Laxatives Treatment Summary Flashcards
When should constipation provoke urgent investigation?
New onset constipation in:
- patients over 50 years of age, or
accompanying symptoms such as:
- anaemia,
- abdominal pain,
- weight loss, or
- overt or occult blood in the stool
Urgent investigation because of the risk of malignancy or other serious bowel disorder.
General constipation advice?
- increase fibre slowly to avoid bloating (grains, fruit veg)
- adequate fluid
- fruit with fibre and sorbitol
Laxative abuse may lead to hypokalaemia.
What are the main types of laxatives?
- Bulk-forming
- Stimulant
- Faecal softeners
- Osmotic
- Others
Tell me about bulk forming laxatives?
- bran, ispaghula husk, methylcellulose, sterculia
- small hard stool in adults who cannot increase dietary fibre
- onset 72hrs
- Sx of flatulence, bloating and cramping may be exacerbated
- adequate fluid intake
- AVOID in intestinal obstruction
(methylcellulose is also a softener)
Tell me about stimulant laxatives?
- BISACODYL, sodium picosulfate
- anthroquinones: SENNA, co-danthramer, co-danthrusate
- increase motility, cramps
- avoid in intestinal obstruction
- glycerol suppositories are lubricant and rectal stimulant as mildly irritant
(danthramer ones are carcinogenic so only in terminally ill)
- docussate sodium is stimulant and softener)
Tell me about faecal softeners?
- decrease surface tension and increase penetrance of fluid
Suppositories: - DOCUSSATE SODIUM (also stimulant)
- GLYCEROL (also stimulant)
- arachis oil enemas
- liquid paraffin (adverse effects)
Tell me about osmotic laxatives?
- increase water in large bowel by keeping it or drawing it in
- LACTULOSE (not absorbed by GI)
- gives osmotic diarrhoea of low pH, decreases ammonia bacteria -> useful in hepatic encephalopathy
- MACROGOLS, draw fluid in, could prescribe with fluids to reduce dehydration
What are some Other drugs used in constipation?
Linaclotide
- guanylate cycling-C receptor agonist
- moderate to severe IBS constipation
Prucalopride
- selective 5HT4 receptor agonist with prokinetic properties
- chronic constipation in adults when other drugs laxatives have failed
What would you do for short duration constipation where dietary measures are ineffective?
- start with bulk-forming laxative, ensure adequate fluid
remain hard:
- add or switch to osmotic
soft but difficult to pass / inadequate empty:
- add a stimulant laxative
What do you do in opioid induced constipation?
- osmotic laxative and a stimulant laxative
- avoid bulk-forming laxatives
- naloxegol when response to other laxatives is inadequate
- methynaltrexone bromide when response to others is inadequate or as adjunct in palliative care
What do you do in faecal impaction?
Hard stools:
- high dose oral MACROGOL
Those with soft stool or still hard after macrogol:
- oral stimulant
Still inadequate response to orals:
- soft stool give bisacodyl (stimulant)
- hard stool give glycerol (softener)
more enemas: decussate sodium, arachis oil etc.
What do you do in chronic constipation?
Start:
- bulk-forming and hydration
Then:
- add / change to osmotic eg macrogol or lactulose
Want one or two soft stools a day
Tried at least two classes at max dose for 6 months?
- women try PRUCALOPRIDE for 4 weeks
Slowly withdraw laxatives, stop stimulants first if they are on them, may need to increase others.
Constipation in pregnancy?
Lifestyle and dietary, fibre
Bulk-forming laxative if that fails
Osmotic eg lactulose
Bisacodyl or Senna stimulants but not Senna near term
Docusate sodium or glycerol suppositories
