Lubiprostone
DrugColonic transit study performed and stool/symptom diaries will be reviewed. Eligible subjects will be given a lactulose breath test and randomized to Lubiprostone or placebo. Treatment group receives 24 mcg Lubiprostone twice daily and placebo group receives pills (identical in appearance to the study drug) for one month. Subjects will be asked to maintain a daily stool/symptom diary for duration of the study. In the middle of the study a research coordinator will call the subjects to take questions/concerns and record adverse events. Lactulose breath test will be repeated, constipation questionnaire filled out, colon transit study performed.