What is constipation?

Constipation is the infrequent or difficult, sometimes painful passage of hard, dry bowel movements. There is no right number of bowel movements per day in healthy people - for some people normal may be three times a day and for others it may be twice a week. A change in the usual pattern of bowel movements, for example, from once a day to once a week, or difficulty in passing stools usually indicates constipation. Constipation is more common among women, children and people over 65.

What are the symptoms of constipation?

As mentioned previously, the most common symptom of constipation is a change in the usual pattern of passing stools, most often an increase in time between each movement. Because the stools become hard and dry there is usually difficulty and sometimes pain in passing stools. If there is constant straining to pass a stool the veins in the anus may become swollen and irritated causing haemorrhoids or "piles". These can be uncomfortable and cause bleeding.

What causes constipation?

A lack of roughage or fibre in the diet or insufficient liquid intake can lead to constipation. The colon removes water as waste products move through it. If the contractions of the muscle of the colon are slow or sluggish the stool may pass slowly allowing too much water to be absorbed, causing hard, dry stools. Lack of exercise can also be a factor and constipation often occurs in older people with poor mobility.

Some medications (eg, strong painkillers) can cause constipation. Certain diseases such as multiple sclerosis, problems with the colon and rectum, stroke, spinal cord injuries, diabetes and thyroid problems can also cause constipation. Pregnant women often complain of constipation and it is a common problem following surgery.

Are any tests necessary?

A physical examination and medical history are usually sufficient for a doctor to diagnose constipation. If there is blood in the stools, recent changes in bowel movements or weight loss, tests may be necessary.

The tests may include a stool test, a barium enema x-ray or colonoscopy - these tests will only be used if your symptoms are very severe. If you need to have any of these tests your doctor will explain to you what is involved.

What treatment is available?

A change in diet is an important factor in managing constipation as a diet that is low in fibre is the most common cause of the condition. Laxatives or enemas may be prescribed for a short time, although for constipation associated with certain chronic (longlasting) conditions long-term laxative treatment may be recommended. There are several different types of laxatives and enemas available.

Bulking agents contain fibre and work by absorbing water into the stool. They are usually available as powder or granules containing ispaghula (eg, Fybogel®), methylcellulose (eg, Celevac®) or sterculia (eg, Normacol®).

Faecal softeners can be useful for people with haemorrhoids and usually contain docusate sodium (eg, Dioctyl®, Docusol®). These are usually given as capsules or liquid although a docusate sodium enema is also available (Norgalax®). 

Osmotic laxatives retain water in the bowel and soften the stools. They need to be taken with plenty of water and include magnesium salts (eg, Magnesium Hydroxide Mixture, Phillips' Milk of Magnesia®), macrogol (eg, CosmoCol®, Klean-Prep®, Laxido Orange®, Macilax®, Molaxole®, Movicol® and Moviprep® powder) and lactulose (eg, Lactugal® liquid). Glycerol suppositories have a gentle action and are often given to the elderly and children, or prior to surgery.

Stimulant laxatives speed up intestinal movement and are only used in the short term. They may be given prior to an examination such as a sigmoidoscopy or if the bowel is very full and bulking agents have not been effective. They can cause stomach cramps and should not be taken in pregnancy or if there is an intestinal obstruction. Stimulant laxatives include senna (available as tablets or liquid [Senokot®]), bisacodyl (available as tablets or suppositories) and sodium picosulfate (Dulcolax Pico Liquid®).

Other treatments may be given in certain circumstances. Lubiprostone (Amitiza®) is taken for two weeks; it is prescribed when dietary changes and other non-drug measures are inappropriate or don't work well enough. Prucalopride (Resolor®) can be given to people who do not respond to laxatives. Linaclotide (Constella®) can be considered in patients with constipation associated with irritable bowel syndrome (IBS). Methylnaltrexone (Relistor®) and naloxegol (Moventig®) can be used to treat constipation caused by taking strong painkillers called opioids, when other laxatives don't work.

If you have severe constipation you may be prescribed an enema, which will produce a quick response. If the stools are very hard they may become impacted and cause discomfort and the intestinal tract can become blocked temporarily. An enema may also be given prior to childbirth or surgery. An enema usually contains an osmotic laxative in the form of sodium or magnesium salts. An enema will usually be prescribed by your doctor but there are some that are available to buy in a pharmacy, including Cleen®, Micolette®, Micralax®, Phosphates enema BP, and Relaxit®. Arachis (peanut) oil is another type of enema that is available to treat faecal impaction; it should not be used in people who are allergic to soya or peanut. 

Self-help measures:

  • Eat a high-fibre diet with plenty of fluids.
  • Increase your daily exercise to help maintain regular bowel movements.
  • Never ignore your body's urge to have a bowel movement.
  • If you do become constipated, increase your intake of fibre and liquids like fruit juice. Coffee and some soft drinks that contain caffeine tend to have a dehydrating effect.
  • Try not to become preoccupied with your bowel movements.
  • Do not take laxatives regularly unless prescribed by your doctor.

Further information available from:

3 St Andrews Place
Tel: 020 7486 0341

Fact sheet provided by MIMS

Date last reviewed: September 2016

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