I have been having a look at the notes for this drug, and it is used in cases of fluid retention, as well as heart problems, and one of the side effects can be constipation, so I would chat with your vet about it and consider feeding a food that is easy to digest and passes through quickly, so there is no build up of food and therefore gas in the bowel. It means you will have to pick up sloppy poo, but should reduce the smell! Try her on one of the cheaper tinned foods, and maybe something oily like sardines once or twice a week to keep her system well oiled.