Shortage of metformin modified-release 500mg (multiple brands)

TGA publishes Serious Shortage Substitution Notice 

The Therapeutic Goods Administration (TGA) was notified of current shortages for multiple brands of metformin modified-release 500mg tablets (also known as extended-release or XR tablets) and published a Serious Shortage Substitution Notice on 13 May 2020.

The shortages are expected to continue until 5 June 2020 at the earliest.

Metformin is a prescription drug used to treat type 2 diabetes.

In order to reduce the impact of this shortage on patients, the TGA has issued a Serious Shortage Medicine Substitution Notice for metformin modified-release 500 mg (pdf,47kb).

The notice specifies substitutions that pharmacists may make for patients with a prescription for metformin modified-release 500mg.

The notice allows metformin modified-release 500mg to be replaced with either immediate-release metformin 500mg or metformin modified-release 1000mg, depending on the prescribed dose.

The notice must be given effect under State or Territory law before pharmacists can supply according to the specified substitution.

The patient must consent to the substitution.

The pharmacist does not require prior approval from the prescribing doctor.

However, pharmacists should notify the prescriber of the substitution as soon as possible.

The notice applies from 13 May 2020 until 31 July 2020.

Information for pharmacists

Use your professional and clinical judgement to determine whether a patient is suitable for substitution under the Serious Shortage Medicine Substitution Notice and ensure the patient is fully informed and consents to the change.

Please refer patients to their doctor or diabetes nurse educator if substitution is not appropriate or where alternative treatments other than substitution may be more appropriate (eg, alternative strengths, fixed-dose combination products or therapeutic alternatives).

For patients who are switched:

  • Counsel patients to undertake more frequent blood glucose monitoring and to see their doctor if they have any concerns about their glycaemic control.
  • Be alert that the switch from modified- to immediate-release metformin may lead to an increase in gastrointestinal adverse events and ensure the patient is counselled appropriately.
  • Ensure that patients are aware that dosing intervals may be different and ensure that this is appropriate for the patient.
  • Provide a Consumer Medicine Information (CMI) leaflet to patients who receive a substitution and discuss possible adverse events.

The Serious Shortage Substitution Notice must be given effect under state or territory law before you can supply according to the specified substitution. States and territories may also apply specific conditions to the pharmacist substitution, such as recording and prescriber communication requirements.

For more information, visit:

Text by: Australian Government Department of Health Therapeutic Goods Administration


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