[souffle]

I'm so sorry to hear Poppy is ill. Most people would have passed her by at 2 years of age so you did great to take her on. This really is a good age for a hamster to be honest and it may be that things inside her are just not as they should be anymore. Her immune system will also be weaker making it hard for her to fight off problems.
I would say it takes 3 days for the meds to kick in and if you don't get any improvement at that point it may be that she is not responding or there is another cause at the root of the problem which the meds cannot cure or the bowel has been damaged beyond repair.
Females can get womb infections which are very serious and can also cause the diahorroea. She may have a tumour higher up in the tummy or reproductive tract. Is her tummy swollen or bloated at all? Has she lost weight or drinking a lot?
For now keep her warm and hydrated and also feed a little teaspoon of live yogurt to see if that will help her tummy.
I am glad she has you to care for her and if it comes to making a decision then you know her best and will know in your heart the right ay forward.
Welcome to Hamster Central x