Irritable Bowel Syndrome with Constipation

Diagnosis

The American Gastroenterological Association recommends that a diagnosis of IBS-C requires abdominal pain associated with defecation or a change in bowel habit, symptoms present for more than 6 months, and hard stools predominating (>25% of bowel movements) 1, 3
The European Society of Gastrointestinal Motility suggests that IBS-C patients often experience a sense of incomplete evacuation 1

The National Institute for Health and Care Excellence recommends soluble fiber (e.g., ispaghula) as a first-line treatment for IBS-C, starting at low doses (3-4g/day) and gradually increasing to avoid bloating 4
The American College of Gastroenterology suggests that regular exercise and dietary modifications should be advised for all IBS patients, including those with IBS-C 4
The European Society of Gastroenterology recommends linaclotide, a guanylate cyclase-C agonist, as a second-line treatment for IBS-C, although diarrhea is a common side effect 5
The American Gastroenterological Association suggests that tricyclic antidepressants may be effective for global symptoms and abdominal pain in IBS-C, starting at low doses (e.g., 10mg amitriptyline once daily) and titrating slowly to 30-50mg once daily 7

The British Society of Gastroenterology notes that IBS is a diagnosis of exclusion, and alarm features (age >50 years, weight loss, nocturnal symptoms, rectal bleeding, family history of colon cancer, anemia) warrant further investigation 1, 8
The World Gastroenterology Organisation suggests that many IBS-C patients may eventually alternate between constipation and diarrhea if followed long enough, potentially changing their subtype classification 3
The American College of Gastroenterology recommends that treatments for IBS-C often cause diarrhea as a side effect, requiring careful titration and monitoring 5