This document provides information on diarrhoea and constipation. It defines diarrhoea as having 3 or more loose stools per day. The causes of diarrhoea include infection, inflammation, malabsorption and disorders of gut motility. Management involves treatment of dehydration with oral rehydration solutions and intravenous fluids, followed by treatment of the underlying cause. Laxatives are used to treat constipation and are classified based on their mechanism of action into bulk forming, stool softeners, stimulant and osmotic types.

1. Diarrhoea
According to WHO Diarrhoea is a
condition having 3 or more loose stools
per day.
In pathological terms, it occurs due to passage
of excess water in faeces. This may be due to:
•Decreased electrolyte and water absorption.
•Increased secretion by intestinal mucosa.
•Increased luminal osmotic load.
•Inflammation of mucosa and exudation into
lumen.

2. Diarrhoea
 There is imbalance
between secretion and
reabsorption of fluid
and electrolytes.
 Treatment is aimed at
restoration of fluid
and electrolyte
balance first.
 Then treatment of the
cause.

3. Causes of Diarrhoea:
1. Infection with enteric organism
2. Inflammatory bowel disease
3. Malabsorption due to disease
4. Disorder of gut motility
5. Secretory tumors – rare

4. Classification
Osmotic diarrhoea
Something in the bowel is drawing water from the body into the
bowel.
Eg; Sorbitol is not absorbed by the body but draws water from the
body into the bowel, resulting in diarrhoea.
Secretory diarrhoea
Occurs when the body is releasing water into the bowel, many
infections, drugs causes secretory diarrhoea.
Exudative diarrhoea
Diarrhoea with the presence of blood and pus in the stool. This occurs
with inflammatory bowels disease (IBD), such as crohn’s disease or
ulcerative colitis etc.

5. Acute diarrhoea
Sudden onset in a previously healthy person
Lasts from 3 days to 2 weeks
Self-limiting
Resolves without sequelae
Chronic diarrhoea
Lasts for more than 3 weeks.
Associated with recurring passage of diarrhoeal stools, fever,
loss of appetite, nausea, vomiting, weight loss, and chronic
weakness

6. CAUSES OF DIARRHOEA
Acute Diarrhoea
Bacterial
Viral
Drug induced
Nutritional
Protozoal
Chronic Diarrhoea
Tumours
Diabetes
Addison’s disease
Hyperthyroidism
Irritable bowel syndrome
E. Coli bacteria Rotavirus

7. Principles of management
(a) Treatment of fluid depletion, shock and
acidosis
• ORS, IV Fluids
• Zinc supplement
(b) Maintenance of nutrition
(c) Drug therapy
• Specific antimicrobial drugs
• Probiotics
• Drugs for Inflammatory Bowel Disease
• Nonspecific antidiarrhoeal drugs

8. The goal in managing dehydration caused
by diarrhoea is to correct existing deficits of
fluid and electrolytes rapidly and then to
replace further losses as they occur until
diarrhoea stops.
IV Rehydration
Oral Rehydration
Supplementary zinc benefits children with
diarrhoea because it is a vital micronutrient
essential for protein synthesis, cell growth
and differentiation, immune function, and
intestinal transport of water and
electrolytes.

9. Rehydration Therapy

11.  Ringers lactate solution ( hartmans solution)
 It supplies adequate concentration of sodium
and lactate which is metabolized to
bicarbonate for the correction of base deficit
acidosis.
 Dextrose injections
 Source of calories & water for hydration.
 Sodium chloride injections (Normal saline)
 Normal saline has same osmotic pressure as
body fluids.
 Source of sodium chloride & water for injection.

12.  Dextrose Normal Saline (DNS)
 1:1 mixture of isotonic sodium chloride & 5%
glucose allow water to enter body cell &
sodium salt remains extracellular.
 Plasma expanders
• Human albumin
• Dextran
• Degraded gelatin polymer
 Exerts colloidal osmotic pressure & retained in
intravascular compartment.
 Substitute for plasma

13.  Dhaka Fluid
 The recommended composition of i.v. Dhaka
fluid is:
 NaCl 85 mM = 5 g
 KCl 13 mM = 1 g
 NaHCO3 48 mM = 4 g
 This provides 133 mM Na+, 13 mM K+, 98 mM
Cl¯ and 48 mM HCO3 ¯. Ringer lactate (Na+
130, Cl¯ 109, K+ 4, lactate 28 mM)
recommended by WHO (1991).
 Volume equivalent to 10% BW should be
infused over 2–4 hours; the subsequent rate of
infusion is matched with the rate of fluid loss.
 In most cases, oral rehydration can be
instituted after the initial volume replacement.

