Abnormal frequent passage of loose stool
Abnormal passage of stools with increased
frequency, fluidity, and weight, or with
increased stool water excretion.
Diarrhea is the condition of having three
or more loose or liquid bowel movements
For adults on a typical Western diet,
stool weight >200 g/d can generally
be considered diarrheal.
Sudden onset in a previously healthy
Lasts from 3 days to 2 weeks
Resolves without sequelae
Lasts for more than 3 weeks
Associated with recurring passage of
diarrheal stools, fever, loss of appetite,
nausea, vomiting, weight loss, and
Diarrhea can be caused by
An increased osmotic load within the intestine
(resulting in retention of water within the lumen)
Excessive secretion of electrolytes and water into
the intestinal lumen.
Exudation of protein and fluid from the mucosa.
Altered intestinal motility resulting in rapid transit
(and decreased fluid absorption).
Pharmacotherapy of diarrhea should be
reserved for patients with significant or
Nonspecific antidiarrheal agents typically do
not address the underlying pathophysiology
responsible for the diarrhea; their principal
utility is to provide symptomatic relief in
mild cases of acute diarrhea.
Mechanism of Action
Coat the walls of the GI tract
Bind to the causative bacteria or toxin,
which is then eliminated through the
Examples: bismuth subsalicylate (Pepto-
Bismol), kaolin-pectin, attapulgite.
Clays such as kaolin (a hydrated aluminum silicate)
and other silicates such as attapulgite (magnesium
aluminum disilicate) bind water avidly and also may
However, this effect is not selective and may involve
other drugs and nutrients; hence, these agents are
best avoided within 2–3 hours of taking other
A mixture of kaolin and pectin (a plant
polysaccharide) is a popular over-the-counter remedy
(kaolin-pectin) and may provide useful symptomatic
relief of mild diarrhea.
Constipation, dark stools
Hearing loss, tinnitus, metallic taste,
Mechanism of Action
Decrease intestinal muscle tone and
peristalsis of GI tract
Result: slowing the movement of fecal
matter through the GI tract
Antimotility and Antisecretory Agents
Opioids continue to be widely used in the treatment of diarrhea.
They act principally through either µ- or δ- opioid receptors on
enteric nerves, epithelial cells, and muscle.
These mechanisms include effects on intestinal motility (µ
receptors), intestinal secretion (δ receptors), or absorption (µ and d
Commonly used antidiarrheals such as Diphenoxylate, and
Loperamide act principally via peripheral µ-opioid receptors and
are preferred over opioids that penetrate the CNS.
Loperamide a Piperidine butyramide derivative with µ-
receptor activity, is an orally active antidiarrheal agent.
The drug is 40–50 times more potent than morphine as an
antidiarrheal agent and penetrates the CNS poorly.
It increases small intestinal and mouth-to-cecum transit
Loperamide also increases anal sphincter tone, an effect
that may be of therapeutic value in some patients who
suffer from anal incontinence.
In addition, loperamide has antisecretory activity against
cholera toxin and some forms of Escherichia coli toxin
Diphenoxylate and Difenoxin
Diphenoxylate and its active metabolite Difenoxin
(diphenoxylic acid) are related structurally to
As antidiarrheal agents, diphenoxylate and difenoxin
are somewhat more potent than morphine.
Both compounds are extensively absorbed after oral
administration, with peak levels achieved within 1–2
Both drugs can produce CNS effects when used in
higher doses (40–60 mg/day) and thus have potential
for abuse and/or addiction.
They are available in preparations containing small
doses of atropine (considered subtherapeutic) to
discourage abuse and deliberate overdosage.
With excessive use or overdose, constipation and (in
inflammatory conditions of the colon) toxic megacolon
In high doses, these drugs cause CNS effects as well
as anticholinergic effects from the atropine (e.g., dry
mouth, blurred vision)
Hydrophilic and poorly fermentable colloids
or polymers such as Carboxymethyl
cellulose and Calcium Polycarbophil
absorb water and increase stool bulk.
They usually are used for constipation but
are sometimes useful in mild chronic
diarrhea in patients suffering with Irritable
Bowel Syndrome (IBS-A).
