Hi there,
Just noticed this thread (sorry for the delay in replying). My Gastro changed my Asacol to Mesavent XL back in May. I was also put on a daily dose of 4.8g, but couldn't tolerate them at all. Managed a week and then they were stopped. Mesavent is also another form of Mesalazine. It's a newer tablet and is a slow release form of the drug that targets the whole colon (from what my Gastro advised). I had no problems at all with Asacol, having taken it for over 10 years, but for some reason, this tablet made my joints swell, and gave me flu like symptoms.
Hope that they are working well for you,
Andrea