Latest Treatment of IBS with Constipation (IBS-C)

The Latest Treatment of IBS with Constipation is discussed here. It is important to treat concomitant anxiety and use adequate dietary fiber before initiating these novel drugs.

IBS overview:

Irritable Bowel Syndrome (IBS) is a very common condition that primarily affects young individuals. It is a chronic idiopathic condition that is defined as recurrent abdominal pain occurring at least once a week for the last three months with two or more of the following features:

  • the pain is associated with or relieved with defecation
  • the pain is associated with a change in the consistency of stools
  • the pain is associated with a change in the frequency of stools.

IBS has no underlying organic etiology. It is a functional disorder and patients usually complain of abdominal pain, bloating, abdominal cramps, alternating bowel habits, constipation, diarrhea, flatulence, and anxiety.

IBS is divided into four different categories based on the associated abdominal symptoms and stool frequency:

  • IBS with Diarrhea
  • IBS with Constipation
  • IBS with mixed symptoms
  • Unclassified IBS

Latest Treatment of IBS with Constipation:

The initial treatment of patients with IBS associated with predominant symptoms of constipation includes a trial of soluble fiber followed by polyethylene glycol.

Patients with persistent symptoms despite these treatments may use any of the following latest treatment of IBS:

  • Lubiprostone (Amitiza)
  • Linaclotide (Linzess, Constella)
  • Plecanatide (Trulance)
  • Tegaserod (Teganorm)
  • Tenapanor (IBSrela)

Lubiprostone (Amitiza) for IBS-C (IBS with predominant symptoms of Constipation):

Lubiprostone is a novel medicine approved for the treatment of irritable bowel syndrome with predominant symptoms of constipation. It has a unique mechanism of action. It activates type 2 chloride channels in the intestinal surface cells resulting in water and fluid secretion into the intestinal lumen. It also has a dose-dependent effect on the smooth muscles of the intestine causing them to contract and propel the food forward.

It increases the tone of the pylorus resulting in fasting gastric fullness. This effect is partially responsible for nausea associated with this drug. However, this effect has not been observed after a meal or a full stomach.

It is also approved for the treatment of patients with severe long-standing constipation. However, unlike its use in patients with irritable bowel syndrome, higher doses (24 mcg) are required to treat patients with chronic constipation. In IBS-C, lower dose of 8 mcg are recommended.

Avoid in inflammatory bowel disease and intestinal obstruction

Linaclotide (Linzess, Constella) for IBS-C (IBS with constipation):

Linaclotide (Linzess) acts by activating guanylate cyclase C receptors in the intestine. It does not enter the systemic circulation and is metabolized in the gastrointestinal tract. It is approved for the treatment of moderate to severe constipation especially when associated with irritable bowel syndrome. It also relieves visceral pain and intestinal cramps.

It should be avoided in patients with intestinal obstruction and inflammatory bowel disease. Overdose may result in severe diarrhea, dehydration, electrolyte imbalance especially hypokalemia, and hypotension.

use in children younger than 6 years has resulted in death due to dehydration

Plecanatide (Trulance) for IBS-C (IBS with constipation):

Plecanatide (Trulance) has a similar mechanism of action as linaclotide. It activates intestinal guanylate cyclase C receptors resulting in fluid secretion into the intestine. Like linaclotide, it also relieves visceral pain that is one of the main symptoms of patients with IBS.

It has similar side effects as linaclotide and should be avoided in young children as it can cause severe dehydration and death.

Tegaserod for IBS-C (IBS with constipation):

Tegaserod is a 5 hydroxytryptamine receptor agonist (5 HT4 agonist) that increases colonic motility and relieves abdominal pain associated with patients with IBS-C. It also improves symptoms of dyspepsia in patients with IBS.

Tegaserod should be avoided in old patients as the efficacy and safety in old age has not been established. It should be avoided in patients with ischemic colitis, patients with intestinal adhesions or bowel obstruction, severe gall bladder disease, and patients with sphincter of Oddi dysfunction.

It may be used as an alternative drug especially in women who are younger than 65 years of age and in patients who have IBS with mixed symptoms. Tegaserod may be used in patients who have failed a trial of polyethylene glycol.

Tenapanor (IBSrela) for IBS-C:

Tenapanor is a sodium-hydrogen exchanger 3 inhibitor. It acts by inhibiting the absorption of sodium and phosphate, increasing intestinal fluid, and intestinal transit.

It improves stool consistency and relieves visceral pain. It should be avoided in patients who develop abdominal distension, diarrhea, dehydration, and hypotension.

Read: Medicines used to treat constipation

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