Constipation Flashcards
What are the cautions of constipation?
- Inadequate fibre:
Fibre adds bulks to stools and improves bowel function. Fibre includes fruit, vegetables, cereals and whole bread. - Medications:
Such as painkillers like codeine and morphine, some antacids (aluminium), some antidepressants, and iron tablets. - Medical conditions:
Such as IBS, underactive thyroid and some bowel disorders. - Pregnancy: Due to hormonal change, bowel movements are slowed.
What are red flags for constipation?
- New onset of constipation when 50 years and over.
- Anaemia
- Abdo pain
- Unexplained weight loss
- Blood in stool (black & mixed in stool - could mean cancer or G.I bleed)
What are the different types of Laxatives?
BOSS
B - Bulk
O - Osmotic
S - Stimulant
S - Softeners
& Linaclotide & Prucalopride (5-HT4 receptor agonist)
What are examples of Bulk laxatives?
- Bran
- Ispaghula husk
- Sterculia
- Methyl cellulose
What are examples of osmotic laxatives?
- Macrogols (laxido)
- Lactulose
- Magnesium salts (MgO)
What are examples of Stimulants laxatives?
- Bisacodyl
- Senna
- Sodium picosulfate
- Glycerol
- Co-danthramer
- Docusate sodium (stimulant & softner)
What are examples of softeners laxatives?
- Liquid paraffin
- Docusate sodium (stimulant & softner)
- Arachis (peanut) enemas (also lubricates faeces)
What do Bulk forming laxatives do and when is it normally used?
It increases bulk in the stool like fibre does. and has an onset action up to 72 hours.
Used in:
- colostomy
- ileostomy
- haemorrhoids
- anal fissure
- IBS
- Diverticular disease
- Ulcerative colitis
What should patients do when taking bulk forming laxatives and why?
Maintain adequate fluid intake to prevent intestinal obstruction.
What can be a side effect of bulk forming laxatives?
- Bloating
- Cramping
- Flatulence
What do stimulant laxatives do and what is their onset time?
Increases intestinal motility.
Onset is 8-12hrs, therefore bedtime dose is recommended.
But stimulant laxative suppositories act quicker within 20-60 mins.
What are the side effects of stimulant laxatives?
- Abdominal cramps
And there is an abuse risk which can also cause hypokalaemia.
When should stimulant laxatives be avoided?
Avoid in intestinal obstruction.
Which stimulant laxatives are only reserved for terminally ill patients?
Co-danthramer & Co-danthrusate
What is the MHRA updates for stimulant laxatives?
Pack size restrictions:
- Products available for general sale is limited to a pack size of two short treatment courses (up to 20 standard-strength tablets, 10 maximum-strength tablets or 100ml solution/syrup.
Recommended ages:
- Recommended for use in people 18 years and older. No longer used in children under 12 years without advice from prescriber.
Products for ages 12-17 years can be supplied under supervision of a pharmacist.
If used regularly for long-term use in chronic constipation or inappropriate for self-care (such as for bowel clearance before surgery), should only be given on prescription only products.
What do faecal softeners do?
They decrease surface tension and increase penetration of liquid into faecal mass
What is a side effect of liquid paraffin?
Can cause malabsorption of fat soluble vitamins
What do osmotic laxatives do?
Increase the amount of water in large bowel by drawing fluid from the body into bowel or maintaining fluid in the bowel.
Which osmotic laxative acts faster?
Macrogols
Lactulose takes up to 2 days for max effect - not suitable for immediate relief.
What is the side effect of lactulose?
- Abdo pain
- Bloating
- Electrolyte imbalance
What condition is lactulose normally used for?
Hepatic encephalopathy
Which laxatives clear the bowel quickly?
- Phosphate enemas (saline laxatives)
- Magnesium salts (osmotic laxatives)
What can laxative abuse lead to?
Hypokalaemia
Which drugs cause constipation?
VEry Old Antis get Constipations
Verapamil
Opiates
Antimuscarinics
Antihistamines
Anti-epileptics
Antispasmodics
Antipsychotics
Antidepressants
Antacids (aluminium)
What is the order in which laxatives are used?
Bulk forming laxatives are normally used first.
Then osmotic
Then stimulant if others are ineffective.
(BOS - Bulk, osmotic, then stimulant)
Use one at a time, not together.
Explain the management of constipation in different conditions?
- Short duration constipation (BOS)
-Pregnancy/Breastfeeding (BOS)
- Chronic constipation (BOS)
^ SPC is BOS ^
- Faecal impaction (OS)
- Children (OS) o = macrogol
- Opioid induced constipation (OS / Naloxegol/methylnaltrexone)
What is the patient and carer advice for bulk forming laxative?
Preparations that cause swelling when in contact with liquid, should be carefully swallowed with water and should not be taken immediately before going to bed. The full effect may take a few days to develop.
So takes hours before going to bed and drink A LOT of water.