14. Antidiarrhoeal drugs
1. Specific antimicrobial drugs
2. Probiotics
3. Drugs for inflammaory bowel disease (IBD)
4. Nonspecific antidiarrhoeal drugs.
a)Absorbents: Ispaghula, methylcellulose
b)Adsobents: Kaolin, pectin
c)Antisecretory: Bismuth subsalicylate,
Octreotide, Racecadotril
d)Antimotility: Loperamide, Diphenoxylate

15. Antimotility drugs
 MOA
 They increase colonic phasic segmenting
activity through inhibition of presynaptic
cholinergic nerves in the submucosal and
myenteric plexuses and lead to increased
colonic transit time and fecal water
absorption.
 They also decrease mass colonic
movements and the gastrocolic reflex.

16. Loperamide is a nonprescription
opioid agonist
 It does not cross the blood-brain barrier and
has no analgesic properties or potential for
addiction
 Tolerance to long-term use has not been
reported
 It is typically administered in doses of 2 mg
taken one to four times daily

17. Diphenoxylate is another opioid
agonist
 Has no analgesic properties in standard
doses
 Higher doses have CNS effects
 Prolonged use can lead to opioid
dependence
 Commercial preparations commonly contain
small amounts of atropine to discourage
overdosage (2.5 mg diphenoxylate with
0.025 mg atropine)
 The anticholinergic properties of atropine
may contribute to the antidiarrheal action.

18. KAOLIN & PECTIN
 Kaolin is a naturally occurring
hydrated magnesium aluminum silicate
(attapulgite)
 Pectin is an indigestible carbohydrate
derived from apples
 Both appear to act as absorbents of
bacteria, toxins, and fluid, thereby
decreasing stool liquidity and number
 They may be useful in acute diarrhea
but are seldom used on a chronic basis

19. KAOLIN & PECTIN
 A common commercial preparation is
Kaopectate
 The usual dose is 1.2-1.5 g after each loose
bowel movement (maximum: 9 g/d)
 Kaolin-pectin formulations are not
absorbed and have no significant
adverse effects except constipation
 They should not be taken within 2 hours of
other medications (which they may bind)

20.  Antimicrobials are of no value In diarrhoea due
to noninfective causes, such as:
(i) Irritable bowel syndrome (IBS)
(ii) Coeliac disease
(iii) Pancreatic enzyme deficiency
(iv) Tropical sprue
(v) Thyrotoxicosis

21. Antimicrobials are useful only in severe disease:
(i) Travellers’ diarrhoea: mostly due to ETEC,
Campylobacter or virus: cotrimoxazole, norfloxacin,
doxycycline reduce the duration of diarrhoea and total
fluid needed only in severe cases.
(ii) EPEC: is less common, but causes Shigellalike invasive
illness. Cotrimoxazole, or a fluoroquinolone or colistin may
be used in acute cases and in infants.
(iii) Shigella enteritis: only when associated with blood and
mucus in stools may be treated with ciprofloxacin or
norfloxacin.
(iv)Nontyphoid Salmonella enteritis is often invasive; severe
cases may be treated with a fluoroquinolone,
cotrimoxazole or ampicillin.
(v) Yersinia enterocolitica: common in colder places, not in
tropics. Cotrimoxazole is the most suitable drug in severe
cases; ciprofloxacin is an alternative.

