2. Constipation Flashcards
Constipation symptoms
- Dry, hard or lumpy stools
- Straining
- Lower abdominal pain or bloating
Constipation red flag symptoms
New onset 50+
Anaemia
Abdominal pain
Weight loss
Blood in stool
Constipation treatent
- 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
Constipation definition
Bowel movements that occur less than 3 times a week
List of laxatives
Bulk-forming
* Ispaghula husk
* Methylcellulose
* Bran
Osmotic
* lactulose
* Macrogol 3550
* Magnesium hydroxide
Stimulant
* Glycerol suppositories
* Senna
* Docusate sodium
* Sodium picosulfate
* Bisacodyl
Bulk-forming laxatives mechanism of action
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
Bulk-forming laxatives side effect
- 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
Osmotic laxative mechanism of action
Drawing water from the body and retain water to soften hard stools and maintain their size
Osmotic laxatives onset of action
Lactulose - starts working in 48 hours
Macrogol - starts working in 2-3 days
Osmotic laxatives side effects
- Diarrhoea, bloating, flatulence, cramps, nausea (common with lactulose)
- Dehydration
Stimulant laxatives mechanism of action
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
Glycerol suppositories onset of action
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
Stimulant laxative side effects
- 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+
The use of dantron in stimulant laxatives
Dantron is a stimulant laxative carcinogrenic and genotoxic
It colours urine red and cosues local irrritation. Theerefore only used in palliative care.
Stool softener mechanism of action
Reducing surface tension and allows more fluid to enter the stool
Associated with harsher side effects, therefore not routinely recommended
Examples of stool softeners
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)
Stool softener side effects
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
Stimulant laxatives contraindications
CONTRAINDICATED In intestinal obstruction as they will cause colic and severe cramps
If the patient is still unresponsive to 2+ laxatives from different classes…
Selective 5-HT4 agonist or Guanylate cyclase-c agonist
- Prucalopride
- Linaclotide (licensed in iBS with constipation)
What can be offered in all other laxatives fail in opioid induced constipation?
Peipherally acting opioid-receptor antagonist
Are specifically licensed for opioid-induced constipation when other laxatives fail:
* Methylnaltrexone
* Naloxegol
Opiod-induced constipation treatment
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
Constipation in children treatment
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)
Constipation in pregnancy and breast-feeding
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
