Quincy and I are just talking about 5ASA rectal meds - Canasa, Rowasa, Salofalk - all mean the same thing for these purposes. They are just different methods of delivering a topical dose of 5ASA. So all the stuff we were talking about applies to Canasa too.
My personal recommendation would be to slowly taper the Canasa down as you get better until it is at 2 or 3 a week and then leave it there. Or just leave it at a frequency that suits you. You can certainly use them for maintenance. When you are in remission, you (probably) shouldn't need one a day but play around as you taper down and find the right dose for you. If your Dr doesn't think this is a good idea, refer him/her to the studies I posted and let him/her know that you'd feel better using Canasa for maintenance. I don't think many Drs would really prevent their patients from having some extra 5ASA meds if the patient is keen.
I *love* rectal meds! They have made the world of difference to me.
Quincy - yep, I always take the 8 Salofalk tabs a day. My Dr and I used to try to taper that amount down, but for some reason, I don't do well on less than 4g of oral 5ASA a day. 4g doesn't cause me any troubles or side effects so we've given up and are just going to leave it at 4g daily. He said in my recent appointment that there is now some evidence that younger people need higher (oral) 5ASA doses to maintain remission.