Hiya
I had this for my labour and for me personally I didn't think it was that great - but my pain threshold is rubbish so others may have thought it wonderful. I was pretty out of it for my labour (pethadine, gas and air) but I remember the contractions very clearly and don't feel like they were less painful for taking this drug. I remember I had a thing to press and then it wouldn't let you press it again for about 5 minutes I think, so you didn't take too much.
My labour wasn't great though (28 hours!) and the epidural didn't work either - it kept falling out!! In the end I had a spinal block in theatre and it was the best feeling ever - no more pain LOL!
Sorry my story isn't positive in terms of pain relief but I did have a healthy baby boy
Good luck xx