Constipation

Constipation

Constipation is a common cause of distress. Prevention is better than waiting until treatment is needed.
Constipation should be anticipated in all patients taking opioids or anticholinergics (e.g. tricyclic antidepressants, cyclizine, etc) and those who are either inactive or have a reduced fluid or dietary fibre intake. Lack of privacy and pain may be contributing factors.

Effects of chronic constipation
Anorexia, occasional vomiting, colic, tenesmus, overflow diarrhoea, urinary retention, confusion.

TREATMENT OF EXISTING CONSTIPATION
Before prescribing laxatives for established constipation
•Rule out bowel obstruction. If bowel obstruction is suspected seek further advice
•Consider underlying causes e.g hypercalcaemia, drugs
 
In spinal cord compression:-
 
•If normal sphincter sensation and function is present, titrate laxatives as normal, avoid excessive softening
•If normal sphincter sensation and function is absent, bisacodyl or sodium acid phosphate (Carbalax) suppositories should be prescribed, aiming for a planned bowel action every two to three days
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LAXATIVES

•Laxatives should be prescribed on a regular basis as soon as weak or strong opioids are prescribed (except those with ileostomy or diarrhoea), with full explanation to the patient
•Relatively high doses may be needed – the laxative dose may need increasing as the dose of opioid is increased but this should be titrated to the individual’s requirements
•Many ill patients will not tolerate high fibre diet or bulk forming laxatives and these are not usually recommended in palliative care. Many patients become expert at adjusting their own laxatives. However a regular regime will be essential for those on opioids
•A combination of stimulant laxative with a softening/ osmotic agent is a good first choice (see tables below)
•25% of patients on oral laxatives may still need rectal measures at times
•In patients recognised to have significant and ongoing constipation as a result of opioid use despite measures above, specialist advice may be sought regarding the use of drugs such as the Oxycodone/Naloxone combination (Targinact®) see Oxycodone or the opioid antagonist methylnaltrexone (Relistor®)
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References

Joint Formulary Commitee (British Medical Association and Royal Pharmaceutical Company). British National Formulary (BNF 62). bnf.org 2011.

Twycross R, Wilcock A (Eds). Palliative Care Formulary: Fourth
Edition. Palliativedrugs.com Ltd 2011: pp 35–51.