The investigators will recruit a total of 136 diabetic men and women with constipation into this study from both The Emory Clinic and The Atlanta Veteran's Administration Hospital. The investigators will track spontaneous bowel movements defined as a bowel movement in 24 hours after initiation of study drug (SBMs) in all patients two weeks before treatment with lubiprostone as well as measure baseline colonic transit using the Smartpill pH capsule. Colon transit reflects that rate of colonic peristalsis and movement of stool through the large bowel.

Patients will receive either lubiprostone 24 micrograms (mcg) orally twice a day for 8 weeks or placebo. Primary and secondary endpoints will be the number of SBMs/week and colonic transit time as measured by the Smartpill capsule, respectively. The number of SBMs/week will be evaluated at 0, 2, 4 and 8 weeks after initiation of therapy. The investigators will over-sample African American patients to achieve approximately 50% enrollment of this group. In a subanalysis, the investigators will assess response to treatment between the general population and African Americans.

We hypothesize that lubiprostone will significantly increase the number of SBMs as well as decrease colonic transit time and improve quality of life in constipated diabetic patients compared with placebo.

Diabetes mellitus (DM) is very common in the United States, and the incidence as well as prevalence of this disease are increasing. DM is not only a risk factor for cardiovascular and pulmonary conditions, but is also linked with several digestive complications. Among digestive complaints, constipation occurs in approximated two-thirds of patients with DM, making constipation the most common gastrointestinal (GI) complaint among type 2 diabetics. Consequently, these patients suffer abdominal pain, bloating, and have a lower health related quality of life when compared with patients without DM and GI symptoms.Constipated individuals may be reluctant to eat on a regular schedule which may worsen glycemic control as well as the symptoms related to an underlying diabetic enteropathy.

Effective therapies for constipation are limited and there is little data evaluating the treatment of constipation, specifically in diabetic patients. Lubiprostone has been shown to be superior to placebo in increasing the number of spontaneous bowel movements (SBMs) in patients with chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). However, lubiprostone has not been previously studied in diabetics suffering with constipation. Furthermore, other prokinetic pharmacotherapeutics targeted toward constipated patients with diabetes mellitus type 2 are lacking.

African Americans have the highest rate of DM compared with other ethnic groups in the Unites States. Furthermore, constipation is more prevalent in African Americans compared with other minority groups. However, there is little data evaluating the prevalence of constipation and the response to treatment in African Americans. Therefore, more information regarding the severity of symptoms, differences in bowel patterns, colonic transit, and response to therapy is important to improving the management of constipation in this group. Hence, in a subanalysis, we will study whether the responsiveness of African American patients to lubiprostone differs from that of the general population.

Given the dearth of information on the effectiveness of lubiprostone in diabetics, who have a particularly strong need for alternative safe and effective treatments for constipation, we propose to assess the effectiveness of lubiprostone in constipated diabetic men and women.

This is a randomized double- blind placebo controlled trial of lubiprostone in the treatment of constipation in diabetic patients.

Inclusion Criteria:

• Diabetic patients with constipation.
• Patient must be on stable oral or subcutaneous hypoglycemic medication for 6 months.

Exclusion Criteria:

• Acute infections
• Ischemic bowel syndrome
• Gastrointestinal obstruction