Constipation and diarhoea Flashcards
What is constipation
infrequent or difficult evacuation of faecs
Causes of diarrhoea
Incorrect diet habits: low-fibre diet
Diseases: obstructive bowel lesions, IBS
Drug-induced: opiods, anatcids, iron supplements, antidepressants, anticholinergics/antispasmodics
non-drug treatment of constipation
Exercise, incr. bran and fluid intake, discourage continupus use of laxatives
Drug treatment of Constipation
Laxatives–> to accelerate movement of food through GIT
Classes of laxatives
Bulk-forming agents
Osmotic agents
Irritants
Lubricants
Stool softeners
Enemas
Propulsives/Prokinetic agents
Which are the Bulk-forming agents
Ispaghula husk
agar
methylcellulose
Which are the osmotic agents
MgSO4
Mg(OH)2
Lactulose
PEG
Glycerine
Which are the irritants
Castor oil
senns
Bisacodyl
Sodium Picosulphate
Which are the irritants
Castor oil
senna
Bisacodyl
Sodium Picosulphate
Which are the lubricants
Liquid paraffin
Mineral oil
Glycerine
Which are the stool softeners
Docusate sodium
Lactulose
Sorbitol
Which are the Enemas
Isotonic saline solution
soaps
Which are the Propulsives
Linaclotide
Prucalopride
Lubiprostone
MOA of the Bulk-forming agents
(isapaghula husk{psyllium}, Sterculia, Methylcellulose)
indigestible polysaccharides that absorb fluid from GIT–> soft bulky stool formation–> stimulation of bowel action (peristalsis)
Indications of Bulk-forming agnets
Long-term prophylaxis and treatment of Constipation
IBS-C
Diverticular disease
Onset of action of Bulk-forming agents
up to 72hrs
CI of Bulk-forming agents
intestinal obstruction
Stenosis
ulcerations
DI of Bulk-forming agents
decr. absorption of Digoxin
Antidiabetics
Carbamazepine
Lithium
AEs of Bulk-forming agents
Abd. distention
Cramps
Flatulence
What to do when taking Bulk-forming agents + other medications
Medications should be taken 3hrs before or after
Adequate fluid intake is advised to avoid possibility of Intestinal compaction
MOA of Osmotic agents
are poorly absorbed agents that draws water into bowel lumen via osmotic action (incr. osmotic pressure)–> water retention in stools–> incr. stool frequency
I of Osmotic agents
Acute and chronic constipation
Bowel prep
Indications for Lactulose
acute/chronic constipation
Hepatic Encephalopathy
Cautions with Lactulose
Pregnancy+Lactation
CI of Lactulose
Galactosaemia
DI of Lactulose
Warfarin (incr. anticoagulation)
AEs of Lactulose
Flatulence
abd. distention+cramping
I of Polyethylene Glycol (PEG)
acute constipation
Bowel prep
Cautions with Polyethylene Glycol (PEG)
pts>60 yrs
may cause apthpus ulceration
Unconscious patients (ris of regurgitation/aspiration)
CIs of Polyethylene Glycol (PEG)
GI obstruction
Bowel perforation
Toxic megacolon
Onset of action of Polyethylene Glycol (PEG)
24-96 hrs
AEs of Polyethylene Glycol (PEG)
flatulence
abd. distention+cramping
colonic mucosal aphthpus ulceration
Ischarmic colitis
I of Magnesium salts
rapid bowel evacuation
Cautions with Magnesium salts
Hypermagnesaemia
Renal insufficiency
CIs of Magnesium salts
intestinal obstruction/perforation
undiagnosed abd pain
existing electrolyte imbalance
mycocardial damage
AEs of Magnesium salts
electrolyte imbalance- may worsen
abd. cramps
I of Sodium Phosphate
pre-operative
pre-radiography
endoscopic bowel evacuation
Cautions with Sodium Phosphate
risk of phosphate nephropathy
severe dehydration
HF
CIs of Sodium Phosphate
bowel obstruction/perforation
AEs of Sodium Phosphate
electrolyte imbalance
bloating
nausea
abd. pain
MOA of Bisacodyl
direct stimulation of intestinal SM, colonic intramural plexus –> incr. peristalsis; incr. intestinal fluid accumulation and relaxation by altering water+electrolyte secretion
I of Bisacodyl
short-treatment without any pre-existing abdominal issues
Onset of action of Bisacodyl
6-8 hrs orally
15-60mins rectally
DIs of Bisacodyl
Digoxin: decr. serum conc.
