bejart,
oh the joys of opiods! The longer you are on them, the worse things get in the GI department.

razzle51 has brought up one of the most effective things. Miralax. You can get it in the US in OTC generic as well. Don't use too much of it though as it can make your bowels too soft. Overall though, it doesn't seem to cause cramps, at least it doesn't in me.

OTC ducostate sodium works well if you are having a real problem with constipation. Make sure it won't react with any medications you have though. The down side is that it can cause some cramps. After two weeks of ilius though, your GI is so full of gas etc. that the discomfort of the cramps is less painful than the constipation.

If you are on opiods or narcotics, and can stay ahead of the constipation, that is best. Dealing with it after you have been suffering for days is less effective.

The first line of defense is eating a fiber rich diet. If you are not a vegetable and fruit eater, start out slow or the fiber itself can give you gas. Natural is always best.

I hope you can avoid a serious bout of constipation.

Sam