The U.S. FDA approved a 72 microgram dose of Ironwood Pharmaceuticals Inc. and Allergan PLC's LINZESS for the treatment of chronic idiopathic constipation in adults.

The new dose is expected to be available in the first quarter of 2017. Approval of the new dose was based on the results of a phase 3 trial of 1,223 adults with the disease.

LINZESS is now FDA-approved in three dosages: 290 mcg for patients with irritable bowel syndrome with constipation, and 145 mcg and 72 mcg for adults with chronic idiopathic constipation.