Gut Reaction #21: Constipation
Constipation is a common condition that is more common in women and is generally defined by infrequent bowel movements (usually less than 3 stools per week) with the passage of hard stools with straining.
The 3 most common causes of constipation are irritable bowel syndrome (IBS-C), functional constipation (IBS without abdominal pain) and slow transit constipation (STC). In STC the colonic movement is abnormally slow whereas in IBS-C and functional constipation the colon moves normally. The best way to differentiate between these conditions is a colonic transit marker study. This is a non-invasive, painless and easy test of the movement of the colon assessed by measuring the number and distribution of tiny radio-opaque markers retained within the colon about 5 days after drinking them. In individuals with IBS-C or functional constipation a minority of markers will be seen on the abdominal X-Ray, whereas in patients with STC most of the markers will be retained.
The following may cause functional constipation or worsen pre-existing IBS-C or STC:
- Not eating enough fibre – such as fruit, vegetables and cereals
- Not drinking enough fluids
- Not exercising or being less active
- Ignoring the urge to go to the toilet
- Changing your diet or daily routine eg travelling
- Stress, anxiety or depression
- Drugs eg painkillers
In addition to the use of laxatives such as lactulose, Movicol (Laxido), docusate and senna, over the last few years new treatments have become available for the treatment of IBS-C and STC. I will briefly mention these in turn.
Linaclotide (please read Patient Information Sheet) is the first guanylate cyclase-C agonist available in the UK and may be prescribed to improve symptoms of abdominal pain, bloating and constipation in adults with moderate-to-severe IBS-C. It improves symptoms by decreasing sensitivity to abdominal pain (visceral sensitivity) and by increasing the amount of fluid in the intestines and increasing the speed that waste moves through the colon (accelerates transit). There is good evidence from large, well-conducted trials to suggest that people experience significant decreases in abdominal pain and bloating with improved stool frequency. Unfortunately, diarrhoea is a common side effect.
Another treatment for IBS-C is the pre-biotic called Orafti Inulin. Extracted from chicory root, high in inulin-type fructans, this can be added to food products, providing a high level of fibre and thus addressing one of the primary causes of constipation.
In patients with STC lubiprostone or prucalopride may be tried.
- Lubiprostone works by activating chloride channels in cells lining the gut, improving intestinal fluid secretion and increasing movement of the intestine. It leads to an increase in spontaneous bowel movements and decreases abdominal bloating, discomfort and straining.
- Prucalopride works by stimulating serotonin receptors in the bowel and increases colonic movement. It increases bowel movements, decreases bloating, discomfort and straining in most patients.
For more information about constipation or any of the above treatments, please do not hesitate to contact Dr. Adam Harris