CIs of Bisacodyl
intestinal obstruction
undiagnosed abd. pains
AEs of Bisacodyl
abd. cramps
MOA of Senna
direct stimulation of intestinal SM–> incr. GI motility; incr. water+electrlytes accumulation in bowel lumen
onset of action of Senna
6-8hrs
Indications of Senna
acute constipation
bowel prep
DIs of Senna
Digoxin: decr. serum conc.
CIs of Senna
GI obstruction
IBD
AEs of Senna
abd. pain
excessive bowel activity
Hypokalaemia
dehydration
MOA of Sodium Picosulphate
metabolised by colonic bacteria=active metabolite of Bisacodyl–> stimulation of intestinal SM–> incr GI motility–> incr. water+electrolyte accumulation in bowel lumen
Onset of action of Sodium Picosulphate
6-12hrs
Indications of Sodium Picosulphate
severe constipation
bowel prep
CIs of Sodium Picosulphate
GI obstruction
toxic colitis
GI perforation
appendicitis
AEs of Sodium Picosulphate
abd cramps
hypocalaemia
hypokalaemia
MOA of Castor oil
Onset of action of Castor oil
2-6hrs
Is of Castor oil
acute constipation
colonic evacuation
CIs of Castor oil
GI obstruction/perforation
Appendicitis
UC
AEs of Castor oil
Abd. cramps
electrolyte imbalance/disturbance
hypotension
MOA of Lubricant Laxatives
lubricate intestine–> decr. water absorption from colon–> easy passage of stool
I of Lubricant Laxatives
acute constipation
onset of action of Lubricant Laxatives
6-8hrs orally
CIs of Lubricant Laxatives
abd. pain
appendicitis
GI obstruction/perforation
UC
AEs of Lubricant Laxatives
abd cramps
intestinal malabsorption
Lipid pneumonitis
MOA of Stool softeners
(Docusate Sodium- a surfactant lubricant)
Lowers surface tension at faecal oil-water interface–> incr. water absorption by stool–> faecal softening (allows incorpartion of water and fat into stools)
I of Stool softeners
acute/chronic constipation
Onset of action of Stool softeners
24-72hrs
CIs of Stool softeners
abd pain
appendicitis
GI obstruction/perforation
AEs of Stool softeners
abd cramps
excessive bowel activity
Throat irritation
MOA of Linaclotide
is GC agonist
= incr. intracellular cGMP–> stimulates sectretion of Cl and Bicarbonate into GI lumen–> incr. fluid and accelerated transit of GI contents
I of Linaclotide
IBS-C
Chronic idiopathic constipation
CIs of Linaclotide
pts<6yrs (serious risk of dehydration)
GI obstruction
AEs of Linaclotide
Abd. pain
severe diarrhoea
MOA of Prucalopride
selective 5-HT4 Receptor agonist
=illicits GI prokinetic action–> chronic peristalsis–> incr. GI motility
I of Prucalopride
chronic idiopathic construction
CIs of Prucalopride
GI obstruction
IBD
AEs of Prucalopride
abd pain
headache
anxiety
MOA of Lubiprostone
locally acting (on apical portion of intestine) Chloride channel activator= incr. intestinal fluid secretion and motility
I of Lubiprostone
Chronic idiopathic constipation
opiod-induced constipation
IBS-C
CI of Lubiprostone
GI obstruction
IBD
AEs of Lubiprostone
Abd pain
Headache
Anxiety