Comparison of Lubiprostone and Placebo for the Relief of Constipation From Constipating Medications

Constipation from medications is a serious and common condition. Lubiprostone has properties that make it a candidate drug. One hundred volunteers with constipation who are taking medications known to cause constipation will be randomized to take lubiprostone or placebo for 28 days. Therapeutic outcome will be evaluated by investigator and study subject assessment.

Lubiprostone is a novel chloride channel activator that increases intestinal fluid secretion and motility. It is FDA approved and indicated for treatment of chronic idiopathic constipation and recently, constipation-predominant irritable bowel syndrome.

The Physicians Desk Reference lists over 90 Brand medications with reported incidence associated with constipation over 3%. Little data are available about treatment responses. A recent publication by our group reported treatment success for medication constipation using polyethylene glycol. Since ongoing studies are addressing the role of lubiprostone in opioid constipation, this work will be enrolling medication constipation study subjects not using opioids.

In this study, patients who meet diagnostic criteria for constipation will be randomized to receive 28 days of treatment with lubiprostone 24mcg twice a day. Data will be collected to evaluate therapeutic outcome.

Eligibility Criteria:
Inclusion Criteria:

* Adult male or female outpatient age 19 or older.
* Patients meet International Congress of Gastroenterology (ROME III) clinical criteria for constipation\*:

  1. Must include two or more of the following:

     1. Straining in \> 1/4 defecations;
     2. Lumpy or hard stools \> 1/4 defecations;
     3. Sensation of incomplete evacuation in 1/4 defecations;
     4. Sensation of anorectal obstruction/blockage in \> 1/4 defecations;
     5. \<3 defecations/week.
  2. Loose stools are rarely present without the use of laxatives.
  3. There are insufficient criteria for irritable bowel syndrome. \*Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.
* Use of one or more of listed medications known to cause constipation.
* If female and of childbearing potential, patient must be surgically sterilized or using oral contraceptives, depot contraceptives, intrauterine device, or testifies that she is monogamous with a vasectomized partner, or practices abstinence and will continue to do so during the duration of study. Mandatory compliance is required. Serum pregnancy tests will be performed at screening and during needed follow-up. Negative results will be received before inclusion and administration of first study dose. If pregnancy occurs during the trial, the investigator is notified immediately resulting in prompt discontinuation.
* Study subjects must not have received lubiprostone for more than 72 hours.
* Written informed consent.

Exclusion Criteria:

* Known or suspected obstruction, gastric retention, ileus, perforation, fecal impaction or inflammatory bowel disease.
* Severe diarrhea.
* Prior small bowel or colonic resection or colostomy.
* Weight \< 80 lbs.
* If the patient has constipation that according to the investigator's clinical judgment is not the result of constipating medications but is suffering from a secondary cause including but limited to factors that are dietary, neurologic, congenital, diabetic or hypothyroid.
* Positive stool hemoccult (Can be included if colonoscopic evaluation is subsequently negative).
* Significant cardiac, renal or hepatic insufficiency.
* Pregnant or expecting to become pregnant within 120 days of study enrollment.
* Lactating or breast feeding.
* Subjects using opioid medications.
* Subjects who in the opinion of the investigator would be unable to comply adequately with the study plan.
* Use of investigational drugs in the last 30 days.
* Patients with known allergy to lubiprostone.