Prostap injection.

Hi Jewelse2b714 sorry to hear that your dad has been diagnosed with PCa. Thanks for the info about diagnosis, are you able to tell us if any other treatment has been prescribed or is the Prostrap the first medication?  I have been on Zoladex for 8 years (which is similar but slightly different) so can’t speak with knowledge, but I would doubt that the HT would have such an instant noticeable impact in 36-48 hours.  Is his jab monthly, quarterly or 6 monthly?  Personally, any noticeable changes following treatment I usually contact my team for advice/reassurance.  

I don't think it works that quickly ! The side effects are not from the drug they are from having lower testosterone levels. As testosterone does not decline immediately (takes weeks or months) the side effects work on a similar timescale.

There may be a physiological effect of relief from having the first injection over with which may make the patient feel tired. I found this with some of my treatments particularly the biopsy which made me feel very tired and emotional afterwards.

Rob 

Hi Jewelse2b714 I'm so sorry to hear of your dad's diagnosis.

I can only offer you both details of my own experience of receiving hormone therapy (HT) Prostap injections. I received a 4 week version of the drug on the 27th September 2023 at which point I was a couple of months before my 75th birthday. I was told that I had received the 4 week version to see if my body managed it without problems. If I had no adverse reaction I would receive 12 week versions after that first injection. That first injection had been preceded two weeks before by one of  Bicalutamide which I believe reduces a testosterone surge when the Prostap is introduced to the body.

That first injection resulted in absolutely no reaction initially although the well known and published side effects started to become apparent after a couple of weeks starting with hot sweats followed after a few months increasing erectile dysfunction (ED). May I suggest that your dad asks about treatment to help with the ED very early in his treatment, my hospital didn't offer this until I asked almost twenty months after the start of my HT. 

I consider myself lucky in that I have passed through radiotherapy treatment and come out beyond with only the above side effects persisting somewhat longer than many patients do but as of now, November 2025 these seem to be diminishing. 

If your dad continues to feel under the weather I suggest that you contact his treatment team.

May I wish you both all the very best in your journey through PC treatment. 

Rod

I had 2 x 3 monthly Prostap injections. I had all the normal side effects (reduced libido, hot sweats, insomnia) but they were all slow to take effect.

I wonder if there are any other things that might cause him to feel wiped out.

After my diagnosis, and when I began my treatment, I was so relieved that treatment had begun that I just a day or so of feeling quite tired.

It wasn't anything to do with the hormone therapy, just the way I was feeling.

I was also on bicalutamide for 2 weeks before the first injection. I can't say that the HT had anything to do with my tired state, but I can't say it didn't, either.

It seems to me that I had been told I would feel fatigued, so when I started, I was.