Miralax could work for you, it depends on the dosage. It is an osmotic so it is not habit forming nor will it injure the colon.You can take it any time of day or night and try different dosages.Sometimes it works for me, like at night, I will take 2 heaping capfuls dissolved in 3 glasses of -currently, Powerade Zero. The key is to dissolve it in lots and lots of liquid.