The Aword

GENERAL MEASURES:

• High Fibre Diet: increases the bulk of the stool and affects faecal transit time. About 30g per day - (e.g. fruit, vegetables, wholemeal bread, cereals and grain foods), should be tried for at least one month before effects on constipation are determined, although most will notice an effect within 3 to 5 days. If adequate fluid intake is not possible, avoid increasing dietary fibre. Side effects include flatulence, bloating and distension but should diminish after a few months, once the bowel has adjusted.
• 2 litres of water, taken each day (approx. 8 glasses/12 cups)
• High fibre is NOT recommended in patients with megacolon or
  hypotonic colon/rectum as it will not respond to bulk in the colon; and
  increasing bulk may lead to obstruction in those taking opioids.
• Coffee and tea have diuretic properties, therefore may make
  constipation worse.
• Exercise/ maintaining mobility if possible
  

High Fibre Diet: increases the bulk of the stool and affects faecal
transit time. About 30g per day - (e.g. fruit, vegetables, wholemeal bread,
cereals and grain foods), should be tried for at least one month before
effects on constipation are determined, although most will notice an effect
within 3 to 5 days.

If adequate fluid intake is not possible, avoid increasing
dietary fibre. Side effects include flatulence, bloating and distension but
should diminish after a few months, once the bowel has adjusted.

LAXATIVES:

Laxatives are non-absorbable chemicals or materials designed to increase
the bulk of the stool, or to lubricate passage of the stool, or to stimulate the
bowel wall either directly or indirectly.
 
Bulking agents such as Isphagula husk, Psyllium, may be used but
adequate fluid intake is essential to avoid obstruction.

Faecal softeners / emollient laxatives (e.g. docusate):

• soften the faeces by decreasing surface tension and allowing increased penetration of intestinal fluids into the faecal mass.
• Docusate sodium softens stool, but also has weak stimulant properties.
  Short-term use (up to 1 week) only is recommended.
• Rectal docusate may be useful for rapid relief, although should not be
  used for haemorrhoids or anal fissure.
• Faecal softeners, including some bulking agents, are useful in the
  management of haemorrhoids and anal fissure.
• Liquid paraffin is a stool softener/lubricant is not recommended as it
  can cause anal seepage and irritation, lipoid pneumonia (rarely, on
  aspiration) and malabsorption of lipid-soluble vitamins.
  

Osmotic laxatives (e.g. phosphate enemas):

• Retain fluid in the bowel by osmosis or changing water distribution in
  the faeces. It is important that good fluid intake be maintained.
• Lactulose increases faecal volume and bowel movements. It should be
  taken regularly and takes 2 days (or more) to have an effect. It is
  therefore unsuitable for rapid relief of constipation.
• Side effects include abdominal pain and bowel distension.
• Rectal preparations of phosphates and sodium citrate (use occasionally
  to avoid sodium and water retention) and oral magnesium salts are
  useful when quick relief is desirable. Phosphate enemas are used most
  often for bowel clearance prior to surgery, sigmoidoscopy etc.
  

Stimulant laxatives (e.g. senna, bisacodyl):
 
Directly stimulate colonic nerves to cause movement of the faecal mass.

• Effect is usually within 6- 12 hours, therefore it is recommended as a
  bedtime dose.
• Suppositories act within 20 to 60 minutes.
• Side effects: Abdominal cramp is the most common immediate side
  effect. Electrolyte (salt) disturbances and reduced colonic tone (atonic) may result from chronic use. It is therefore inadvisable to use stimulant laxatives over a long period of time.
• The Committee on Safety of Medicines has advised that
  danthron be restricted to use for constipation in terminally ill patients
  because of accumulating evidence confirming genotoxicity [CSM, 2000].
  

TIME FOR ORAL LAXATIVES TO BE EFFECTIVE:

• bulk-forming : e.g. methylcellulose/Psyllium: 2-4 days
• lubricants/softeners: e.g. mineral oil/docusate : overnight
• osmotic diuretics: e.g. magnesium citrate, sodium phosphate : 3-6 hours
• intestinal stimulants: e.g. senna, bisacodyl: 6-12 hours (overnight)