DOSING: To lower the risk of constipation, LOTRONEX should be started at a dosage of 0.5 mg twice a day. Patients well controlled on 0.5 mg twice a day may be maintained on this regimen. If, after 4 weeks, the 0.5-mg twice-daily dosage is well tolerated but does not adequately control IBS symptoms, then the dosage can be increased to up to 1 mg twice a day, the dose used in controlled clinical trials. LOTRONEX should be discontinued in patients who have not had adequate control of IBS symptoms after 4 weeks of treatment with 1 mg twice per day. LOTRONEX should be used with caution in debilitated patients, elderly patients, patients with mild or moderate hepatic impairment, and patients taking medications that decrease gastrointestinal motility. LOTRONEX should not be used in patients with severe hepatic impairment.