Lubiprostone is a locally acting chloride channel activator that enhances a chloride-rich intestinal fluid secretion without altering sodium and potassium concentrations in the serum. Lubiprostone acts by specifically activating
ClC-2, which is a normal constituent of the apical membrane of the human intestine. By increasing intestinal fluid secretion, Lubiprostone increases motility in the intestine, thereby facilitating the passage of stool and alleviating symptoms associated with constipation. After administration, Lubiprostone and its metabolites are observed only on the apical (luminal) portion of the gastrointestinal epithelium. Additionally, activation of ClC-2 by Lubiprostone recovers mucosal barrier function via restoration of tight junction protein complexes. Lubiprostone relieves symptoms within 24 hours.