Constipation Flashcards
How are faeces formed within the large intestine?
Food passes from the small intestine and passes along the caecum colon and into the rectum by peristalsis
What is reabsorbed in the large intestine?
Water and salts reabsorbed which results in excess drying which can cause constipation.
What bacteria is absorbed in the large intestine?
-Ferment non-digestible polysaccharides, some metabolites are absorbed
-Produce Vitamin K and Biotin (Vit B7), which can be absorbed
-Produce gases from undigested polysaccharides
-Essential for development of caecum and lymphatics system
What is the definition of constipation?
The passage of hard stools, less frequently than the patient’s own normal pattern.
Is constipation a symptom or a disease?
SYMPTOM
What features class as difficulty in opening bowels?
-Going less than 3 times a week
-Straining to open bowels more than 25% of occasions
-Hard or pellet-like stool on more than 25% occasions
What is classed as chronic constipation?
More than 12 weeks in the past 6 months. If it occurs 50% of the time this is chronic constipation.
What is the cause of Constipation?
*Age, the very young or very old
*Diet - Low fibre, High animal fat, Inadequate fluid intake, caffeine and alcohol = diuretics causes harder poo
*Poor bowel habits
*Ignoring the urge to defacate
*Imaginary constipation - not eating as much
*IBS
*Intestinal Obstruction
*Pregnancy
*Travel
*Immobility
*Poor thyroid function
What medications cause constipation?
Antacids (Al and Ca salts), Antispasmodics, Antidepressants (Amitriptyline/Doxepin), Iron tablets, Diuretics, Painkillers, Ca channel blockers, ACE inhibitors, Anticholinergic drugs (Hyoscine), Ulcer healing (PPI’s), Antipsychotics (Haloperidol)
Can laxative abuse cause constipation?
YES
What diseases can cause constipation?
*Diabetic autonomic neuropathy
*Spinal cord injury or tumours
*Cerebrovascular accident
*MS
*Parkinsons disease
*Connective tissue disorders
*Hirschsprungs diseases
What is a symptom of constipation in children?
-Infrequent bowel activity, foul smelling wind and stools, excessive flatulence, irregular stool texture, abdo pain distension or discomfort, soiling/overflow.
What is the main cause of constipation in older people?
*decline in GI motility
*Immobility
*Poor diet - low solid and liquid intake
*Wasting of pelvic floor molecules
*Side effects of medicines
=Can get faecal impaction
When constipation is confirmed what are the appropiate steps taken to manage the issue?
-Lifestyle and dietary changes
-Short courses of laxatives
What is an example of ‘Bulking agents’
Ispaghula husk - Fybogel
Methylcellulose
What is an example of a stimulant laxative?
Bisacodyl (oral and rectal)
Senna
Dantron
Sodium pico-sulphate
What is an example of a faecal softeners?
Docusate (Oral and rectal)
Glycerol (Suppository)
Arachis Oil (Enema)
What is an example of Osmotic Laxatives?
Lactulose
Macrogols - Cosmo-col, Movicol, Laxido
Magnesium
Phosphate
Sodium citrate
What is the first line treatment for constipation?
1) Lifestyle advice and to manage the underlying cause.
If a patient is constipated and the first line hasn’t worked, what would then be recommended?
Bulk forming laxative (Ispaghula husk - Fybogel) or Osmotic laxative (Macrogol/Lactulose)
If when constipated, and the first recommended drugs haven’t worked after 1-3 days, what should then be recommended?
Stimulant laxatives - Senna
When does patient need to stop taking laxatives?
Gradually reduce laxatives and stop once the patient has produced a soft, formed stool without straining at least three times per week.
When someone is chronically constipated what may be the final line of treatment?
Prucalopride - this stimulates GI motility
What is the treatment plan if a patient is faecal impacted/loaded with hard stool?
1) High dose oral macrogol (Movicol, Cosmocol, Laxido)
2) Stimulant (Senna)
If response is inadequate or slow, move onto…
3)Glycerol alone or glycerol plus Bisacodyl suppositories
Then…
4)Sodium Phosphate or Arachis oil rentention enema
If a patient is faecally impacted or loaded with soft stool, what should the treatment plan be?
1) Stimulant (Senna/Bisocodyl)
2) Docusate or sodium citrate mini enema
Should patients who have faecal impaction or loading should they be considered for regular laxatives to maintain bowel movements?
YES!
Pt X has Opioid induced constipation, what laxative should be avoided?
Bulk forming laxatives (Ispaghula husk - Fybogel) because the MOA increases faecal mass and Opioids reduce peristalsis.
What is the treatment plan for a patient with Opioid constipation?
1) Osmotic laxatives (Lactulose/Cosmocol/Movicol/Laxido) or docusate and a stimulant laxative (Senna/bisocodyl)
2) Naloxegol
3) Methylnaltrexone
4) Naidemedine
Where does Naloxegol act?