22.  Antimicrobials are regularly useful in:
(i) Cholera: Tetracyclines reduce stool volume to nearly
half. Cotrimoxazole is an alternative, especially in
children. Multidrug resistant cholera strains can be
treated with norfloxacin/ciprofloxacin. Ampicillin and
erythromycin are also effective.
(ii) Campylobacter jejuni: Norfloxacin and other
fluoroquinolones eradicate the organism from the stools
and control diarrhoea. Erythromycin is fairly effective
and is the preferred drug in children.
(iii) Clostridium difficile: The drug of choice for this
superinfection is metronidazole, while vancomycin given
orally is an alternative.
(iv)Diarrhoea associated with bacterial growth in blind
loops/diverticulitis may be treated with tetracycline or
metronidazole.
(v) Amoebiasis metronidazole, diloxanide furoate
(vi) Giardiasis metronidazole, diloxanide furoate

23. Probiotics
 Help to get back in tracks
 Recolonization of the gut by non pathogenic
mostly lactic acid bacteria and yeast
believed to restore balance.
 Lactobacillus rhamnosus, lactobacillus reutei,
saccharomyces boulardii are the strains
effective
 Natural curd/yogurt is an abundant source of
lactic acid producing organisms, which can
serve as probiotic. For all practical purposes,
probiotics are safe.

24. Drugs for inflammaory bowel disease
(IBD)
The drugs used in UC and CrD are the
same, but their roles and efficacy do
differ. Drugs used in IBD can be grouped
into:
• 5-Amino salicylic acid (5-ASA)
compounds
•Corticosteroids
• Immunosuppressants
• TNFα inhibitors

25. CONSTIPATION
• Constipation is a condition where there is
infrequent bowel movement, usually less than 3
stools per week.
• As the food moves down through the large
intestine, the colon absorbs water while forming
waste products or stool. Muscle contraction in
the colon push the stool towards rectum. By the
time the stool reaches rectum it is solid because
most of the water has been absorbed. The colon
muscle contraction are slow or sluggish causing
stool move through colon too slowly.

26. CAUSES:
Diet (Lack of fibers & liquids)
 Lack of exercise
 Age
 Irregular bowel habits
 Drug induced
 Disease States/Conditions
Spasm of sigmoid colon
Dysfunction of myenteric plexus

27. SYMPTOMS OF CONSTIPATION
Infrequent defecation
Nausea
Vomiting
Anorexia
Feeling full quickly
Stools that are small, hard, and/or difficult to evacuate
Rectal bleeding
Weight loss (in chronic constipation)

28. Management of constipation
 Beginning with advice on lifestyle (including
exercise and adequate hydration)
 Dietary modification.
 Consumption of plenty of fresh vegetables, fruits,
milk, and water.
 Establishing regular bowel, eating and exercises
habits.
 Where lifestyle changes and dietary modification
are insufficient, a laxative may be considered.

29. LAXATIVES
Drugs that promote evacuation of bowels.
Based on intensity of action

30. MECHANISM OF ACTION
All laxatives increase the water content of the faeces
by:
a) A hydrophilic or osmotic action, retaining water
and electrolytes in the intestinal
lumen—increase volume of colonic content and
make it easily propelled.
(b) Acting on intestinal mucosa, decrease net
absorption of water and electrolyte; intestinal transit
is enhanced indirectly by the fluid bulk.
(c) Increasing propulsive activity as primary action
—allowing less time for absorption of salt and water
as a secondary effect.

31. Laxatives modify the fluid dynamics of the mucosal cell
and may cause fluid accumulation in gut lumen by one or
more of following mechanisms:
(a)Inhibiting Na+K+ATPase of villous cells—impairing
electrolyte and water absorption.
(b)Stimulating adenylyl cyclase in crypt cells—increasing
water and electrolyte secretion.
(c)Enhancing PG synthesis in mucosa which increases
secretion.
(d)Increasing NO synthesis which enhances secretion and
inhibits non-propulsive contrations in colon.
(e) Structural injury to the absorbing intestinal mucosal
cells.

32. CLASSIFICATION OF LAXATIVES
1. Bulk forming
Dietary fibre:Bran, Psyllium (Plantago), Ispaghula,
Methylcellulose
2. Stool softener
Docusates (DOSS), Liquid paraffin
3. Stimulant purgatives
(a) Diphenylmethanes:Phenolphthalein, Bisacodyl, Sodium
picosulfate
(b) Anthraquinones (Emodins): Senna, Cascara sagrada
(c) 5-HT4 agonist: Tegaserod
(d) Fixed oil: Castor oil
4. Osmotic purgatives
Saline laxatives, Lactulose, Sorbitol, PEG, Magnesium
oxide

33. Bulk-forming laxatives
 Bulk-forming laxatives are indigestible,
hydrophilic colloids that absorb water, forming a
bulky, emollient gel that distends the colon and
promotes peristalsis.
Common preparations include
Bran
Ispaghula
Methylcellulose and related compounds,
psyllium, or sterculia.
Bulk laxatives are of particular value in those with
small hard stools.

