Ask a Pharmacist: Zoladex
By Prue Luck
It can be a challenge sorting fact from fiction, and horror stories from side effects when it comes to finding information on some of the medications and treatments suggested for those affected by endometriosis, adenomyosis, PCOS or infertility. Zoladex is one of the most talked about topics in the endometriosis community, so in this blog we asked pharmacist Prue Luck to give us “just the facts, m’am” about how it works, so that we can all be informed and empowered to make the decision that’s right for us, armed with the facts we deserve.
Zoladex is a commonly used product in the treatment of endometriosis symptoms, however when “googled” it is better known for its role in prostate cancer. This blog will address how and why it is used in Endometriosis.
Zoladex (brand name) is an injectable implant which contains the drug “Goserelin”. Goserelin belongs to the family of medicines called “Gonadotrophin-releasing hormone agonists” or GnRH agonist for short. This family of medicines is used in a variety of medical scenarios including Infertility, Endometriosis, Uterine Fibroids, Breast cancer and Prostate cancer. When reading how the medicine works, it can be very hard to understand, but this is how I like to explain it for my patients in the pharmacy:
When commencing a GnRH agonist (eg. Zoladex), it stimulates a large release of follicle stimulating hormone (FSH) and luteinising hormone (LH) (these are the “gonadotropin hormones” hence the name GnRH). These are hormones released during the ovulatory phase of your menstrual cycle. FSH is produced by the pituitary gland and tells your ovaries to produce follicles, which contain an egg. The maturing follicle causes a surge in oestrogen, which in turn stimulates the uterine lining to thicken, oestrogen continues to rise and triggers LH, followed by ovulation.
This is where the drug can be used for infertility (switches those hormones on HIGH). However when continued for prolonged time periods, it suppresses your gonadotropin release. The reason for this is because all your hormone accepting receptors in the body are so “full” now from all of the hormones dished out when starting the drug, that now they can’t take anymore so your body will stop releasing them (sleepy kind of like a food coma). Hormones won’t have an effect if they cannot find a target cell to act on, therefore if all the receptors are full, any hormone released won’t actually have an action - your body knows this, and saves itself the trouble. It enjoys it’s food coma. That’s where the role of Zoladex in conditions like endometriosis comes in.
We know that hormones, like oestrogen, can be potential fuel for endometriosis. Without the food source of hormones, this is how we help slow down hormone based cancers like breast or prostate, and suppress many of the symptoms of endometriosis. This is why you may see Zoladex being used in the treatment of endometriosis, because suppression of these hormones can help in reducing the pain symptoms.. This is why Zoladex has a shared role in both genders.
As you can imagine, whenever we play around with hormones, we introduce side effects. Unfortunately, they are hard to avoid. You may have heard the words “inducing menopause” when talking about Zoladex. This is because of how the drug has put your hormone production to sleep, similarly in menopause when your hormone production is waning. The side effects of Zoladex are not few or far between from those shared with women in menopause. The effect on hormone production means that your FSH and LH won’t perform their usual role in the menstrual cycle, and will temporarily suppress your cycle.
In the first 2 weeks, when you get the hormone high, you may experience a flare up, however hopefully there should be a reduction after this initial surge. Post initiation of treatment some commonly seen side effects are headaches, bleeding (usually light), hot flushes/sweats, reduced libido, vaginal dryness, breast tenderness or change in size, and/or joint pain. This is all in result of reducing the hormones within the body. They tend to sound very daunting but these are temporary, and not everyone will get every side effect - it’s an individual response. When GnRH agonists are used in endometriosis, they are not used longer than 6 months at one time. This is because our body needs these hormones back eventually, otherwise our body gets starved of their positive effects. When treatment is stopped and hormone production kicks off again, the side effects will lessen and return to how they were before treatment.
I know the feeling of sitting in the doctor’s room being told this is the treatment for you and how scary it can sound. I have sat in that chair myself. Questions never seem to arise until after you leave the doctor’s office and then panic sets in and you go to google or facebook groups for answers. I’ve done that myself too. The biggest advice I can give to all women when in this situation is DO NOT JUST GOOGLE !! Or at the very least, find a reliable source. How?
The correct information can always be safely found at your local pharmacy and costs you absolutely nothing. All you have to do is take the name of the product you want info about to the pharmacy and ask for the pharmacist to print you the drug information. This is your SAFE google search !! While you are there, you can always chat to the pharmacist too. People often forget that we are the drug experts. We spend 5 years studying the drugs that all doctors prescribe. We know a lot and love helping to share it! When you are educated on your proposed treatment/drug, you are then able to make a fully educated decision about your treatment.
I recommend avoiding facebook groups other than reliable, patient-centred groups like QENDO - many are not moderated and a lot of misguided information is found there. There’s nothing wrong with seeking support, that’s why we’re here! But remember that someone on the internet who is not a medical professional can only share their experience, and that is not fact, and can be vastly different to yours. Listen to these experiences, but then find reliable information to ultimately make the decision for your body. Women tend to write all the negatives about their experiences and very little positives, which can be overwhelming and daunting, At the end of the day we can never have our cake and eat it too - yes, side effects are not ideal but neither is endometriosis. For some, Zoladex is a much needed break from some debilitating symptoms. Others find their personal side effect profile intolerable, and that’s okay too. I can positively say my personal GnRH agonist treatments were sprinkled with all the side effects, however I had 6 months of little to no endo belly/flares, so I was happy. Endometriosis treatment is what I like to call a “balancing act”, and it’s about finding the balance that’s right for YOU.
It is important to note that Zoladex will not treat the disease itself, it will not cure endometriosis, nor will it treat the disease. Zoladex is one of many treatments that may be prescribed to treat SYMPTOMS, such as pain and heavy bleeding. It is not a replacement for quality excision surgery, which is the gold standard for the treatment of endometriosis, and should not be used to suppress symptoms before a formal diagnosis is made. Like the pill, this can mask important clues your body is sharing, while the disease continues unchecked if your symptoms are controlled. This blog is here to give you the factual information you need to make the right decision for you in partnership with your healthcare team.
Prue Luck – Pharmacist and Central QLD QENDO Coordinator
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