THE TGA has advised of shortages of warfarin medicines and, to ensure that access to the limited stock is maintained as widely as possible, it is urging pharmacists and consumers not to stockpile brands Coumadin or Marevan.
The supplier, Viatris, advised the TGA of shortages of several of its warfarin products due to manufacturing issues recently.
The shortages currently affect Coumadin (warfarin sodium) 2mg and 5mg tablets.
Warfarin is an anticoagulant used to prevent blood from excessive clotting or forming harmful clots for patients at risk of heart attack and stroke.
While the two brands of warfarin marketed in Australia (Coumadin and Marevan) are both available in various strengths, due to the narrow therapeutic index of warfarin and the lack of data on bioequivalence between Coumadin and Marevan, these products are not considered interchangeable, the TGA explained.
The shortage of Coumadin 5mg tablets is expected to continue until 31 Jul, while the shortage of Coumadin 2mg tablets is expected to continue until 20 Mar.
To minimise disruption to patients, Viatris is working to increase the supply of Coumadin 1mg and 2mg tablets to allow patients to maintain their prescribed dose using a combination of the lower strengths available, in consultation with a healthcare professional.
The TGA says it's working closely with Viatris and other stakeholders to minimise the shortage impact.
The TGA is seeking advice from relevant stakeholders on details to include in a proposed Serious Scarcity Substitution Instrument.
The instrument, if made, will allow pharmacists to dispense an alternative strength of the same warfarin brand if the prescribed strength is unavailable.
If substituting or switching is unavoidable, close monitoring with frequent International Normalised Ratio testing is recommended, the TGA stated.
The TGA is also aware of concerns raised about the new packaging of the warfarin product range (blue bottle presentation) and is working closely with Viatris to further differentiate the different strengths of each product label without disrupting supply.
Viatris holds limited emergency stock of Coumadin that can be shipped directly to pharmacies in urgent cases.
Pharmacists can call Viatris on 1800 314 527 to enquire about access to these medicines.
The above article was sent to subscribers in Pharmacy Daily's issue from 09 Mar 23
To see the full newsletter, see the embedded issue below or CLICK HERE to download Pharmacy Daily from 09 Mar 23
