I took Zelnorm pre-diagnosis. Before I would ever recommend it, or another med to someone is if they have tried all the other alternatives unsuccessfully: fiber therapy (natural fiber), changed diet, natural supplements, good physical exam. I believe there are a lot of folks on it that could find other solutions, but unfortunately doctors don't push those natural solutions... Relying on the meds can end up making things worse over time.
That being said ! I found that Zelnorm helped somewhat with my constipation--not at all like the gluten-free diet or psyllium has though. It created more of a sporatic D in me...which even that was a relief at the time. My other thing with laxatives and gut-activating meds is that they don't necessarily produce a good BM--one that moves all the stool through the system--but instead a watery mess that gets out some BM, not all perhaps. I know, I've thought long and hard about this

If someone has constipation, I definitely recommend trying natural pysllium--it works better for me than any med, supplement or laxative ever did, and it is not harmful. It picks up stool that has been sitting in the gut for a while and flushes it out.
BUT-to get back to your question again friend (excuse my tangent!), if other alternatives have been tried, then I think Zelnorm is a better option than chronic constipation. I didn't have any weight gain, maybe some gas/cramping...especially at time of BM, but don't remember anything serious in the way though.
PS--You do about need a degree to read those labels! Did you talk to a customer service rep only? They should refer you to the 'lab' department or send the inquiry in on their own...that's my typical experience anywho. I get different answers depending what number I call. There are others here who take Zelnorm--perhaps they have called in to ck on the status?
PS--on another topic! did you go to your class reunion? I have mine this year and am trying to decide whether to go..
Carrie--like the new pic-cute!