Any significant change in bowel habit needs to be assessed.

After assessment treatment with laxatives may be required.

 

Background:

Laxatives use many different mechanisms of action to increase bowel frequency and consistency.

“Bulking up” the stool with fibre is a useful long term approach in simple uncomplicated constipation.

Stool softening agents have a role to play when the stool bolus is hard and uncomfortable to pass, particularly if pain around the back passage is a problem (anal fissures or tears, haemorrhoids, recent surgery).

“Osmotic agents” work by drawing water into the stool and thereby softening it and speeding progress along the bowel.

“Stimulant laxatives” treat constipation by stimulating the nerve endings in the bowel wall and increasing muscular propulsive activity.

Which laxative should I use?

The choice of laxative depends on the type of constipation.

The person with a sudden onset of severe rock-hard difficult stools needs stool softening  agents or osmotic agents initially.

The person who gives a long history of variable bowel habit, tending to frequent bouts of  constipation should start with simple fibre supplements, moving on to osmotic agents if   required.

The person with a long history of very difficult constipation, perhaps having a call to toilet only once a week, should avoid excessive fibre supplementation. This situation will probably require a combination of osmotic and stimulant agents.

The person who has reasonably frequent toileting but describes difficulty evacuating the  bowel motion needs to achieve a soft but bulky motion to allow the best condition for  pelvic floor muscle action.

 

They didn’t work!

If the lower end of the bowel is full of a “tower” of hard difficult stool it may be impossible for any oral agent to help initially. Sometimes it will be necessary to use suppositories or enema given through the back passage to clear this obstruction before restarting with oral agents to avoid the same hold-up occurring again.    Many mild laxatives may take 3 days before any effect is noticed.

The bowel walls often distend over time if constipation has been a significant problem for years. The walls have less muscular tone as a result. It may take months or even 1-2 years to regain this tone if the bowel habit is then managed effectively. Have patience. Years of straining at stool can cause further problems by weakening the pelvic floor. This may need intensive muscle strengthening exercises in addition to stool modification to improve function.

 

Side-effects?

Flatulence and bloating is a common side effect of many laxatives. Paraffin can cause fat soluble vitamin malabsorption if used long term. The young and the elderly are not suitable for the “extreme” osmotic agents which may cause electrolyte disturbance and kidney problems. Long term use of stimulant laxatives often leads to tolerance and increasing doses are needed to achieve a result. It is not known whether any long term damage to the nerves in the bowel wall is definitely caused by these agents.

 

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TYPES OF LAXATIVES

RECOMMENDED FOR LONG TERM USE IF REQUIRED

 

Commercial Fibre Products

Proprietary Name

Ispaghula	Fybogel, Agiofibe
Psyllium	Metamucil, Agiofibe, Nucolox
Guar gum	Benefibe
Sterculia	Normafibe

               

           Poorly absorbed ions

Osmotic Laxatives

Proprietary Name

Magnesium hydroxide	Uro-Mag, Milk of Magnesia
Magnesium citrate	Citroma
Magnesium Sulphate	Epsom Salts
Sodium phosphate  Sodium picosulphate**	Fleet bowel prep/enema, PicoPrep,  Picolax  **stimulant as well!

 

 

           Poorly absorbed sugars/polysaccs

 

Lactulose	Actilax, Duphalac
Polyethyleneglycol	Movicol, Glycoprep, Colonlytely
Sorbitol	Cystosol, Sorbilax
Glycerol	Glycerin suppositories

       

 

  ADVISE SHORT TERM USE ONLY:

            Stimulant Laxatives                                  Proprietary Name

            Anthraquinones

Cascara sagrada	Natures Remedy Tablets
Senna	Senokot, Laxettes, Nu-Lax
Frangula bark	Normacol Plus
Castor Oil

            Diphenylmethane derivatives

Bisacodyl

Durolax, Bisalax

 

            Emollients (Stool Softeners)                     Proprietary Name

Docusates	Colace
Mineral Oil	Fleet Mineral Oil
Paraffin Oil	Parachoc, Agarol
Poloxamer	Coloxyl Drops