It's not like you to worry!
Dr James le Fanu in the Daily Telegraph points out that taken long-term, this particularly medication can alter the acid in the gut so that the tablets no longer have good effect. There has to be acid in order to break down food, maybe read Michael Moseley's book, he describes transit really well.
However: like anything, taken under supervision and for a short-while to see if there is healing, should be beneficial for your digestive tract. Why not begin them on a Friday so that you can be near a 'loo at the weekend? You may find that your bowel action alters but not significantly. How much of that will be because you are worried that your bowels will loosen?
If I am on the Motorway and my bowel suddenly clenches, panic sets in
because a) I don't want to stop at a Service Station: I HATE them, why can't the loos be close to the car park! and b) I daren't move in case my bowel lets go B4 I get to the loo
. It's never happened. But!
Endoscopy is not something I would ever want to face
so well done! Also the Staff see more people than we do with these conditions so if you have discussed your worries, they should be able to reassure you.