Effect of Lubiprostone on Methanogenesis and Bowel Function in Chronic Constipation.

• Lubiprostone (Drug): Colonic 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.
• Lubiprostone Control (Drug): Colonic 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.

Primary outcomes

• Change in Methane Production [Baseline and 1 month]: Change in the mean area under the curve of the breath hydrogen and methane gas profiles in parts per million, from time 0 to 120 minutes, between baseline versus mean area under the curve at the end of study.

Secondary outcomes

• Stool Frequency (Complete Spontaneous Bowel Movements) [Baseline and 1 month]: change in mean stool frequency (delta) between baseline week and final week of study
• Percentage Change in the Colonic Transit Time [Baseline and 1 month]: Percentage change of colonic transit time between the baseline colonic transit study and the colonic transit study at the end of study
• Peak Methane Value [Baseline and 1 month]: The peak methane value measured during the baseline breath study will be compared with the peak methane obtained at the end of study breath test

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Constipation as defined by Rome III criteria13. Patients must have symptoms > 3 days/month for the past three months and report at least two of the following symptoms ≥ 25% of the time: straining, lumpy or hard stool, sensation of incomplete evacuation, sensation of anorectal obstruction/blockage, use of manual maneuvers, < 3 bowel movements/week. Also,they should have insufficient criteria for IBS, and only rarely loose stools without the use of laxatives.
* ≥ 3 ppm methane value at baseline1, 2(before sugar load).

Exclusion Criteria:

* Patients taking drugs that are known to be constipating will be excluded or asked to discontinue medications for at least 2 weeks and reassessed. For example, we will recommend that patients taking calcium channel antagonists contact their respective primary care physicians to explore alternative medications for hypertension such as beta blockers or ACE-inhibitors. If the calcium channel antagonists are able to be discontinued, patients will be re-screened at least two weeks after the medications are discontinued. If patients no longer meet inclusion criteria, they will be excluded from the study. Patients who remain constipated will be eligible for enrollment.
* Patients with co-morbid illnesses such as severe cardiovascular disease, chronic renal failure, or those with previous gastrointestinal surgery except cholecystectomy and appendectomy
* Patients with neurologic diseases such as multiple sclerosis, strokes, spinal cord injuries, and those who have problems with cognizance, i.e. a mini-mental score of <15 and/or are legally blind will be excluded.
* Women who are pregnant or are likely to conceive during the course of the study will be excluded. Urinary pregnancy tests will be performed on all women of child-bearing potential prior to enrollment and before any x-ray of the abdomen.
* Patients with Hirschsprung' s disease, or active local anorectal problems such as anal fissures, bleeding hemorrhoids, Crohn's, colitis, or colon cancer.
* Patients with alternating constipation and diarrhea and those who fulfill the Rome-III criteria for irritable bowel syndrome.
* Recent antibiotic use (last 6 weeks).
* Patients using laxatives, PEG or Tegaserod and unwilling to discontinue these medications at least 2 weeks prior to the study.

Participant flow

Outcome results

• Change in Methane Production (Primary), Mean, parts per million*minutes: Lubiprostone 10645 +/- 1481; Placebo 14635 +/- 2330
• Stool Frequency (Complete Spontaneous Bowel Movements) (Secondary), Mean, bowel movements per week: Lubiprostone 3.71 +/- 0.84; Placebo 0.85 +/- 0.54
• Percentage Change in the Colonic Transit Time (Secondary), Mean, percent: Lubiprostone 0.23 +/- 0.06; Placebo 0.48 +/- 0.1
• Peak Methane Value (Secondary), Mean, parts per million: Lubiprostone 51.3 +/- 7.1; Placebo 70.5 +/- 11.2

Adverse events

Other adverse events by term