Anyone know the science behind Zoladex?!

[Kittykat8989]

I’m worried about the effect Zoladex is having on me. I feel so depressed like a deep never will get out kind of depression. I have NEVER felt like this in my life. Can only put it down to the Zoladex, I’m not on any HRT x

[Minchoo]

It changes your hormone level. I cannot remember the exact but reducing your estrogen levels and creating a temporary menopause

[Kittykat8989 in reply to Minchoo]

Have you been on it? Did you have any side effects if so x

[Alicepirate]

It works on the pitutary gland in the brain to stop producing leutinizing hormone, which (in men) stimulates the testicles to release testosterone and (in women) stimulates the ovaries to release estrogen. That what I found but I was put on it after menopause so must do something else as well. But it made me really really loopy and down much worse than the already difficult menopause . Its hard to manage.

Do you know how much longer will you be on it for ?

[Kittykat8989 in reply to Alicepirate]

I had my last one last week. I’ve never felt like this before so I’m a bit concerned about how long this will last. So it’s a scientific fact it can “mess up” your thoughts then x

[Alicepirate in reply to Kittykat8989]

yep definitely our moods are really finely balanced by our hormones so having one blocked gotta change stuff. Try to really look after yourself and think of it as a chemical thing rather than a reality thing. Youve also had a major op couple of weeks ago and sure the GA messes our heads up a bit for a while to. I always get a bit of a high the day after like oh that wasnt too bad then horrendous low

Just really look after yourself I felt so fragile on the zoladex . Just keep thinking 'you are stronger than you think ' Its really really hard xxxxx

[Kittykat8989 in reply to Alicepirate]

When I’m tossing and turning at night I try and remind myself it’s just a chemical thing. Problem is I suffer from anxiety ANYWAY. I have all these irrational fears like what if I die from

Lack of sleep. I tell myself it will mess up my heart and I’ll need a transplant (you can see why I don’t sleep!) Although I’m irrational I’m not usually THAT irrational.

I’m trying to be kind to myself but finding it hard as I’m so frustrated. I’ve felt physically shit all year and now I’m combatting that the endometriosis has weaved it’s way into my thoughts now 🤬 x

[Alicepirate in reply to Kittykat8989]

Me too think it gives us double double stress cos we not sure whats our 'normal ' level anxiety and whats chemical its bloody hard

yep it is the drug though too definitely just keep on keeping on with all the annoying tricks we've learnt to keep us a little sane and keep on writing its hard but we will be ok

Weve both had anxiety and managed before this is just a bit much but we can manage

[Kittykat8989 in reply to Alicepirate]

I know, my sleep has never been compromised when my anxiety has been bad so I’m guessing the Zoladex is playing a part.

Thanks for chatting to me, I realise I’m

not going mad!!!! X

[NoEndoInSight]

Hello Kittykat8989, I'm so sorry that you are having such a difficult time at the moment. 


It sounds like you need to contact your GP and prescribing specialist about how you are feeling as soon as possible.

Zoladex is a "GnRH Analogue/Agonist". As Alicpirate says, this class of drugs works on your “Pituitary/Hypothalamus/Gonadal Axis” to stop your body producing the leutinizing hormone which usually triggers your body's production of oestrogen / progesterone and thereby your monthly cycle.

However, your body uses oestrogen and progesterone for many body processes, and among those processes is the regulation of mood. Both hormones, but particularly oestrogen, play a vital role in your brain’s serotonin & dopamine (happy hormone), and melatonin (sleep hormone) level regulation and uptake. Consequently Zoladex’ suppression of your oestrogen and progesterone levels can cause very significant mood changes (including sometimes severe depression and anxiety).

Because these adverse effects are primarily caused by the hypoestrogenic (oestrogen-deficient) state "GnRH Analogues/Agonists" like Zoladex induce, many specialists prescribe them along with complementary dose of "add-back" HRT. The HRT is supposed to "add-back" enough oestrogen (& often also progesterone) to ease some of Zoladex’s more unpleasant neurological side effects without reactivating the growth of your Endometriosis. But every women's body is unique and it can take a bit of experimentation to find the right "add-back" HRT dose, so if you are offered HRT it is always important to bear in mind that some women need just a low dose of HRT, while others find that their body requires a much higher dose of HRT "add-back”. Different women also find different brands and formulations of HRT work better for them than others. It is all a case of trial and error finding the HRT dose that is right for you. It is also worth bearing in mind that, for some women, “add-back” HRT is not able to fully overcome Zoladex’s impact on their mood, and therefore a decision may need to be made as to whether it might be best to cease treatment.

So you really do need to let your prescribing specialist and your GP know asap that your mood is dipping and you are feeling so very low. The quicker they can help you find a way to manage this Zoladex side effect the better.

As well as monitoring your treatment more closely from now on, and trying to help you to find the right "add-back" HRT dose for you etc., your prescribing specialist and GP should also be able to provide you with appropriate and effective emotional support while you are experiencing mood changes while undergoing treatment - perhaps some counselling from a therapist who is familiar with these kind of hormone treatments and their significant impact upon the brain’s ability to regulate mood.

If you feel that your prescribing specialist and GP (or any other medical professional involved in your care) is not fully up to date with Zoladex’ published safety advice and side effects information, then I recommend that you print out the manufacturer’s “Summary of Product Characteristics” (SmPC) guidance published on Medicines.org.uk both for you to have a read through yourself, but also to show to your prescribing specialist and GP. The SmPC provides far more details regarding Zoladex’s known impact on mood (i.e. depression/anxiety) than the basic Patient Information Leaflet, but you can find both documents here:

medicines.org.uk/emc/produc...

Medicines.org.uk is the official website where the manufacturers of all licensed UK publish their current drug safety information, so this is recognised as a reliable information source by the NHS and its practitioners.

Also, if you find you are still struggling to secure help in dealing with your treatment’s impact on your mood, it can be useful to know that Zoladex is manufactured by AstraZeneca UK. All of the big drug companies have pharmacologists whose job it is to advise prescribing specialists, GPs and other medical professionals about their products, the potential side effects of those products, and how best to manage those side effects. Although drug manufacturers are not allowed to give this information to patients themselves, if you are struggling to get your prescribing specialist or GP to take your concerns seriously, you can report your mood side effects directly to AstraZeneca via their “Yellow Flag” system, and they can then offer advice as to how you might be able to get your concerns taken more serious. Their contact details are:

AstraZeneca Medical Information Direct Line

0800 783 0033

Sorry that was such a very, very long reply, but I hope it's a helpful one, and I really hope you get some support and feel better soon. x X x

[Kittykat8989 in reply to NoEndoInSight]

Wow that’s a fantastic response thank you so so much and exactly what I needed to read!

I was on tibilone but was told to come off it as it lessens the effectiveness of the Zoladex.

I’m coming to the end of my last injection now so it’s just a case of if I can push through a bit longer. I’m going to see how it goes....

It’s reassuring to read the science behind the Zoladex. I knew i wasn’t “myself”.... I was only told the great things about the drug. I was never given any warning about the side effects x

[NoEndoInSight in reply to Kittykat8989]

I'm so glad it was helpful. Sometimes just the knowledge that it is not you but the drug making you feel so out of sorts is all you need to help you keep going. Hopefully you'll start to feel yourself again over the next as Zoladex works its way out of your system.

All the best, x X x