Substituting scarce medicines

On occasion a pharmacist may be unable to dispense a prescription medicine because the medicine is affected by a shortage. This often means the patient has to try to source the medicine from other pharmacies or go back to their prescriber for a new prescription for an alternative medicine. Any delay in accessing their medicine risks disrupting the patient’s treatment which could affect their health.

To avoid delays in providing medicines to patients and relieve workload pressure on prescribers and pharmacists Serious Scarcity Substitution Instruments (SSSIs) were introduced to allow community pharmacists to substitute specific medicines without prior approval from the prescriber. Pharmacists are, however, required to notify the prescriber after substitution.

What is a Serious Scarcity Substitution Instrument or SSSI?

When the TGA declares a ‘serious scarcity’ of a medicine, an SSSI is made specifying the substitutable medicine(s) that pharmacists are permitted to dispense in substitution for the scarce medicine. The SSSI also specifies the circumstances in which that substitution is permitted.

SSSIs are made when there is a significant risk of adverse health consequences for Australian patients if those patients are unable to take the scarce medicine, and there is a suitable substitute medicine available. SSSIs are made for a defined period and may be revoked sooner.

What is a serious scarcity of a medicine?

The TGA can declare a serious scarcity of a medicine when there is a supply disruption of a particular medicine and demand cannot be met by the total stock available. The total stock available includes stock levels of all available brands of the medicine or an overseas alternative medicine approved for supply under section 19A of the Therapeutic Goods Act 1989.

A serious scarcity of a medicine can be declared when either or both of the following apply:

• the supply of the medicine in Australia is not currently meeting demand
• there is an imminent risk that supply of the medicine in Australia will not or will not be likely to meet demand

Supply disruptions do not need to affect the whole of Australia for a serious scarcity to be declared.

Identifying the need for an SSSI

We work closely with sponsors, wholesalers and key stakeholders to monitor the ongoing supply of medicines for Australian patients. This enables early identification of potential disruptions to medicine supply.

Once a medicine has been identified as being at risk of serious scarcity, we make an assessment to determine whether an SSSI is a suitable strategy to mitigate the shortage.

We evaluate the appropriateness and availability of potential substitutable medicines, assess the risk of adverse health consequences if access is delayed and identify vulnerable population groups affected by the medicine shortage.

How substitute medicines are determined

When we determine that an SSSI may be a suitable way to help manage the shortage, we assess which medicines might be appropriate alternatives. Then we check with the sponsors of those medicines that there is enough supply to cover the demand for the scarce medicine. If the alternatives are suitable and there is sufficient supply, they are put forward as potential substitute medicines.

When determining whether substitute medicines are suitable, we liaise with TGA medical officers, relevant clinical groups, specialist medical colleges and health professional societies. We also confirm the proposed dose schedules and specific conditions with these experts.

Substitute* medicines for a scarce medicine will usually be:

• tablets/capsules of lower or higher strength
• other dose forms containing the same active ingredient (for example, a capsule instead of a tablet, or a syrup or suspension)
• an immediate-release form in place of a sustained/extended-release version and vice versa
• the same active ingredient, but with a different salt.

If a fixed-dose combination is not be available, the two or three medicines that make up the combination can be dispensed individually.

Only substances included in Schedule 4 to the current Poisons Standard can be considered as a substitute for a scarce medicine.

*Substitute medicines are referred to as ‘substitutable’ medicines in the SSSI.

How to substitute with lower-strength tablets or capsules for SSSIs

Item 5 of the general permitted circumstances section of every SSSI directs the pharmacist to give enough substitute medicine to cover the same total dose and length of treatment as in the original prescription, including when a medicine is being substituted with multiples of a lower-strength medicine.

Therefore, if the original script is for 60 x 4 mg tablets (total 240 mg) and the allowed substitute medicine is available in 1 mg tablets, the pharmacist should dispense 240 of the 1 mg tablets in total.

Or, if the original script is for 60 x 4 mg tablets (total 240 mg) and the allowed substitute medicine is available in 2 mg tablets, the pharmacist should dispense 120 of the 2 mg tablets to make a total of 240 mg.

This total dose must be dispensed in all cases. At times, the pharmacist may have to open a new box of the substitute medicine and add a partial quantity to make up the necessary total dose.

When substituting medicines, the pharmacist must provide written dosing instructions to the patient or their carer to support the quality use of medicines by minimising the chance of confusion and error.

PBS requirements for SSSIs

When dispensing a substitute medicine, the pharmacist should use the Pharmaceutical Benefits Scheme (PBS) item code that appears on the PBS SSSI page - external site. The substitute medicine will have the same restriction criteria as the scarce medicine.

When the required quantity of the lower-strength substitute medicine is more than the maximum PBS quantity allowed, the pharmacist should use the authority prescription number specified for the medicine on the PBS SSSI page - external site.  

More information is available on the PBS SSSI page - external site, which also has a link to a helpful FAQ document - external site.

Communication about SSSIs

Details of the substitution are drafted into a legislative instrument, the SSSI, and published on the Federal Register of Legislation.

We also share information on the TGA website, social media, email alert service and through a wide range of partner organisations including relevant health professional bodies, patient/consumer groups and industry peak bodies.

You can subscribe to the Medicine Shortages alert service or follow us on our social media channels to find out about new SSSIs and other important medicine shortages information.

Monitoring SSSIs

We continue to monitor the need for and safety of the SSSI. If the serious scarcity is resolved, or safety concerns are identified, we may revoke the SSSI before its end date.

Reporting problems with an SSSI

Consumers and health professionals are encouraged to report problems with medicines or vaccines. The report should mention the problem relates to an SSSI. Your report will contribute to the TGA's monitoring of the safety of the SSSI.

The TGA cannot give advice about an individual's medical condition. We encourage you to talk with a health professional if you are concerned about a possible adverse event associated with a medicine or vaccine.

Legislative basis for SSSIs

Under section 30EK of the Therapeutic Goods Act 1989 - external site (the Act), under certain conditions, the Minister for Health can make a legislative instrument to:

• declare that there is a serious scarcity of specified medicine (the scarce medicine) across the whole or a specified part or parts of Australia; and
• specify the medicine (the substitutable medicine) that pharmacists are permitted to dispense in substitution for the scarce medicine and specify the circumstances in which that substitution is permitted.

Publication of an SSSI allows pharmacists to dispense the substitutable medicine under the conditions described in the instrument, even if the state or territory legislation would normally prevent this from occurring.

Full details of the substitution provisions are described in sections 30EK and 30EL and subsections 4(1) and 57(10)(AA) of the Act - external site. There are currently no related provisions included in the Therapeutic Goods Regulations 1990 - external site.

SSSIs replace the Serious Shortage Substitution Notices published on the TGA website throughout 2020 to ensure fast and consistent implementation across all states and territories.