Antidiarrheal Agents: Interactions
Adsorbents decrease the absorption
of many agents, including digoxin,
clindamycin, quinidine, and
Obtain thorough history of bowel patterns, general
state of health, and recent history of illness or
dietary changes, and assess for allergies
DO NOT give bismuth subsalicylate to children
younger than age 16 or teenagers with chickenpox
because of the risk of Reye’s syndrome.
Anticholinergics should not be
administered to patients with a history
of glaucoma, urinary retention, cardiac
problems, myasthenia gravis.
Difficult, incomplete sensation, or
infrequent evacuation of dry hardened
feces from the bowels
It is symptom, not a disease
Disorder of movement through the colon
Can be caused by a variety of diseases or
Constipation can be corrected by adherence to a fiber-
rich (20–30 g daily) diet, adequate fluid intake,
appropriate bowel habits and training, and avoidance
of constipating drugs.
Constipation related to medications can be corrected
by use of alternative drugs where possible, or
adjustment of dosage.
If nonpharmacological measures alone are
inadequate, they may be supplemented with bulk-
forming agents or osmotic laxatives.
When stimulant laxatives are used, they
should be administered at the lowest
effective dosage and for the shortest period
of time to avoid abuse.
Habitual use of laxatives may lead to
excessive loss of water and electrolytes;
secondary aldosteronism may occur if
volume depletion is prominent.
The terms laxatives, cathartics, purgatives, and
evacuants often are used inter changeably.
There is a distinction, however, between laxation (the
evacuation of formed fecal material from the rectum)
and catharsis (the evacuation of unformed, usually
watery fecal material from the entire colon).
Laxatives are employed before surgical, radiological,
and endoscopic procedures where an empty colon is
1)Bulk laxatives: by increasing the
volume of non-absorbable solid residues
Eg: Hydrophilic Colloids, Bran, Methylcellulose,
2)Osmotic laxative: by increasing the
Eg: Saline purgatives:MgSo4 (Epsom salts),
Mg(OH)2 (MOM), Lactulose
3)Fecal Softners: by altering the
consistency of feces
Eg: DOSS (dioctyl sodium sulfosuccinate), Mineral
oils, Glycerin suppositories
by increasing the motility and secretion
Eg: Senna, Cascara, Castor oil, Bisacodyl.
Include hydrophilic colloids(prepared from indigestible
parts of fruits, vegetables and seeds)
Forms gel in large intestinecause water retention and
intestinal distension increase peristaltic activity
Are first line approach for most pts of simple constipation
Habitual constipation in elderly pts
Saline purgatives: Laxatives containing magnesium
cations or phosphate anions commonly are called saline
laxatives: magnesium sulfate, magnesium hydroxide,
magnesium citrate,sodium phosphate
Solutes that are not absorbed in intestineretain more
water osmoticallydistend the bowelincrease
peristalsisleads purgation about an hour later
Abd. cramps can occur
Quick onset of action
Advised to take plenty of water
administration of hypertonic sol may cause
For preparation of bowel before surgery
In food/drug poisoning
Semisynthetic disaccharide of fructose and
galactosenot digested or absorbed in small
In colonbacteria convert it into two component
sugarfermentationlactic acid and acetic
acidfunction as osmotic laxative
After lactulose administration, gut contents have low
pH than normaldecrease activity of ammonia
producing organismhence used in treatment of
Promote more water and fat in the stools
Lubricate the fecal material and intestinal walls
Emulsifying effect on fecesmake them retain more
watersofter stooleasier to pass out
Abd cramps can occur
Uses: condition where straining at stool has to be
avoided like hernia, piles, fissures, anal surgery
They increase the peristalsis by stimulation
of gut mucosa
Causes abd cramps, prolonged use cause
atonic colon(sluggish bowel)
Used mainly for preparation of bowel for
surgery, colonoscopy and abd X-rays
Bisacodyl: given orally and also as
suppositorydefecation in 15-30min
Phenolphthalein: given orally
A/E:allergic rashes in skin
Laxatives: Nursing Implications
Assess fluid and electrolytes before
Patients should not take a laxative if they are
experiencing nausea, vomiting.
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
Abuse and danger of laxative
Repeated administration may produce:
GI disturbaces like spastic colitis, dyspepsia, anorexia
Nutritional deficiencies of calories, vitamins, minerals
Loss of fluids and electrolytes
Complete dependency on drugs