Why has there been an ongoing HRT patch shortage in Australia?

The shortage of transdermal estradiol patches reflects global manufacturing and supply chain pressures on the products made by Sandoz (Estradot) and Juno Pharmaceuticals (Estraderm MX 100). These are not the result of changes to prescribing rules or PBS access — they are supply-side manufacturing and distribution constraints. The TGA has been managing the shortage since at least 2024 through the Serious Scarcity Substitution Instrument and approvals of overseas alternatives under Section 19A of the Therapeutic Goods Act.

Is it safe to switch to a different brand or strength of estradiol patch?

Different brands of transdermal estradiol patches use different delivery mechanisms and patch sizes, which can mean the same labelled dose delivers slightly different amounts of hormone. Switching between brands is generally manageable, but any change in symptom control — hot flushes returning, sleep disrupted, mood shifted — after a brand switch is worth bringing back to your GP. The substitution instrument does not mean all switches are clinically equivalent at the individual level; it means pharmacists have authority to dispense a named alternative when your prescribed brand is unavailable. If you have cardiovascular risk factors or a history of venous thromboembolism, the route-of-administration question is particularly worth discussing with your GP before switching to an oral preparation.

Australia's HRT patch shortage: what the SSSI extension means for you

What just happened

Australia’s shortage of transdermal estradiol patches — specifically all strengths of Estradot (25, 50, 75, 100 micrograms) and Estraderm MX 100 — continues through 2026 with no resolution expected before year’s end. The TGA has extended the Serious Scarcity Substitution Instrument (SSSI) to 28 February 2027, confirming the mechanism that allows pharmacists to dispense alternatives without a new prescription will be in place for at least another eight months.

The extension of the SSSI to February 2027 is not good news. It signals that the supply problem is structural and slow-moving. But the instrument itself carries important practical information for the thousands of women who have arrived at a pharmacy, been told their regular patch is out of stock, and not known what to do next.

The person reading this may have been managing this shortage for months. She knows the frustration of a pharmacy telling her the product is unavailable, the uncertainty about whether switching brands is safe, and whether her symptoms will change. This piece is about the practical landscape as it stands at mid-2026.

The both-and

The shortage is real and affects a medication that matters significantly for quality of life in perimenopause and menopause. The available alternatives are workable for most women — with some caveats worth knowing.

What the SSSI actually allows

A Serious Scarcity Substitution Instrument is a formal TGA mechanism that allows pharmacists to substitute a specified medicine with a named alternative — in this case, different brands or strengths of transdermal estradiol — without requiring a new prescription from your GP. The current instrument covers all Estradot strengths and Estraderm MX 100.

The practical effect: if your patch is unavailable, your pharmacist can dispense an approved alternative under the same prescription. You do not need to return to your GP solely to update the script to a different brand. This removed one of the main barriers the shortage created — the cost and wait time of a new prescription every time a brand was substituted.

This is underutilised because many women do not know the SSSI gives pharmacists this authority. If your pharmacist has been sending you back to your GP for a new script each time, ask specifically about the SSSI for transdermal estradiol.

What alternatives exist

The TGA has approved overseas-registered alternatives under Section 19A of the Therapeutic Goods Act — products not normally available on the Australian market that have been permitted specifically to manage the shortage. They are manufactured to comparable standards but may look and behave differently from the Australian-registered versions: different patch size, different adhesive, different wear experience.

The Menopause Society of Australia maintains a current list of available alternatives and substitution guidance. This is the most practical real-time resource, because the in-stock situation changes and varies by pharmacy and state.

Estrogel (estradiol gel) and oral estradiol are available for women whose prescription or clinical situation allows for a route-of-administration change. That is not the same decision as a brand substitution within the transdermal route — it warrants a conversation with your GP.

The clinical relevance of the route-of-administration question

Transdermal estradiol has specific clinical advantages over oral estradiol in certain populations — particularly regarding VTE (venous thromboembolism) risk. Oral estradiol undergoes hepatic first-pass metabolism, which is associated with increased clotting factor activity and therefore elevated VTE risk relative to transdermal delivery. For women with migraine with aura, a personal or close family history of VTE, or established cardiovascular disease, the transdermal route is the preferred choice on clinical grounds.

For these women, a route-of-administration switch from transdermal to oral is not a neutral substitution. The shortage does not change their clinical situation — they still need transdermal delivery — and the SSSI covers transdermal alternatives specifically so they do not need to switch routes.

For most women without these risk factors, oral or gel preparations are reasonable alternatives if transdermal supply remains consistently difficult. The question is worth asking explicitly: “Given my history, what’s the safest alternative route if I genuinely cannot get my patch?“

2 cents

Two practical steps if you are currently managing this shortage:

First, check the Menopause Society of Australia’s shortage page before calling your GP. It shows what is actually available and the current SSSI terms. Your pharmacist can substitute within the instrument without a new script — you do not need a GP appointment to change brands.

Second: if you have switched brands and your symptom control has changed — hot flushes returning, sleep disrupted, mood shifted — that is worth bringing back to your GP. Different patch formulations deliver slightly different bioavailability in some individuals. A change in symptom pattern after a brand switch is a legitimate clinical signal.

This is general health information and does not constitute individual clinical advice.

Verdict

Verdict: yes — worth knowing about.

The HRT patch shortage continues with no near-term resolution, the SSSI has been extended to February 2027, and the practical substitution options are underutilised because many women do not know the instrument removes the need for a new prescription. For the thousands of Australian women managing menopause or perimenopause on transdermal estradiol, this is information with direct, immediate relevance.