Transcript Laxatives: use

*
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2005, 2002 by Mosby, Inc.
*Abnormally
infrequent and difficult passage of
feces through the lower GI tract
*Symptom, not a disease
*Disorder of movement through the colon
and/or rectum
*Can be caused by a variety of diseases
or drugs
*
.
* Constipation
is generally defined as infrequent and/or
unsatisfactory defecation fewer than 3 times per week.
* Patients may define
constipation as passing hard stools or
straining, incomplete or painful defecation.
*
Epidemiology
2-27% of the population has constipation
Constipation affects twice as many women as
men
Constipation is more prevalent in non-White
persons than in White persons (nonWhite:White ratio range 1.11--2.89)
Causes of constipation
 Diet
 Lack of exercise
 Age
 Irregular bowel habits
 Drug induced
 Disease States/Conditions
Spasam of sigmoid colon
Dysfunction of myenteric plexus
I’m constipated, now what?
Two approaches to consider:
 Non-drug Approach
 Drug Approach
No evidence that increased exercise is beneficial in
severe constipation
Aim for 25-30g fibre/day
Unless dehydrated, increasing fluid does not relieve
chronic constipation and may increase the risk of fluid
overload eg heart or renal failure
* 1. Exercise - Fibre in the diet Fluid Intake
*Bulk forming
*Emollient
*Hyperosmotic
*Saline
*Stimulant
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1. Bulk forming
*High fiber
*Absorbs water to increase bulk
*Distends bowel to initiate reflex bowel activity
Examples:
*psyllium (Metamucil)
*methylcellulose (Citrucel)
*polycarbophil
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Improve stool consistency and frequency with regular
use
Ensure good fluid intake to prevent faecal
impaction
Onset of action 2-3 days
Side Effects may include bloating, flatulence,
distension
2. Emollient
*Stool softeners and lubricants
*Promote more water and fat in the stools
*Lubricate the fecal material and intestinal
walls
Examples:
*Stool softeners: docusate salts (Colace, Surfak)
*Lubricants: mineral oil
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*Stool
softener
effective.
may
take
days
to
become
*They
should not be taken together with mineral
oil because of the potential for absorption of the
mineral oil.
*Lubricant
laxatives include Mineral oil and
glycerin suppositories.
* They facilitate the passage of hard stools.
*Mineral oil should be taken orally in an upright
position to avoid its aspiration and potential for
lipid or lipoid pneumonia.
3. Hyperosmotic
*Increase fecal water content
*Result: bowel distention, increased peristalsis,
and evacuation
Examples:
*polyethylene glycol (GoLYTELY)
*sorbitol
*glycerin
*lactulose (Chronulac)
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*PEG
powder for solution is available as a
prescription and also an over-the-counter
laxative.
*Lactulose
is a semisynthetic disaccharide sugar
that also acts as an osmotic laxative. It is a
product that cannot be hydrolyzed by intestinal
enzymes. Oral doses are degraded in the colon
by colonic bacteria into lactic, formic, and
acetic acids. This increases osmotic pressure,
thereby accumulating fluid, distending the
colon, creating a soft stool, and causing
defecation.
Saline
*Increase osmotic pressure within the intestinal
tract, causing more water to enter the
intestines
*Result: bowel distention, increased peristalsis,
and evacuation
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Saline laxative; saline cathartic; examples:
*magnesium sulfate (Epsom salts)
*magnesium hydroxide (MOM)
*magnesium citrate
*sodium phosphate (Fleet Phospho-Soda, Fleet
enema)
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*Saline
cathartics are nonabsorbable salts
(anions and cations) that hold water in the
intestine by osmosis and distend the bowel.
*increasing
intestinal activity and producing
defecation in a few hours.
*Electrolyte
solutions containing polyethylene
glycol (PEG) are used as colonic lavage solutions
to prepare the gut for radiologic or endoscopic
procedures.
4. Stimulant
*Increases peristalsis
stimulation
Examples:
*castor oil
*senna
*cascara
*bisacodyl
via
intestinal
nerve
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*Senna is a widely used stimulant laxative.
* Its active ingredient is a group of sennosides,
a natural complex of anthraquinone glycosides.
*Taken
orally, it causes evacuation of the
bowels within 8 to 10 hours.
*It
also causes water and electrolyte secretion
into the bowel.
*In
combination products with a docusatecontaining stool softener, it is useful in treating
opioid-induced constipation.
*Bisacodyl,
available as suppositories and entericcoated tablets, is a potent stimulant of the colon.
*It acts directly on nerve fibers in the mucosa of the
colon.
*Adverse
effects include abdominal cramps and the
potential for atonic colon with prolonged use.
*.
*Antacids should not be taken at the same
time as the enteric-coated tablets. The
antacid would cause the enteric coating
to dissolve prematurely in the stomach,
resulting in stomach irritation and pain.
*The
same adverse effects could be
expected
with
milk,
H2-receptor
antagonists, and PPIs
*Castor
oil is broken down in the small
intestine to ricinoleic acid, which is very
irritating to the gut, and promptly increases
peristalsis.
*It
should be avoided by pregnant patients,
because
it
may
stimulate
uterine
contractions.
*Bulk forming
*Impaction
*Fluid overload
*Emollient
*Skin rashes
*Decreased absorption of vitamins
*Hyperosmotic
*Abdominal bloating
*Rectal irritation
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*
*
Saline
*Magnesium toxicity (with renal insufficiency)
*Cramping
*Diarrhea
*Increased thirst
Stimulant
*Nutrient malabsorption
*Skin rashes
*Gastric irritation
*Rectal irritation
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*All
laxatives
imbalances!
can
cause
electrolyte
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2005, 2002 by Mosby, Inc.
*Obtain
a thorough history of presenting
symptoms,
elimination
patterns,
and
allergies
*Assess fluid and electrolytes before
initiating therapy
*Patients should not take a laxative or
cathartic if they are experiencing nausea,
vomiting, and/or abdominal pain
*
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*A
healthy, high-fiber diet and increased
fluid intake should be encouraged as an
alternative to laxative use
*Long-term
use of laxatives often results in
decreased bowel tone and may lead to
dependency
*All
laxative tablets should be swallowed
whole, not crushed or chewed, especially
if enteric coated
*
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2005, 2002 by Mosby, Inc.
*Patients should take all laxative tablets with
6 to 8 ounces of water
*Patients should take bulk-forming laxatives
as directed by the manufacturer with at least
240 mL
(8 ounces) of water
*
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2005, 2002 by Mosby, Inc.
*Bisacodyl
and cascara sagrada should be
given with water due to interactions with
milk, antacids, and H2 blockers
*
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2005, 2002 by Mosby, Inc.
*Patients
should
contact
their
physician if they experience severe
abdominal pain, muscle weakness,
cramps, and/or dizziness, which may
indicate possible fluid or electrolyte
loss
*Monitor for therapeutic effect
*
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2005, 2002 by Mosby, Inc.