Took miralax wednesday and thursday but its now tuesday and doesnt seem to be working. is it ok to take regular strength exlax?

The more important concern is to find out what is causing your constipation. Be sure to drink lots of liquids in order for the laxative to work effectively. Does your diet have enough fiber in it? Increasing your intake of fruits/vegetables may be helpful. If Miralax taken twice is not resulting in a bowel movement, it is likely time to get evaluated by your doctor so proper treatment can be done.