Peripherally acting mu-opioid receptor antagonist (PAMORA), these don’t antagonise the important central opioid receptors.
Where does Methylnaltrexone act?
Peripherally acting mu-opioid receptor antagonist (PAMORA)
*Subcut
Where does Naldemedine act?
Peripherally acting mu-opioid receptor antagonist (PAMORA)
NEW
What lifestyle advice would you offer to someone that is suffering with constipation?
HIGH fibre diet: at least 30g a day.
CAUTION Obstructive symptoms or faecal impaction
-Simple switching from white bread to wholemeal.
How many litres of water would you recommend?
2
What is the first line laxative for a pregnant patient?
1st line - Bulk-forming laxative - Ispaghula Husk (Fybogel)
2nd line - Add or switch to an osmotic laxative (Lactulose/cosmocol/movicol/laxido)
Glycerol suppositories
What laxatives can a pregnant lady not buy OTC and why?
SENNA - pom ONLY and never given close to term as can stimulate labour.
What laxatives are safe for a breastfeeding mother?
1) Offer a bulk-forming laxative (Ispaghula husk - Fybogel)
2) Add or switch to an osmotic laxative (Lactulose/cosmocol/movicol/laxido)
-Can have a short course of a stimulant laxative such as Bisocodyl or Senna.
-Glycerol suppository
What is the treatment plan for children who are constipated?
1) Macrogols AND negotiated and nonpunitive behaviouroal interventions suited to persons stages of development.
2) Add a stimulant laxative (Senna) -do this if 1st line isn’t tolerated!
3) Add lactulose (or docusate) if macrogol is not tolerated
-Continue this at a maintenance dose (could be on this for several months)
What age is Cosmocol paediatric not licensed for?
Children under 2
Are suppositories and enemas recommended for routine use in primary care?
NO
BULK FORMING: What advice should you give for Ispaghula husk Fybogel 3.5/sachet
*Take ONE sachet BD for 12 years+
*Preferably take after meals but not just before bed
*Take 30 mins - 1 hour before or after other medicines
*This remains effects despite if you take it long-term
BULK forming: What advice would you give for someone wanting Methylcellulose (Celevac)?
*500mg tablets
*3-6 tablets BD with at least 300ml of liquid
*Break tablets in the mouth before swallowing
*Do not take just before bed
*Ensure good fluid intake is maintained
*Takes 2-3 days to see an effect
OSMOTIC laxatives & Faecal softeners: What advice do you give to someone taking Macrogol (Movicol/Cosmocol/Laxido)?
*1-3 sachets OD, in divided doses
*Dissolve with 125ml H2O
*Can be high in sodium –> this means they are contraindicated in pt’s with HTN, Heart disease and renal impairment
*Don’t take other oral medicines 1 hour before or after dose
*Different flavours available –> can dilute with squash
*1-3 days for effect
The patient must have adequate fluid intake when on osmotic laxatives T/F?
TRUE
What group of patients are contraindicated with Macrogol laxatives?
*Hypertension, Heart disease, Renal impairment
OSMOTIC/Faecal softeners: What advice would you have for a patient on Lactulose?
*Take 15-25ml OD (single or divided doses)
*Very sweet liquid
*Can cause bloating and colic
*Caution if intolerant to lactose
*This is perfectly fine for diabetic patients as it is not absorbed through the gut
*Take 2 days to have desired effect
OSMOTIC and Faecal softeners: What advice would you have for a patient starting magnesium hydroxide (Milk of magnesia liquid)?
*30-45ml PRN
*Give dose at bedtime
*Can be abused as has a strong effect for weight loss
*Caution for elderly patients
*OTC and can be taken for max 3 days
*Research is weak
*Around 3-6 hours to see desired effect
OSMOTIC and Faecal softeners: What advice would you have for a patient on Docusate?
*Take up to 500mg OD in divided doses
*12-72 hours for effect of tablets
*15 mins for suppositories
*Softening agent and stimulant
*Can be used if a patient finds it difficult to increase their fluid intake
How do you insert a suppository?
1) Lay onto left side, feet level or slightly elevated
2) Use water soluble lubricant and coat blunt end of suppository
3) Insert blunt shape into the anus a finger depth into the anus
4) Lie still and hold inside back passage for 10-15 mins
How do you use an Enema?
1) Warm enema in warm water
2)Hold bottle upright
3)Lie on left hand side, with knees bent up toward your chest
4) Push nozzle in about 7cm into anus
5) Squirt contents into anus and stay laid down
6) try to gold liquid in for 5 minutes
7) Go to toilet when you cannot hold it any longer and stay near a toilet for the next hour.