34. Bulk Forming Laxatives
Improve stool consistency and frequency with regular use
Ensure good fluid intake to prevent fecal impaction
Onset of action 2-3 days
Side Effects may include bloating, flatulence, distension

35. STOOL SOFTENERS
Docusates(Dioctyl sodium sulfosuccinate:DOSS)
It is an anionic detergent, softens the stools by net water
accumulation in the lumen by an action on the intestinal
mucosa. Dose: 100–400 mg/day; acts in 1–3 days.
Liquid paraffin
It is a viscous liquid mixture of petroleum hydrocarbons
that is pharmacologically inert.
Taken for 2–3 days, it softens stools and is said to lubricate
hard scybali by coating them.
Dose: 15–30 ml/day—oil as such or in emulsified form.

36. Stool Softeners
May be useful with anal fissures of haemorrhoids
Liquid paraffin is not recommended for treatment of
constipation
-risk of aspiration and lipid pneumonia
-long term use may result in depletion of Vit A, D, E, K

37. Stimulant laxatives
Stimulant laxatives (cathartics) induce bowel
movements through a number of mechanisms.
These include direct stimulation of the enteric
nervous system and colonic electrolyte and fluid
secretion.
Stimulant laxatives in current use include
Phenolphthalein 60–130 mg: LAXIL 130 mg tab.
To be taken at bedtime (tab. not to be chewed).
Bisacodyl 5–15 mg: DULCOLAX 5 mg tab; 10 mg
Senna
Castor oil

38. Stimulant Laxatives
 Increase intestinal motility by stimulating colonic nerves
 Useful with opioids
 Onset of action 8-12 hours
 Development of tolerance is reported to be uncommon
 Generally considered 2nd
line therapy in elderly due to risk
of electrolyte disturbances
 Other adverse effects include cramping, diarrhoea,
dehydration

39. Osmotic laxatives
Osmotic laxatives are soluble but non absorbable
compounds that result in increased stool liquidity due to
increase in fecal fluid.
saline laxatives such as magnesium hydroxide and
magnesium sulfate
poorly absorbed sugars such as lactulose or sorbitol,
and macrogols (PEG).
Non absorbable Sugars or Salts may be used for the
treatment of acute constipation or the prevention of
chronic constipation.
Magnesium oxide (milk of magnesia) is a commonly
used osmotic laxative. It should not be used for
prolonged periods in patients with renal insufficiency due
to risk of hypermagnesemia.

40. Osmotic Laxatives
Increase fecal water content
bowel distention
increased peristalsis
evacuation
Improving stool frequency
Onset of action – up to 48 hours
Metabolized by bacteria → flatulence

41. Lactulose It is a semisynthetic disaccharide of fructose
and lactose which is neither digested nor absorbed in the small
intestine—retains water.
Further, it is broken down in the colon by bacteria to osmotically
more active products.
In a dose of 10 g BD taken with plenty of water, it produces soft
formed stools in 1–3 days. Flatulence and flatus is common,
cramps occur in few. Some patients feel nauseated by its peculiar
sweet taste.
Onset of action: 48hrs
Dose: 15-30ml 8 hrly (10g/15ml)
Indication
Hepatic encephalopathy
Distal ulcerative colitis

42. Uses:
1.Functional constipation
2. Bedridden patients
3. To avoid straining at stools (hernia, cardiovascular
disease, eye surgery) and in perianal afflictions
(piles, fissure, anal surgery)
4. Preparation of bowel for surgery, colonoscopy,
abdominal X-ray
5. After certain anthelmintics
6. Food/Drug Poisoning

43. Adverse Effects:
1. Flairing of intestinal pathology, rupture of inflamed
appendix.
2. Fluid and electrolyte imbalance, especially
hypokalaemia.
3. Steatorrhoea, malabsorption syndrome.
4. Protein losing enteropathy.
5. Spastic colitis.
Contraindications:
1. A patient of undiagnosed abdominal pain, colic or
vomiting.
2. Organic (secondary) constipation due to stricture or
obstruction in bowel, hypothyroidism, hypercalcaemia,
malignancies and certain drugs.