Drug acting on digestive system

DRUGS ACTING ON DIGESTIVE
SYSTEM
JAI NARAIN VYAS UNIVERSITY, JODHPUR
ASSISTANT PROFESSOR:- ASHWIN SINGH CHOUHAN
DEPARTMENT:- PHARMACOLOGY
E-MAIL:-ashwinsingh26061992@gmail.com

What do you mean by drug acting on
digestive system
ASC JNVU PHARMACY, JODHPUR

The Gastrointestinal (GI) Tract Includes the Mouth,
Stomach, Small Intestine (Duodenum, Jejunum, and Ileum),
Large Intestine (Cecum and Colon), Rectum, Anus, and Its
Accompanying Exocrine Glands (The Salivary Glands, The
Pancreas, and the Gallbladder).
Drugs Affecting the GI System are Used In the Treatment
of Gastric Acidity, Peptic Ulcers, and Gastroesophageal
Reflux Disease (GERD), Bowel Motility Disorders
Constipation, and Diarrhea), and For the Treatment of
Nausea and Vomiting.

Carminatives
Digestant
Bitter
Drugs used in constipation
Purgatives
Laxatives
Antispasmodics
Antacids
Drugs used in peptic ulcer
Antiemetic and emetics
antidiarrhoeals

CARMINATIVE
These Are Drugs Which Helps In Expulsion( Removal) of
Gases From Stomach and Intestine.
EXAMPLES:- Asafoetida, Ginger, Coriander Etc
USES:- Treatment of Flatulence ( gas in stomach), Used
In Colic ( Pain In Stomach)

MECHANISM OF ACTION
These Compounds Facilitates an Increase In Gastric
Emptying and are Mildly Irritating To The So, That
Peristalsis Is Increased, There By Relieving Gastric
Mucosa. Cramping and Expelling Gas. These Act By:
Mild Irritation Resulting In Increased GI Motility.
Liberating Carbon dioxide.
Peristalsis :- the involuntary constriction and relaxation of the
muscles of the intestine or another canal, creating wave-like
movements that push the contents of the canal forward

DIGESTANT
Digestants are Drugs Which Enhance the Process of
Digestion.
Examples:- Pepsin, Renin, pancreatin etc.
Pepsin (Digest Protein) Amino Acid
Renin (Chymosin) Caseinogen Insoluble Casein
Pancreatin Amylase, Trypsin, Lipase
RENIN:- Coagulated Milk (milk curdling enzyme)

BITTER
These Agents Stimulate Taste Buds and Produces Reflex
Secretion of Gastric Juice.
EXAMPLES:- Chirata, Gentian
USES:- Treatment of Anorexia (Loss of Appetite)
Appetizers
:-
secretion
of gastric
juice
called
appetite

DRUG USED IN CONSTIPATION

Laxatives, purgatives, or cathartics are substances
that loosen stools and increase bowel movements.
They are used to treat and/or prevent constipation.
Constipation is the infrequent or difficult evacuation
of the faeces.

PURGATIVE
Purgative Is a Medicine That Remove Unwanted
Waste From Body( Defecation)
Examples:-
Plantago Seeds ( Isabgol) ,
Milk of Magnesia ( Osmotic Purgative),
Methyl Cellulose ( Bulk Purgative)
USES- Treatment of Constipation.

LAXATIVES
Laxatives and Purgatives are Substances That
Loosen Stools and Increase Bowel Movements
Isabgol Is Good Remedy Used as Laxative
USE:- Treatment of Constipation.

THREE TYPES OF LAXATIVES ARE KNOWN:
Laxative Or Aperients: Milder Action, Elimination
of Soft But Formed Stools.
Onset Of Action: 12-72 Hours.
Purgative: Purgative are Moderate Laxative.
Onset Of Action: 6-8 Hours.
Cathartic: Stronger Action Resulting In More Fluid
Evacuation.
Onset Of Action: 0.5-3 Hours (Oral), 2-15 Minutes
(Rectal).

