Magnesium Citrate works great! If it's really bad, start with 2000 mg and give it a day. It's it works too well, cut it back to 1500 mg and so on.
If you're miserable and you NEED to get cleaned out, try Milk of Magnesia. Take the max dose and drink 10 oz of water before - not right before but within the hour. Then, after taking it drink another glass of water. MoM holds water in the gut and is NOT a stimulant. It works well - should work overnight. If you're worried about it 'working' while you're AT work, try taking it around 4 or 5 in the afternoon.
If you start to rely on stimulant laxatives, it will make matters worse and you may become dependent on them.
I am on pain meds and IP - NOT a good combo! The magnesium works great. Well, that and a cup of coffee!