For further information (including contraindications) refer to British National Formulary.
| Stimulants – stimulant laxatives increase intestinal motility (can often cause abdominal cramp). |
| Senokot
Mode of action: irritates the bowel mucosa promoting evacuation. Acts in 8-12 hours. Docusate sodium (for example Dioctyl) Mode of action: acts by reducing surface tension by allowing penetration of water/fats into hardened faeces and so reduces straining at stool. Acts in 1-2 days. |
| Osmotics – increase the amount of water in the large bowel, either by drawing fluid from the body into the bowel or by retaining the fluid administered with the medication. |
| Polyethylene glycol (PEG) (for example Macrogol oral powder)
Mode of action: acts by retaining water within the bowel making the stool soft. Can be used to treat faecal impaction (see BNF for regime). Lactulose Mode of action: Lactulose is a sugar which the body cannot digest. As it passes through the bowel it attracts and retains water making the stool soft. Requires adequate fluid intake to be effective. |
| Bulk forming supplements and laxatives Mode of action: increases faecal mass which stimulates peristalsis. Patients should be advised that the full effect may take some days to develop. Can be useful in treating faecal urgency or in symptoms related to diagnosed Irritable Bowel Syndrome. |
| Types of fibre:
· Insoluble fibre (for example Bran) · Ispaghula husk (for example Fybogel) Mode of action: see bulk forming laxatives. Both of the above require adequate fluid intake to be effective. If inadequate fluids will cause/increase constipation. · Soluble fibre (for example Optifibre) – less dependent on fluid intake. |
| Anti-diarrhoeal/anti-mobility medication – relieves symptoms of acute diarrhoea and can be used with caution in faecal incontinence only when underlying cause of incontinence has been addressed.
· Loperamide hydrochloride is the first drug choice. (Consider syrup for low doses less than 2mg, easier to titrate dose to minimise risk of constipation). |
| Rectal preparations |
| Micro-enemas/suppositories
· Sodium citrate (for example Microlax, Microlette) Mode of action: acts by retaining fluid in the bowel by osmosis or by changing the pattern of water distribution in the faeces. · Bisacodyl suppositories Mode of action: acts on contact with large bowel mucosa to produce a soft stool. · Glycerine suppositories Mode of action: acts as rectal stimulant by virtue of mild stimulant action of glycerol. Large volume enemas (should be used with caution only after consideration of micro-enemas and suppositories). · Phosphate enema (for example Fleet enemas) · Arachis oil (faecal softener) |