CLASSIFICATION:
 Bulk forming: Dietary fibre: Ispaghula
(Plantago), Methylcellulose
 Stool softener: Docusate (DOSS), Liquid
paraffin
 Stimulant purgatives: Senna, Sodium
picosulfate, Castor oil
 Osmotic purgatives [Saline (Osmotic)
Cathartics]:
 Magnesium salts: sulfate, hydroxide;
 Sodium salts: sulfate, phosphate; Sodium.
Potassium. tartrate; Lactulose

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

ANTISPASMODIAC
A Median That Relieve From Muscle Pain Especially
Smooth Muscle Such as In Bowel Wall
CLASSIFICATION:-
(Antimuscarinics/Anticholinergics):-
Dicyclomine, Belladonna, Hysine, Atropine
(Smooth muscle relaxant) :- Peppermint etc

ANTACID
Antacids are the drugs which are used to neutralise the
gastric contents.
Antacid occurs due to excessive secretion of HCL in
stomach.
Classification of Antacid
Systemic antacid ( absorbable):- systemic antacids are
soluble absorbable and capable to produce synthetic
alteration or alkalosis.
Examples:- NaHCo3

Non-systemic Antacids ( Non-absorbable):- These are
Not Absorbable To A Significant extent and Thus Do Not
extent The appreciable non- systemic antacids.
Examples:- Mg salts, Al salts, calcium bicarbonate etc
 Aluminum Containing Antacids:- Aluminum
Hydroxide, Dihydroxy Aluminum Sodium Hydroxide.
 Calcium Containing Antacids:- Calcium Carbonate.
Tribasic Calcium Phosphate.
 Magnesium Containing Antacids:- Magnesium
Hydroxide, Magnesium Oxide.

IDEAL PROPERTIES OF ANTACIDS
It Should Be Insoluble In Water and Has Fine Particle
From.
It Should Not Be Absorbable and Cause Systemic
Alkalosis.
It Should Be Stable and Does Not Produce Any Side
Effects.
It Should Be Readily Available.
It Should Cause Laxative or Constipatic Effect.
The Reaction Between Antacid and HCL Should Not
Produces Large Volume of Gas.
It Should Buffer In Ph Range of 4-6.

H + NaHCo3
Acid secretion
Parietal cell
HCL
Digestion Juice
Antacid
NaHCo3
Food Will Initiate Acid Secretion
H2Co3
H2O + CO2
HCL
Glass of
Digestion juice
HCL
Add Antacid tablet
NaHCo3 in HCL glass
1
3
2
Remove acid form HCL glass
Mechanism Action Of Antacid Drug
Discomfort due to acidity

PARIETAL CELLS
Parietal Cells Secrete Hydrochloric Acid and Chief Cells
Secrete Digestive Enzymes Such as Pepsin. These Cells
Secrete Their Products When Activated by Signals From
The Body Such as Hormones and Neurotransmitters.
MUCUS LAYER
It is a protective barrier to stomach acid, bile salts,
pancreatic enzymes, macromolecules. The mucus lining
your stomach helps prevent your stomach lining from the
negative effects of excessive exposure to acid or pepsin.

DRUGS USED IN PEPTIC ULCER

PEPTIC ULCER( Antiulcer Drugs)
Antiulcer drugs are used in the treatment of gastric and
duodenal ( peptic ulcer).
Antiulcer drugs promoting ulcer healing.
Why peptic ulcer occur?
Helicobacter pylori bacteria also responsible for ulcer production.
Imbalance between aggressive and defensive factors responsible
for peptic ulcer.
Aggressive Factor
Acid
Pepsin
Bile
H.Pylori
Drugs (NSAIDS)
smoking and alcohol
Defensive Factor
Mucous Membrane
HCO3,
Prostaglandin
phospholipids

