Gastrointestinal Tract-Constipation Flashcards
What is constipation?
Hard stools- lower frequency than patient’s normal bowel habits.
When to avoid laxatives?
If 2ndary causes of constipation such as HYPOthyroidism, IBS C or other bowel conditions.
When are laxatives useful?
-Before surgery or procedure e.g. colonoscopy
-Drug-induced constipation e.g. antidepressants, opioids, aluminium antacids and iron tablets.
-Antithelmatic treatment for threadworms to get rid of worms.
-If excessive straining can exacerbate e.g. angina or lead to rectal bleeding with haemorrhoids.
What can excessive laxative usage cause?
Hypokalaemia
Types of laxatives?
BOSS
Bulk-forming: Sterculia, methylcellulose, isphagula husk and bran
Osmotic laxatives: Lactulose and Laxido
Stimulant laxatives: Bisacodyl and senna
Softeners: Linaclotide and Prucalopride
Constipation <1 years of infants
1- Increase fluids or fruit juices with sorbitol e.g. apple, pear
2-Osmotic laxatives e.g. lactulose
3-If faecal impaction–> Macrogol or rarely glycerol suppo.
4-Not effective-refer
Constipation>1 without impaction
1-diet modification: increase fibre and fluids
2- Osmotic laxatives with macrogol
3-If can’t tolerate macrogol–> just lactulose
4- Stimulant laxatives if ineffective.
Constipation>1 with foecal impaction
1- Macrogol
2-Ineffective after 2w–> stimulant
3-Ineffective after 2w–> sodium citrate enemas
4-Ineffective after 2w–> refer to specialist for phosphate enemas
Advice to parents about constipation in children?
-Some children may need to continue laxatives for weeks or even months until they establish healthy bowel movements and toilet training.
-Adjust the dose of laxative depending on the bowel movements.
-Gradually reduce the dose of laxative once the patient has established healthy bowel movements.
Constipation in pregnancy?
1st line- diet and lifestyle modifications
2nd line- moderate dose of poorly absorbed laxatives e.g. lactulose
3rd line- if stimulation required- bisacodyl and senna
Bulk-forming laxatives? Their function? Any S/E? Patient advice?
include; methylcellulose, bran, isphagula husk and sterculia.
Take around 2-3 days (72 hours to work)
Can cause abdominal distention and flatulence.
MOA: increase foecal mass and induce peristalsis.
Patient advice: avoid taking at bedtime and maintain adequate hydration to avoid intestinal obstruction.
Stimulant Laxatives? Onset of action? MOA? any S/E? Patient advice?
Examples: senna, bisacodyl, glycerol, docusate sodium, sodium picosulfate, con-danthramer and co-danthrusate
Co-danthramer and danthrusate: only for terminally ill patients are carcinogenic and discolour urine red.
Take 6-12 hours to work but suppositories and enemas take 15-50 minutes to work.
They stimulate colonic nerve to increase pesistalsis, docusate sodium also has softener properties.
Can cause abdominal cramps and abdominal pain.
Patient advice: take at bedtime
Stimulant laxatives MHRA warning and change in licensing?
Pack size is limited:
-Standard tablet dose: max 20 tablets
-Maximum dose: max 10 tablets
-Fluid: max 100 ml
Age limit:
-GSL >18
-P medication> including 12
-No longer first line treatment.
1st: diet modification
2nd: Bulk 3rd: osmotic and 4th is stimulant
If <12 refer -Treatment is lifestyle modification, CBT and macrogol.
Osmotic Laxatives MOA? S/E? Indications? Onset of Action?
Examples include lactulose and macragol (laxido and movicol).
Maximum effect in 2 days but macragol generally acts faster. They increase penetration of water through osmosis into large intestine softening the stool.
Lactulose can also be used in hepatic encephalopathy as well.
Can lead to electrolyte disturbances, abdominal cramps, bloating and flatulence.
Doses of Lactulose?
1-11 months- 2.5ml twice daily
1 year- 4 years- 2.5ml-5ml twice daily
5 years-17 years- 5ml-10ml twice daily
Adults-15 ml twice daily
HEpatic encephalopathy- 30ml-50 ml three times a day adjusted according to response or to 2-3 stools per day.