*Some people get stomach cramps after using an enema
*Some can feel faint or dizzy, if this happens lie down until you feel better
You have a patient who has been prescribed Arachis oil enema, upon questioning you find out they have a peanut allergy, is it safe to give the enema to the patient?
No, Arachis cannot be given to a patient with a peanut allergy.
STIMULANT Laxatives: What advice would you have for a patient on Senna?
*available in tablets and syrup (Syrup is unpalatable)
*7.5-15mg OD, max dose is 30mg OD
*Onset of action 8-12 hours
Where do Stimulant laxatives work?
Smooth muscle of the bowel
What do we have to be aware of if a patient is taking stimulant laxatives long term?
Can cause a lazy bowel, therefore better for short term use
STIMULANT: What advice would you have for a patient on Dantron? (Co-danthramer or co-danthrusate)
*Co-danthramer includes PEG
*Co-danthrusate includes docusate
*Turns urine red
*Avoid prolonged contact with skin
*Only used in terminally ill patients as it is carcinogenic
*not often used
What is the advice for a patient on sodium pico-sulphate?
*5-10mg OD
*Tablets and syrup
*Syrup is palatable
*Onset of action 10-14 hours
STIMULANT: Advice for a patient on Bisocodyl (Duclolax)
*Acts on the small intestine
*5-10mg OD, can be increased if neccessary up to 20mg OD
*Tablets act in 10-12 hours
*Suppositories act in 20-60 mins
*Suppositories can cause local inflammation
Bisocodyl suppositories can cause local inflammation T/F?
True
What class of drug is Prucalopride (Resolor)?
A selective serotonin 5HT4 receptor agonist with prokinetic properties.
What is the max dose of Prucalopride (Resolor)?
2mg OD, if no response after 4 weeks discontinue.
*Reduce dose in the elderly (come in 1mg tablets)
What are the side effects of Prucalopride?
Headaches and GI disturbances
How long does it take for Prucalopride to have an effect?
1-2 weeks
BULK-FORMING MOA:
*Typically, polysaccharides increase osmolality in the gut when broken down, causing water retention.
1) Retention of water in the GIT, so expanding and softening the stool
2) Bulkier stools distend the colon
3) Promotion of peristalsis via stimulating colonic mucosal receptors/stretch receptors causing release of acetylcholine which increases parasympathetic drive.
4) ACh activates muscarinic acetylcholine receptors (M2 and M3), this increases peristalsis and creates a mucus layer in the intestinal lining to facilitate defaecation - 2nd MOA!
OSMOTIC LAXATIVES MOA:
*These are poorly absorbed so act as osmotic agents and increase water retention in the gut lumen
*Hyperosmolar agents, which are absorbed into stool by osmosis to make it softer.
*Many osmotic laxatives have Mg2+ in them to trigger the release of CCK (Cholecystokinin), which increases intestinal secretions and colonic motility, which decreases transit time though the gut
STIMULANT LAXATIVES MOA
Stimulate local reflexes of myenteric nerve plexus of the gut which irritates the nerve endings in the wall of the intestine, this has a motor effect on the gut wall which increases propulsion. this increases secretion of water into the bowel making softer stools an this increases gut motility and decreases transit time.
What is the MOA of Stimulant SENNA:
This is an anthraquinone laxative.
1) It combines with sugars to form glycosides, which attaches to a functional group via a glycosidic bond.
2) The glycosidic bond is hydrolysed by colonic bacteria releasing anthracene glycoside derivatives, speciffically sennosides A and B.
3) This is absorbed and has a direct action on the myenteric nerve plexus, which increases smooth muscle activity
*Also increases PGE2 secretion, which increases gut motility
*Also reduces colonic water absorption - making softer stool which is easier to pass.
STOOL SOFTENERS ‘emollient laxatives’ MOA:
Some work as surface wetting agents/surfactants (Docusate)
*Reduce surface tension which allows water/fats to penetrate stool
-Stool is now softer and easier to pass
What stool softeners create a barrier between stool and the intestinal wall?
Arachis oil and Paraffin
Why isn’t paraffin a popular choice as a stool softener now?
Concerns over carcinogenicity
Prucalopride MOA:
5GT4 receptor agonist
1)5HT4 receptors are in the GI tract (Myenteric plexus)
2) activation of 5HT4 leads to increased release of ACh
3) Increase in rest and digest/parasympathetic drive
4) This increases peristalsis and propulsion
Although there are medications licensed for children who are constipated, initially they should be referred to the GP for a physical examination T/F?
True
What is first line for a child who is constipated?
1) Macrogol - Paediatric dose is POM
What are the red flags for someone who is constipated?
*Pain upon defaecation - suppressing of reflect
*Patient 40+ with sudden change in bowel habits with no ovbious cause
*14 days+ of the issue
*Fatigue
*Repeated failure of laxatives
*Suspected laxative abuse
