Endometriosis UK
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Prostap Side Effects

Hi I am just wondering if you could share some of your Prostap side effects with me as I feel like I’m going in sane!! I feel depressed, my feelings about loved ones have changed, I am foggy and forgetful, the hot flushes are unbearable and I feel a total disconnect from my normal life. I have a lot to be happy about and I’m just not! I have recently been prescribed Tibolone (a form of HRT) and hoping this helps! I am supposed to have another injection soon but don’t think I can cope with feeling like this for much longer!

Thank you in advance lovely ladies😘

4 Replies

Hi flower,

I am on the Decapeptyl injections and just finishing month 4 on them.

It's the same thing you are o. I was also on Tibolone but had to stop it as my bleeding and pain came back within 3 days of taking it!!

I found the first month on the injections a bit tough as at first your body goes a bit mental and the pain gets worse. I was told its because your hormones get more at first.

But that's normal and after 4 weeks it settles down and gets much better! So if you only just got the injections don't worry it should get better.

And maybe leave the tibolone away at first just to see how you feel. (But ask your doctor if you are concerned about leaving them away)

I was told to leave the hrt away but my Endometriosis is quite bad.

And I actually don't mind the hot flushes as I am always so cold :)

That's the only side effect I have.

So the first 3-4 weeks were a bit rough and now I feel brilliant :)

Maybe I am lucky though.

Hope you feel better soon :) xx


Hello Flower11,

I'm so sorry you are having such an awful time. You are definitely not going insane, all of the symptoms you list are know side effects of Prostap treatment. Sorry that this is going to be such a long reply, but hopefully it will be of help.

Prostap is a "GnRH analogue/agonist" and it works by suppressing your body's oestrogen / progesterone levels and your monthly cycle. When you first start treatment you can also get a "flare" of symptoms (heavy bleeding & pain etc.). Many women find that the worst of their side effects settle after the first 4-6 weeks.

However, you definitely should let your Specialist and your GP know asap about the side effects you are experiencing and their severity, particularly the mood changes and memory problems. They should be monitored for the duration of your treatment, especially if any of them appear to be getting worse over time rather than better.

Many of the side effects you are experiencing: brain fog (memory problems/poor concentration), and mood changes (including depression and anxiety) and others severe joint pain and dysfunctional bleeding are caused by hypoestrogenism (oestrogen-deficiency). Although Prostap is prescribed specifically to suppress oestrogen levels (and thereby suppress your endometriosis), your body does use oestrogen for other very necessary purposes. This is why so many specialists prescribe Prostap along with a very low dose of "add-back" HRT like Tibolone. Tibolone should add-back enough oestrogen to suppress your Endometriosis, but not suffer too many / any severe symptoms of hypoestrogenism (oestrogen-deficiency). However, the "add-back" HRT dose is not a "one size fits all" thing - different women find they need different doses, so it is important to keep your Specialist and GP informed of any symptoms you develop while on Prostap so they can adjust the "add-back" HRT dose if necessary. There are also different brands and types of HRT and some suit different women better. For example, my body struggles with synthetic Progesterone, so I found bio-identical HRT worked much better for me.

Your Specialist and GP's responsibility does not end at prescribing and administering Prostap, they should also be helping to provide you with appropriate and effective medical and emotional support to cope with Prostap's side effects for however long or short the amount of time you are being prescribed it. They should also be assessing (on an ongoing basis) whether your Prostap / "add-back" HRT dose is working for you or whether it needs adjusting.

Prostap is manufactured by a company by Takeda Pharmaceuticals International. You can download their published guidance regarding Prostap's actions and side effects here:


The SmPC (Summary of Product Characteristics provide more detailed information than the basic Patient Information Leaflet.

I have found that it can sometime help to print this SmPC guidance off and to take it with you when you discuss Prostap treatment and the new symptoms you've developed while on it your Specialist and GP, as referring directly to the manufacturer's guidance and list of known treatment side effects can help keep the conversation focused.

Many apologies once again that that was a bit of a long reply, but I wanted to give you as much information as I could. Sometimes it can just help to know that the symptoms you are experiencing are just drug side effects and can be managed and treated with the appropriate help and support.

I really hope that things pick up and that you start to feel more like yourself again soon, x X x


I think when I was on decepeptyl with tibolone for a few months.... If I remember correctly it made me feel completely insane too. I particularly remember feeling very tearful and extremely paranoid. It really effected by behavior as well as making me feel horrendous. I would just start feeling normal and it was time for the next one. I went on to ovaries removed, and then due to progesterone intolerance I had a hysterectomy. Joy! You are definitely not going mad. It's the treatment x


My first round of prostap I was good had hot flushes but nothing major then I had ivf had my daughter now about to start another round of prostap hoping it was like before but the specialist said if I had bad side effect the doctor could prescribe some pills to counter act the prostap you should ask your doctor xxx


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