Hi prof,
Sorry no one has responded. From what I've heard, and from Googling this med, you are not supposed to take it long term. It is for short term relief only, unless instructed by your doc. The website doesn't mention any cramping side effects. In fact, it says to NOT use the medication if you have abdominal cramps. Here is the website:
Colace
Hopefully you will discuss your symptoms and long term use of this med with your doc or pharmacist.
Take care.