Effects of Lubiprostone on Gastrointestinal Transit & pH in Irritable Bowel Syndrome (IBS) With Constipation

Inclusion Criteria:

• Males or females >18 years of age

• Meet Rome III criteria for IBS[2]:

• Recurrent abdominal pain or discomfort at least 3 days per month in the last 3months associated with 2 or more of the following:

1. Improvement with defecation

2. Onset associated with a change in frequency

3. Onset associated with a change in form (appearance) of stool

• *Criteria fulfilled for the last 3 months with symptom onset at least 6 monthsprior to diagnosis

• Fulfill the Rome III stool consistency criteria for IBS-C[2]

• Hard or lumpy stools for >25% of bowel movements

• Loose (mushy) or watery stools for <25% of bowel movements

• Capable of independently completing all requirements of the study including returningfor required visits

• Able to provide written informed consent for study participation

• Willing to discontinue prohibited medications during study participation

• Documentation of a normal colonoscopy within last 5 years if over age 50 years (orsigmoidoscopy if less than age 50)

• Documentation of normal thyroid stimulating hormone(TSH) level, complet blood count (CBC) and electrolyte panel within prior 3 years

• Females of childbearing potential must have a negative urine or serum pregnancy testat screening

• Females of childbearing potential must use an effective means of contraception duringthe course of the study

• Hormonal (oral, injectable, implantable, cervical/vaginal rings or patches)

• Double-barrier (condoms and/or diaphragm with spermicides) or intrauterinedevices provided under the care of a health care professional

• Abstinence, in this case documentation of counseling will be recorded

Exclusion Criteria:

• Unable to understand or provide written informed consent

• Pregnant or nursing

• Patients with IBS-D, IBS-M or unsubtyped IBS by Rome III criteria[2]

• IBS with diarrhea (IBS-D)

1. Loose (mushy) or watery stools for >25% of bowel movements

2. Hard or lumpy stools for <25% of bowel movements

• Mixed IBS (IBS-M)

1. Hard or lumpy stools >25% of bowel movements

2. Loose (mushy) or watery stools for >25% of bowel movements

• Unsubtyped IBS

1. Insufficient abnormality of stool pattern to meet criteria for IBS-C, IBS-D orIBS-M

• Documented allergy or intolerance to lubiprostone

• Failure of balloon expulsion test

• Inability to expel 50cc balloon within 1 minute

• Use of drugs known to affect gastrointestinal motility

1. Laxatives (stable doses of fiber taken for minimum of 4 weeks will be allowed) Osmotic laxatives: Magnesium hydroxide, Polyethylene glycol,Lactulose, Sorbitol Stimulant laxatives: Bisacodyl, Anthraquinones (senna), Misoprostol

2. Prokinetic agents: Metoclopramide, domperidone, erythromycin

3. Anti-diarrheal agents: Loperamide, Diphenoxylate, Bismuth

4. Anti-spasmotics: Dicyclomine, Hyoscyamine

5. Opioid, narcotic, opioid/narcotic-containing analgesics: Morphine, Hydrocodone, Codeine, Methadone, Propoxyphene

6. Probiotics

7. Systemic antibiotics within last 3 months

8. Recently initiated antidepressants (stable dose for >2 months for non-GIconditions will be allowed)

9. Benzodiazepines * Subjects taking prohibited medications will be required to stopthese at the screening visit and remain off of them until completion of thestudy.

• Initiation of dietary changes potentially altering bowel transit within 4 weeks

• Comorbid medical problems that may affect gastrointestinal transit or motility

1. Previous surgery involving the stomach, small bowel or colon (prior appendectomy,cholecystectomy, polypectomy allowed)

2. Previous history of small bowel obstruction for any reason

3. History of any gastrointestinal malignancy

4. History of dyssynergic defecation

5. Unexplained nausea and vomiting

6. History of inflammatory bowel disease (Crohn's or ulcerative colitis)

7. History of microscopic colitis (lymphocytic or collagenous colitis)

8. History of Hirschsprung's disease

9. Severe or complicated diverticular disease

10. Chronic pancreatitis

11. History of celiac disease

12. History of eating disorders (anorexia nervosa or bulimia)

13. Cirrhosis

14. Chronic hepatitis B or C infection

15. HIV infection

16. Diabetes

17. Systemic sclerosis (scleroderma)

18. Amyloidosis

19. Untreated thyroid disease

20. Chronic pulmonary disease

21. Severe renal insufficiency or renal failure

22. Current or recent history (within last 6 months) of: Diverticulitis, Duodenal or gastric ulcer, Acute pancreatitis, Ileus

• Contraindications to SmartPill® (in addition to above): Cardiac pacemaker, defibrillator, or other implanted electromagnetic device, Known Zenker'sdiverticulum, Dysphagia