I used it from October 2008 to February 2009 - not exactly long term but I did get some side effects.

I was on a low dosage of one tablet per day (which I think is 500mg). I took mine at night before bed and after dinner as taking it whilst I was eating or just before food made me ill and so night was the best time for me. I think taking it at the same time every day also helped.

My bowels were very loose in the first few weeks of taking it - I think I first noticed the change in bowel movements on day 3. But they didn't last forever and once my body got used to the dosage it was ok.

I did at times dread to think what would have happened if I had been required to up the dosage... those first few weeks of knowing the location of any close toilet were not exactly fun.

Hope that has been some help to you.