Chronic idiopathic (not due to underlying disease) constipation is defined as 2 or more of the following symptoms for at least 6 months: straining; lumpy or hard stools; a sensation of incomplete evacuation; a sensation of obstruction or blockage, and/or less than 3 spontaneous bowel movements/week.

It activates chloride channels in cells lining the gut, improving intestinal fluid secretion and increasing movement of the intestine.

In high quality clinical trials lubiprostone led to an increase in spontaneous bowel movements in about 60% of patients. Abdominal bloating, discomfort, stool consistency and straining also improved with lubiprostone.

One 24 microgram capsule should be swallowed whole (with water) and taken with food twice daily. The same dose may be used in older patients or in those with kidney or liver problems. The drug should be avoided in patients with known fructose intolerance (it contains sorbitol).

The benefits of lubiprostone should be evident within 24 hours in most patients. If treatment is not effective within 2 weeks it should be stopped.

The initial course of treatment is 2 weeks. It has been used for up to 12 months in clinical trials without any loss of benefit in those that initially responded. Stopping treatment did not lead to any worsening of pre-existing symptoms (no “rebound effect”).

Most patients do not suffer any side effects with this treatment. Nausea is the commonest side effect and this may be lessened by taking the capsule with a meal. Diarrhoea may occur and if severe, the treatment should be stopped. Shortness of breath or chest discomfort has been reported (< 2% of patients in trials) and tend to resolve within a few hours; if they recur the treatment should be stopped.

It is not recommended in pregnancy, in patients planning a pregnancy and should be avoided if breastfeeding.