• ≥12 and \<18 years old

• Patient weighs ≥18 kg at the time the patient provides written assent

• Females of child-bearing potential must have negative pregnancy test at Visit 1 (serum) and Visit 2 (urine) and confirm the use of appropriate contraception (including abstinence).

• Patient meets the Rome IV criteria for child/adolescent diagnosis of IBS-C

• Patient is willing to discontinue any laxatives used in favor of the protocol-permitted rescue medicine (which will only be allowed after 72 hours with no bowel movement)

• Patient meets the entry criteria assessed during the 2-week Screening period.

• Ability of both the patient and parent/guardian/LAR to communicate with the Investigator and to comply with the requirements of the entire study, including an understanding of the assessments in the eDiary and how to use the eDiary device

• Patient must provide written assent and the parent/guardian/LAR must provide written informed consent before the initiation of any study-specific procedures