Aggressive Bladder Cancer: Tips to help hold meds in bladder?

My husband is on his third Infusion treatment with gemcitibine . So far no real side effects or problems. The only thing he is having a rough time with is holding the drug in his bladder for the hour. We have to stay there as they have to leave cathedar in so meds stay in his bladder. Some people can get the infusion and leave but he cant hold it in so we stay.
It is uncomfortable in waves for him. It comes and goes.
We get through it as I sit with him and watch tv in his private little space @ the hospital.