• Bulk-forming: ispaghula husk, methylcellulose, sterculia and frangula
• Osmotic: lactulose and macrogols (polyethylene glycols)
• Stimulant: bisacodyl, senna and sodium picosulfate

In depth

• Adjust any constipating medication, if possible.
• Advise the person about increasing dietary fibre, drinking an adequate fluid intake, and exercise.
• Offer oral laxatives if dietary measures are ineffective, or while waiting for them to take effect.
• Start treatment with a bulk-forming laxative (adequate fluid intake is important).
• If stools remain hard, add or switch to an osmotic laxative.
• If stools are soft but the person still finds them difficult to pass or complains of inadequate emptying, add a stimulant laxative.
• Advise the person that laxatives can be stopped once the stools become soft and easily passed again.

In depth

• Begin by relieving faecal loading/impaction, if present.
• Set realistic expectations for the results of treatment of chronic constipation.
• Advise people about lifestyle measures — increasing dietary fibre (including the importance of regular meals), drinking an adequate fluid intake, and exercise.
• Adjust any constipating medication, if possible.
• Exclude underlying causes (e.g. hypothyroidism, metabolic disease, anal fissure, haemorrhoids).
• Laxatives are recommended:
• If lifestyle measures are insufficient, or whilst waiting for them to take effect.
• For people taking a constipating drug that cannot be stopped.
• For people with other secondary causes of constipation.
• As 'rescue' medicines for episodes of faecal loading.
• Laxatives are used as in short-duration constipation.
• Adjust the dose, choice, and combination of laxative to produce comfortable defecation with soft, formed stools once or twice a day.

In depth

• For hard stools, consider using a high dose of an oral macrogol (licensed for use in faecal loading/impaction).
• For soft stools or, for hard stools, after a few days treatment with a macrogol, consider starting or adding an oral stimulant laxative.
• If the response to oral laxatives is insufficient or not fast enough, consider:
• Using a suppository: bisacodyl for soft stools; glycerol alone or glycerol plus bisacodyl for hard stools.
• Using a mini enema — docusate (softener and weak stimulant) or sodium citrate (osmotic).
• If the response is still insufficient:
• Consider using a sodium phosphate or arachis oil retention enema (place high if the rectum is empty but the colon is full).
• For hard faeces it can be helpful to give the arachis oil enema overnight before giving a sodium phosphate (large volume) or sodium citrate (small volume) enema the next day.
• Enemas may need to be repeated several times to clear hard impacted faeces.
• The choice depends on individual preference and what has previously been tried.
• Regular use of a laxative may be needed after the faecal loading/impaction has been cleared.

In depth

• Laxatives can be slowly withdrawn when regular bowel movements occur without difficulty.
• Laxative medication should not be suddenly stopped.
• If a combination of laxatives has been used, reduce and stop one laxative at a time. Begin by reducing stimulant laxatives, increasing the dose of the osmotic laxative if necessary.
• It can take several months to be successfully weaned off all laxatives.
• Relapses are common and should be treated early with increased doses of laxatives.
• Laxatives need to be continued long term for:
• People taking a constipating drug that cannot be stopped.
• People with a medical cause of constipation.

In depth