2. Constipation

Question 1

Constipation symptoms

Answer 1

• Dry, hard or lumpy stools
• Straining
• Lower abdominal pain or bloating

Question 2

Constipation red flag symptoms

Answer 2

New onset 50+
Anaemia
Abdominal pain
Weight loss
Blood in stool

Question 3

Constipation treatent

Answer 3

1. Lifestyle measures, e.g increasing fibre intake, increasing water intake

If dietary measures fail try Oral laxatives:
* 1st line: Bulk-forming laxatives
* 2nd line: If stools remain hard, add or switch to osmotic laxative
* 3rd line: If stools are soft or difficult to pass or incompleting emptying, offer stimulant laxative

B.O.S
B- bulk-forming laxative
O- osmotic laxative
S- stimulant laxative

Question 4

Constipation definition

Answer 4

Bowel movements that occur less than 3 times a week

Question 5

List of laxatives

Answer 5

Bulk-forming
* Ispaghula husk
* Methylcellulose
* Bran

Osmotic
* lactulose
* Macrogol 3550
* Magnesium hydroxide

Stimulant
* Glycerol suppositories
* Senna
* Docusate sodium
* Sodium picosulfate
* Bisacodyl

Question 6

Bulk-forming laxatives mechanism of action

Answer 6

Imititate fibre in the diet and swell in the present of water. Larger stools sitmulate peristalsis.

Usually work after 24 hours, but may take 3 days to have full effect

Question 7

Bulk-forming laxatives side effect

Answer 7

• Intestinal obstruction
  Patients must drink adequate fluids, must swallow with water and not take before bed
  contraindicated: narrow intestines, reduced mobility, elderly , higher risk of intestinal obstruction
• Bloating and flatulence
• Cramping
• Hypersensitivity (isphaghula husk) –> allergic rhinitis, bronchospasms, allergic conjuctivitis

Question 8

Osmotic laxative mechanism of action

Answer 8

Drawing water from the body and retain water to soften hard stools and maintain their size

Question 9

Osmotic laxatives onset of action

Answer 9

Lactulose - starts working in 48 hours
Macrogol - starts working in 2-3 days

Question 10

Osmotic laxatives side effects

Answer 10

• Diarrhoea, bloating, flatulence, cramps, nausea (common with lactulose)
• Dehydration

Question 11

Stimulant laxatives mechanism of action

Answer 11

Stimulate intestinal motility to help stool move along the tract

Takes 6-12 hours to work.
Can be taken in the evening , patients can then go to the toilet in the morning

Question 12

Glycerol suppositories onset of action

Answer 12

Glycerol suppositories take 15-30 minutes to work. They only empty stool in the rectum, will require an additional laxative to empty stool in the colon

Question 13

Stimulant laxative side effects

Answer 13

• Diarrhoea
• HypOkalaemia (especially when abused)
• Lazy bowel syndrome
• Senna colours urine red-brown

The use of stimulant laxatives should be limited to
2 short treatment courses in 12 years+

Question 14

The use of dantron in stimulant laxatives

Answer 14

Dantron is a stimulant laxative carcinogrenic and genotoxic
It colours urine red and cosues local irrritation. Theerefore only used in palliative care.

Question 15

Stool softener mechanism of action

Answer 15

Reducing surface tension and allows more fluid to enter the stool

Associated with harsher side effects, therefore not routinely recommended

Question 16

Examples of stool softeners

Answer 16

e.g liquid paraffin

Many laxatives already have stool softening properties:

e.g methylcellulose (bulk-forming)
e.g Docusate Sodium (weak stimulant)
e.g Glycerol (rectal stimulant)

Question 17

Stool softener side effects

Answer 17

Harsher side effects:

• Granuloma (small clumps of white blood cells after persistent inflammation)
• Lipoid pneumonia (pools in the lungs and suffocate patient)
• Interferes with the absorption of fat-soluble vitamins: A, D E & K
• Anal seepage and irritation - liquid paraffin may leak from the anus

Question 18

Stimulant laxatives contraindications

Answer 18

CONTRAINDICATED In intestinal obstruction as they will cause colic and severe cramps

Question 19

If the patient is still unresponsive to 2+ laxatives from different classes…

Answer 19

Selective 5-HT4 agonist or Guanylate cyclase-c agonist

• Prucalopride
• Linaclotide (licensed in iBS with constipation)

Question 20

What can be offered in all other laxatives fail in opioid induced constipation?

Answer 20

Peipherally acting opioid-receptor antagonist

Are specifically licensed for opioid-induced constipation when other laxatives fail:
* Methylnaltrexone
* Naloxegol

Question 21

Opiod-induced constipation treatment

Answer 21

Osmotic (or docusate sodium) + stimulant

• Osmotic laxative will draw water and soften hard stools
• Stimulant laxative will increase peristalsis to countract the anti-motility effect of opioids

Bulk-forming laxatives increase the size of stools, so may cause intestinal obstruction or painful colic in opioid-induced constipation, where motility has been slowd

Question 22

Constipation in children treatment

Answer 22

Check for fecal impaction

Macrogol is preferred first line (+ lifestyle measures).
If this is inefficient, add a stimulant laxative
If stools remain hard, add lactulose OR laxative with stool softening properties

Important to manage, to prevent anal fissures which can make defecacting scary :(

e.g
e.g methylcellulose (bulk-forming)
e.g Docusate Sodium (weak stimulant)
e.g Glycerol (rectal stimulant)

Question 23

Constipation in pregnancy and breast-feeding

Answer 23

Bulk-forming laxatives are offered first line (if lifestyle measures fail)

If still no response: glycerol suppositores

AVOID SENNA at term as it can stimulate uterine contractions