CLASSIFICATION OF PEPTIC ULCER/ ANTIULCER
DRUG
Reduction Gastric Acid Secretion
Antihistamine Receptor Antagonist:- Cimetidine, Ranitidine etc.
Anticholinergic Drug:- Belladonna, Atropine etc.
Proton Pump Inhibitors (PPIs):- Omeprazole, Pantoprazole etc.
Prostaglandin Analogues:- Misoprostol.
Neutralize Gastric Acid ( Antacid)
Systemic:- Sodium Bicarbonate, Sodium Citrate etc.
Non-systemic:- Magnesium Hydroxide, Aluminum Hydroxide Gel,
Calcium Carbonate Etc
Anti Helicobacter Pylori Drug:- Clarithromycin, Amoxicillin,
Tetracycline Etc
Ulcer Protective:- Sucralfate, Colloidal Bismuth Subcitrate etc.
Ulcer Healing:- Carbenoxolone Sodium.

Acid
secretion
Parietal cell
Mucus
protective
layer
Mechanism Action Of peptic ulcer
Drug
Acid prevention
Acid attack
Ulcer
generation
Ulcer protective:- sucralfate,
bismuth colloidal subcitrate
Antacid:- Aluminum
Hydroxide Gel, Magnesium
Hydroxide
H2 histamine Inhibitor antagonist:
Cimetidine Ranitidine
DRUGS
Inhibiting Gastric Acid Secretion
K+ H+
K+ H+
Neutralize
acid
Bind
Antagonist
Proton Pump Inhibitors (PPIs):-
Omeprazole, Pantoprazole etc.
Antibiotic
Clarithromycin
, Amoxicillin
HCL
Digestion Juice

MOA OF ANTIULCER DRUG
Inhibitor Are Reduced Acid Stimulate
Vagus Nerve Stimulate
Ach
Histamine + H2 Receptor
More Acid Secrete( HCL)
Ulcer
-
Activated release of histamine
Anticholinergic
Ach release
H2 receptor blocker
-
Proton pump
inhibitors
suppress acid
secretion
-
Antacid
Neutralize acid
secretion

ANTIEMETIC AND EMETICS
VOMITING : It's Not A Disease Its Indication of
Certain Diseases Vomiting Occur Due To Stimulation
of Vomiting Center That Respond To Inputs From:
 Chemoreceptor Trigger Zone (CTZ) Stimulation.
 Disturbance of Vestibular System.
 Higher Cortical Center Stimulation (CNS).
 The Periphery (Pharynx, GIT) Via Sensory
Nerves.

Three Types of Vomiting:-
Morning Sickness:- starting 3 month of Pregnancy.
Motion Sickness:- Travelling Time.
Diarrhea Sickness:- Eating Junk Foods.
EMETICS
This are Drugs Which Produce Vomiting.
Classification Of Emetic
Stimulate of CTZ:- apomorphine, morphine etc
Irritants of Gastrointestinal Mucosa:- mustard, copper
sulphate, sodium chloride etc

ANTIEMETICS:
It Is a Drug That Is Effective Against Vomiting and Nausea.
CLASSIFICATION OF ANTIEMETIC
Anticholinergic Drug :- Hyosine, Dyclomine
H1 Antihistaminic Drug :- Promethazine, Doxylamine
Neuroleptics ( D2 Blockers) :- Chlorpromazine
Prokinetic :- Metoclopramide, Domperidone
5-HT3 Antagonist :- Ondansetron. Ramosetron
NK1 Receptors Antagonist :- Aprepitant
Other Drugs :- Dexamethasone, Benzodiazepine

CTZ
Blood Vessels
Cortex
Bad smell
bad matter
Medulla
oblongata
5HT
PG
Ear osssicles vibrate ( motion
sickness)
5HT
Mechanism Action Of
Antiemetic Drug
G.I.T
Cerebellum
VC
Brain

