What Causes Leg Cramping After Changing Dose Of Lactulose And Miralax?

Hi , My daughter is 4 and has been taking Lactulose and Miralax twice a day for the last year and a half - she was diagnosed as having issues with nerve problems in her lower intestine . My question is , her dose was recently changed and now she is experiencing daily leg cramps - could this be connected ? thank you for your help , Elizabeth