed to Healthed.
Full response from the Department of Health, Disability and Ageing’s spokesperson:
“Under the Pharmaceutical Benefits Scheme (PBS), pharmacists may only substitute a prescribed brand in accordance with the National Health Act 1953 and PBS listing requirements. This includes that the alternative is an approved equivalent brand, the patient consents, and the prescriber has not indicated that substitution is not permitted.
Where a prescriber indicates “no substitution”, subsection 103(2) of the Act makes it an offence for a pharmacist to supply an alternative brand. This reflects the importance of maintaining the prescriber’s clinical judgement in determining that a specific brand is required.
Limited exceptions apply. Subsection 103(2A) allows substitution in defined circumstances, including where the Therapeutic Goods Administration (TGA) has issued a legislative instrument under the Therapeutic Goods Act 1989, such as Serious Scarcity Substitution Instruments (SSSIs) in response to a medicine shortage. These instruments define when pharmacists can substitute a different medicine without prior prescriber approval and sets out conditions of supply. Substitution outside these authorised pathways is not permitted.
For substitutions made under the SSSIs, the pharmacist must also inform the PBS prescriber who wrote the prescription, in writing, that the substitution has been made. The information must be provided within 72 hours after the supply.
Brand substitution under the PBS is generally limited to medicines assessed as bioequivalent and listed as equivalent brands. Biosimilar substitution is subject to specific regulatory and PBS arrangements. Certain medicines, including those with a narrow therapeutic index, are subject to tighter controls reflecting patient safety considerations.
Pharmacists may substitute bioequivalent and biosimilar medicines where the PBS lists them as substitutable (for example, with an ‘a’ flag in the PBS Schedule).
The important points here are that substitution depends on PBS interchangeability status, not whether the product is a generic or a biosimilar, and that all substitutions remain subject to normal rules, such as patient consultation and any “brand substitution not permitted” direction from the prescriber.
Please note, the PBS Schedule itself is not the legal backing, but it should align with the National Health (Listing of Pharmaceutical Benefits) Instrument, specifically Schedule 5—Schedule equivalent groups of brands of pharmaceutical items.
For further reference, https://www.pbs.gov.au/info/general/faq:
On the PBS website, substitutable brands are listed with either an ‘a’ or ‘b’ flag to indicate their interchangeability.
Jurisdictional initiatives, such as expanded substitution arrangements in Queensland, operate alongside but do not override PBS requirements for subsidised medicines. The changes to prescribing in Queensland to allow pharmacist led substitutions impact that state’s regulation on dispensing by the Queensland Government, which is separate to the Commonwealth legislation. Medicines substituted by pharmacists under this regulation are not subsidised or regulated under the Pharmaceutical Benefits Scheme (PBS). This means patients will need to pay the private prescription price for the medicine.”
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