Neurotransmitter Classification Antiemetic Drug Mechanism of Action
Acetylcholine (M1) Anticholinergics scopolamine
Blocks ACh receptors in
vestibular system
Histamine (H1) Antihistamines meclizine
Blocks H1 receptors and
thus blocks ACh in
vestibular system
Dopamine (DA2) Dopamine antagonists prochlorperazine
Blocks dopamine in CTZ
and may block ACh
Dopamine and ACh
(DA2 and M1)
Prokinetics metoclopramide
Blocks dopamine in CTZ
and stimulates ACh in GI
tract
Serotonin (5HT) Serotonin antagonists ondansetron
Blocks serotonin in GI
tract, CTZ, and VC
Substance P (NK1) Neurokinin antagonists aprepitant
Inhibits substance P
neurokinin receptors
Cannabinoid (CB1)
Tetrahydrocannabinols
(THC)
dronabinol or medical
marijuana
Activated CB1 receptor
leading to inhibitory
effects on cerebral
cortex

DIARRHOEA
More Frequently Passage of Poorly Formed Stool.
W.H.O = 3 or More Than 24 Hours
Cause
Increase Secretion By Intestinal Mucosa.
Increase Luminal Osmotic Pressure
Inflammatory of Mucosa
Decrease Electrolyte and Water Absorption= H2O in
stool
Microbial Infection
Other cause – infection, toxin, anxiety, drug induced.
Virus- rotavirus, corona virus, astrovirus
Bacteria- E-coli, salmonella, Vibrio cholerae

ANTIDIARREAL DRUG
Antidiarrheal Is a Drug That Is Used To Slow Down or Stop
Loose Stools (Diarrhea).
The First Category
Refers to antidiarrhoeal adsorbents. They work best on mild
chronic diarrhoea. Kaolin is an example
The Second Category
Refers to inhibitors of intestinal movement. They control
diarrhoea by producing a direct relieving effect on intestinal
peristalsis. Diphenoxylate and loperamide are common
examples.

CLASSIFICATION OF ANTIDIARREAL DRUG
Antimicrobial Agents:- Norfloxacin, Ciprofloxacin,
Metronidazole Etc
Probiotics( Good Bacteria) :- Lactobacillus, Bacillus Etc
For Inflammatory Bowel Disease:-
5- Amino Salicyclic Acid:- Salfosalazine, Osalazine,
Mesalazine Etc
Glucocorticoids:- Predenisolone, Hydrocortisone Etc
Immunosuppressant:- Azithioprene, Methotrixate Etc
Non Specific Antidiarreal Agents
Absorbant:- Kaolin , Isapghula, Methycellulose Etc
Anti Secretory:- Bisubsalicylate, Anticholinergic Etc
Antimotility:- Codeen, Loperamide Etc

THERE ARE THREE COMMON MECHANISMS OF
ACTION OF ANTIDIARRHEAL MEDICATIONS
Adsorbents, Which Help Eliminate The Toxin or Bacteria
From The GI Tract .
Antimotility Agents Which Slow Peristalsis.
Probiotics
Which Help To Restore The Normal Bacteria Found In The
Lower Intestine.
Oral Rehydration Agents May Also Be Used In Patients
With Diarrhea To Replace Fluid And Electrolyte Loss, But
They Do Not Treat The Diarrhea.

Mechanism Action of Adsorbent
Adsorbent Medications Work By Coating The Walls Of The GI Tract And
Binding The Causative Bacteria Or Toxin For Elimination From The GI
Tract Through The Stool.Bismuth Subsalicylate Also Decreases The Flow
Of Fluids And Electrolytes Into The Bowel, Reducing Inflammation Within
The Intestine.
Mechanism Action of Antimotility
Antimotility Medications Help To Treat Diarrhea By Slowing Peristalsis.
There Are Two Categories Of Antimotility Medication: Anticholinergics And
Opiate-like Medication.
Mechanism Of Action of Anticholinergics
Hyoscyamine Is An Anticholinergic That Works On The Smooth Muscle Of
The GI Tract To Inhibit Propulsive Motility And Decreases Gastric Acid
Secretion.
Mechanism Of Action of Probiotics
Probiotics Help Replenish Normal Bacterial Flora In The Gastrointestinal
Tract. ASC JNVU PHARMACY, JODHPUR

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