laxatives Flashcards
name the key laxative
senna
used to treat what?
constipation (orally)
as suppositories for faecal impaction (rectally)
MOA
increases water and electrolyte secretion from the colonic mucosa
increase content of colon and volumne which stimulates perstialsis and therefore movement
disadvantage of suppositories
localised effect to rectal region
side effects
abdominal pain or cramping
diarrhoea
prolonged use can cause what ?
melanonsis coli - reversible pigment of intestinal wall
contraindications what may it induce
patients with intestinal obstruction may induce perforation
anal fissures and haemorrhoids
what should be avoided in these patients
rectal preparations
drug reactions
none clinically significant
patient information for constipation
drinking plenty
fibre intake
need only afew doses before results are seen
dose can be adjusted
cramps and flatulence are normal - likely to get better over time
what are the other laxatives ?
isphagula husk
lactulose
macrogol
phosplate enemas
what is isphagula husk used for
constipation and faecal impaction where fibre cannot be increased
mild chronic diarrhoea associated with IBD/diverticular disease
MOA
hydrophilic substance such as cellulose which cannot be absorbed or broken down
this attracts water into the stool and increases it mass
adequate fluid is therefore essential
increasing stool bulk -> peristalsis and aids relief of constipation
adverse events
well tolerated - may cause abdominal distention
flatulence
GI obstruction -rarely
warning/contraindications
not in patients with intestinal obstruction
faecal impaction
drug interactions
no clinically significant adverse drug interactions
PI
lots of water
acts as fibre supplement
dose can be adjusted
indication of lactulose and macrogol
constipation
bowel prep prior to surgery/endoscopy
HE
MOA
osmotically active substance
not digestions or absorbed and remain in gut lumen
hold water ijn the stool
stimulates peristalsis
MOA in HE
reduces ammonia absorption by increasing gut transit rate
SE of lactulose
cramping
farting
nausea
diarrhoea electrolyte disturbances
warning
contraindicated in obstruction - risk of perforation
in caution with Heart failure and ascitres
drug interactions
may increase warfarin effects
doses
15ml x2 daily but 30-50ml in HE 3x a day
enema once daily
which of the three causes nausea?
lactulose
which should not be used in heart failure?
lactulose
outline difference between 3
[1] increase in water and eleclytoe secretions from colonic musoca
[2] relies on non-digestable bulk- draws water in
(£) osmotlyitcal active substance not digested drawing water in
which can be used for bowel prep?
lactulose
which can cause melaonosis coli
senna
which replaces fibre?
isphagula husk
