Several outcomes were measured but the most rigorous was one stipulated by the FDA: that the patient reported an improvement of at least 30 percent in abdominal pain and an increase of at least one bowel movement each week for six to 12 weeks, among other gauges.
About one-third of participants taking Linzess experienced the FDA-specified improvements, including less pain and increased bowel movements, versus 14 percent of those in the placebo group, the investigators found.
On average, participants reported about 43 percent improvement in abdominal pain by the end of the treatment period, along with easing of other symptoms such as cramping and bloating. The improvements started almost right away.
The second trial looked at 800 patients randomly assigned to the same dose of Linzess or a placebo, this time for 12 weeks. Again, about one-third of patients taking Linzess reported improvements in pain and constipation versus 21 percent in the placebo group.
When patients were later switched from linaclotide to a placebo, their symptoms returned, the researchers found.
The main side effect was diarrhea, the study authors, led by Dr. Satish Rao, of Georgia Health Sciences University in Augusta, noted in the report.
Linzess is believed to work by stimulating the secretion of chloride and water in the intestine. This helps soften the stool and stimulate contractions that can lead to bowel movements, Chey explained.
Commenting on the research, Dr. Timothy Pfanner, a gastroenterologist and assistant professor of internal medicine at Texas A&M Health Science Center College of Medicine, said: "This is a really interesting drug in that it works differently than anything else we have. It basically acts on some nerve receptors and stimulates them to inhibit the pain response and reduces bloating and increases motility," he added.
"There are lots of drugs out there for constipat
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