Share article

Print article

The drug goserelin - commonly known as Zoladex - has been a quietly crucial medicine in Australia for decades.

This prescription medicine is used to suppress sex hormones, and is a key medication for the treatment of prostate cancer, endometriosis and some breast cancers.

However, the international pharmaceutical company AstraZeneca has announced it will remove low-dose Zoladex from Australia's Pharmaceutical Benefits Scheme (PBS) and pharmacy shelves from November. This has many patients and clinicians worried this will impact patients' treatment and overall health.

So what is this drug, and why is it being pulled from the Australian market?

And if you currently take it, should you be worried?

Zoladex is a synthetic hormone that affects how the pituitary gland functions. Specifically, it works to stop the production of testosterone in men, and oestrogen in women.

Given it helps reduce hormone levels, Zoladex is an effective way to treat medical conditions that are caused, or exacerbated, by sex hormones.

This includes prostate cancers, which account for 30% of all cancer diagnoses among Australian men. Prostate cancers need testosterone to grow, so reducing testosterone levels in men is one way to stop cancerous tumours from developing. This type of treatment is known as androgen deprivation therapy.

Zoladex can also be used to treat conditions that affect women. Certain breast cancers - known as ER+ cancers - require oestrogen to grow. So by limiting production of this hormone, Zoladex can help slow the growth of these cancers, particularly in pre-menopausal women. Oestrogen also contributes to pain and inflammation in women who have endometriosis, so reducing oestrogen levels can help patients manage these symptoms.

Two Zoladex medications are currently listed on the Australian Register of Therapeutic Goods. This includes a low-dose form (3.6 milligram) and a high-dose form (10.8mg). Both contain identical ingredients and are administered through a small implant injected under the skin.

While the low-dose product needs to be administered once a month, the higher-dose formulation only needs to be delivered once every three months.

AstraZeneca - the company that produces Zoladex - has decided to pull its low-dose medication from the Australian market for "commercial reasons".

The company has stated these are unrelated to the drug's safety or efficacy, but has not explained what the exact reasons are.

However, one possible factor could be a difference in demand for low-dose Zoladex in Australia versus overseas. In 2025, there were nearly 100,000 scripts for the medication across the country. But for a company such as AstraZeneca, it may be more profitable to go from producing two products to one, particularly in the Australian market which makes up just 2.1% of the total global demand for medicines.

However, other factors may also have contributed to AstraZeneca's latest decision. It may be looking to cut costs, or free up manufacturing capacity to start producing a new medicine or increase supply of an existing medicine.

AstraZeneca will not remove low-dose Zoladex from the Australian market until November 1 2026. It says this is to give clinicians and their patients enough time to transition to new medicines or make other treatment arrangements.

However, Australians will still be able to access the higher-dose form of Zoladex. For some patients, it may be suitable to switch to this form of the drug. To make this a more affordable option for patients, AstraZeneca is reportedly applying for high-dose Zoladex to be listed on the PBS.

Regarding cancer treatment, doctors are not limited to one specific drug. So if higher-dose Zoladex is not suitable, an oncologist could recommend a patient use a different drug or combination of medicines.

For women with breast cancer, they have access to more than 90 different chemotherapy treatment plans. Only three of those 90 plans require Zoladex. However, only some of these plans can be used to treat ER+ breast cancers. Similarly, more than 20 different medicine combinations can be used to treat prostate cancer, and only one of these includes Zoladex. So a doctor may be able to select an alternative treatment that still meets their patient's specific needs.

And for women with endometriosis, alternative hormone treatments - for instance contraceptives and progestogen tablets - may be a suitable replacement for Zoladex.

But if you currently take Zoladex and are worried about losing access to the low-dose form, speak to your doctor or local pharmacist.