Constipation and bowel cleansing

Question 1

Constipation is

Answer 1

the EVACUATION OF HARD STOOLS LESS FREQUENTLY THAN IS NORMAL for an individual.

• It can occur at any age and is commonly seen in women, the elderly and during pregnancy.

Question 2

Constipation lifestyle advice

Answer 2

Fibre intake, adequate fluid intake and exercise is advised. Fruits high in fibre and sorbitol, and fruit juices high in sorbitol can help prevent and treat constipation.

Question 3

Laxative abuse

Answer 3

Laxative abuse can lead to hypokalaemia, so they should only be given if straining to defecate will exacerbate the condition e.g. angina.

Question 4

General side effect for all Laxatives is

Answer 4

Abdominal pain

Question 5

Bulk-forming Laxatives - Examples include

Answer 5

bran, ispaghula husk, methylcellulose and sterculia. They increase faecal mass causing peristalsis

Question 6

Bulk-forming Laxatives - onset of action is

Answer 6

Onset of action is up to 72 hours. Adequate fluid intake must be maintained to avoid intestinal obstruction. Advise patients to not take immediately before bed.

Question 7

Stimulant laxatives - Examples include

Answer 7

bisacodyl, sodium picosulfate, senna, co-danthramer and co-danthusate.

Question 8

Stimulant laxatives - onset of action

Answer 8

Very fast acting: Senna (8-12 hours), Bisacodyl (10-12 hours)

Question 9

Avoid stimulant laxatives in

Answer 9

They increase intestinal motility, but often cause abdominal cramp, so avoid in intestinal obstruction.

Question 10

Co-danthramer and Co-docusate should only be used

Answer 10

in the terminally ill, due to carcinogenicity and genotoxicity.

Question 11

Faecal softeners onset of action

Answer 11

within 15 mins - fastest!

Question 12

Faecal softeners - These drugs increase

Answer 12

penetration of intestinal fluid into the faecal mass –> Docusate sodium + Glycerol. An example is Arachis oil… hence peanut allergy.

Question 13

Faecal softeners example

Answer 13

Liquid paraffin has been used as a lubricant for the passage of stools, but manufacturer advises that it should be used in caution due to its adverse effects: anal seepage, risk of G.I. disease + pneumonia.

Question 14

Osmotic laxatives

These drugs increase & examples

Answer 14

the amount of fluid in the large bowel and a prime example is LACTULOSE. Interestingly, it can also be used to treat hepatic encephalopathy.
- Another example is macrogol 3350 with potassium chloride, sodium bicarbonate and sodium chloride.

Question 15

Managing Short-term constipation - 1st & 2nd line

Answer 15

1st Line: Bulk-forming laxative ensuring adequate fluid intake
2nd Line: If stools remain hard, add to or switch to an osmotic laxative
If stools are soft but difficult to pass/person complains of inadequate emptying, a Stimulant laxative should be added.

Question 16

Opioid induced constipation

Answer 16

 Osmotic laxative (or docusate sodium to soften stools) + Stimulant laxative is recommended
Bulk-forming laxatives

 Methylnaltrexone bromide + Naloxegol can be used when the response to other laxatives is inadequate. In palliative care, this drug should be used as an adjunctive to existing laxative therapy.

Question 17

Chronic constipation

Treatment should be started with

Answer 17

a bulk-forming laxative whilst ensuring good hydration.

If stools remain hard, add or change to an osmotic laxative such as macrogol. If macrogols are ineffective or not tolerated… Lactulose can be given.
If the response is inadequate, a stimulant laxative can be added.
 If atleast 2 laxatives from different classes have been tried at the highest tolerated doses for 6 months, the use of prucalopride (in women) should be considered.
 If regular bowel movements have been achieved, reduce and STOP 1 LAXATIVE AT A TIME. If possible, reduce the stimulant laxative first. But it may be necessary to also adjust the osmotic laxative dose to compensate.

Question 18

Constipation in pregnancy and breastfeeding

Answer 18

If dietary and lifestyle changes FAIL to control constipation in pregnancy, fibre supplements in the form of bran/wheat are clinically safe and effective.

A Bulk-forming laxative is first-line during pregnancy if fibre supplements fail. An osmotic laxative e.g. lactulose can also be used.

Bisacodyl or Senna can be used if a stimulant effect is necessary, but SENNA SHOULD BE AVOIDED NEAR TERM or if there is a history of unstable pregnancy.

 Stimulant are more effective than Bulk-forming laxatives… but they are more likely to cause side effects  diarrhoea and abdominal discomfort. Docusate and glycerol suppositories can be used.
 A bulk-forming laxative is first-line during breast-feeding, if dietary measures fail. Lactulose or Macrogol can be used if stools remain hard. As an alternative, a short course of stimulant laxative such as Bisacodyl or Senna can be used.

Question 19

Constipation in children

Answer 19

The first-line treatment for children with constipation is a laxative IN COMBINATION with dietary modification (juice containing sorbitol such as apple, pear or orange).

An increase in dietary fibre, adequate fluid intake and exercise is advised.

Diet should be well balanced and contain: fruits, vegetables, high-fibre bread, baked beans + wholegrain breakfast cereals.
Unprocessed bran can cause bloating, flatulence and reduced absorption of micronutrients.
 If faecal impaction is not present/been treated, first-line laxatives are a macrogol (e.g. macrogol 3350 with KCL, Sodium Bicarbonate and Sodium chloride).
 If there is an inadequate response/poorly tolerated add or change to a stimulant laxative
 If stools remain hard, lactulose or another laxative with softening effects e.g. docusate sodium can be added.

Question 20

Chronic constipation in Children

Answer 20

• Laxatives should be continued for several weeks after a regular pattern of bowel movements.
• The dose of laxatives should then be gradually tapered over a few months.

Question 21

Faecal impaction in children

Answer 21

• In children over 1 years old, an oral preparation containing a macrogol (e.g. macrogol 3350 with potassium chloride, sodium bicarbonate and sodium chloride) is used to clear faecal mass + establish and maintain soft well-formed stools.
• If disimpaction does not occur after 2 weeks a stimulant laxative can be added, or if stools are hard used in combination with an osmotic laxative such as lactulose.

Question 22

Osmotic laxative examples

Answer 22

• lactulose
• macrogol 3350
• magnesium hydroxide

Question 23

Stimulant laxative examples

Answer 23

• bisacodyl
• senna
• glycerol suppos.
• docusate
• co-danthrusate
• co-danthramer
• sodium picosulfate

Question 24

Opioid induced constipation -

Answer 24

• naloxegol

- methylnaltrexxone

Question 25

Constipation red flags

Answer 25

• new onset >50y, unexplained weight loss, anaemia, blood in stools, abdominal pain

Question 26

selective 5HT-4 agonist

Answer 26

Prucalopride

• Used in women only when two or more laxatives have been used at the highest tolerated doses and not been effective for atleast 6 months.

Question 27

excessive stimulant use can cause

Answer 27

• hypokalemia
• lazy bowel
• diarrhoea

Question 28

senna colour

Answer 28

colours urine brown/yellow