I have had multiple partial obstructions, and my doctor has ok'd me taking miralax when I'm constipated. She always has me start with half a dose to see if it'll help. If you're truly obstructed....1-you'll know it, because your symptoms will get much worse so fast, and 2-laxatives can be REALLY bad if you're completely obstructed, causing you to even perforate....that being said, miralax works in your body by telling it to not absorb water in your colon, so that things move through easier, so it's the safest route to start with.
If you do decide to take a laxative, start with a half dose, and see how that goes before you move to a whole dose. The last thing you want is your body trying to get rid of everything inside, when there's something in the middle of your intestines blocking things from moving forward.
As for the Pentasa, I don't understand how your dr would think it would help a stricture in 7 days. Even starting a stronger medicine like Humira, you can have obstructions when starting them. It didn't help my obstructions until about 3 months of being on the med. (I had an obstruction about 2 weeks after starting Humira, but haven't had one since it kicked in and started working!!!!!)
I hope you get some relief soon!
32 yr old female-dx with Crohn's in '97 after emergency resection and appendectomy, 2nd resection '05, Bilateral pulmonary emboli 10/09
Currently on Humira, Omeprazole, Effexor, Seroquel, Calcium, Vit D, Coumadin