1. DRUGS ACTING ON GIT
Presented by
Dr. Sannithi Nagarjuna
Coordinator for RIPER-GPAT Cell,
Hyderabad Academy &
Online GPAT Academy
7899107907
9885784793
nagarjunaspharma@gmail.com
2. Diseases - Caused by pathogenic/harmful microorganisms
e.g. Tuberculosis, Leprosy, Typhoid, Malaria
Disorders - due to altered/abnormal functioning of any body
system
e.g. Diabetes mellitus, Peptic ulcer, Hypertension, Hypotension,
Hyperthyroidism, Hypothyroidism
3. PHYSIOLOGY → Study of normal functioning
of body systems
PATHOPHYSIOLOGY → Study of disorders
PHARMACOLOGY → Study of drugs
4. MAJOR PARTS OF GIT
1. Stomach → acid/Hcl secretion → digestion(decrease in size),
→ To kill Microorganisms
2. Small Intestine → Absorption
3. Large Intestine → Unabsorbed substances eliminated through
feces and the process called as defaecation
5. LESS PARTICLE SIZE ( DIGESTED COMPOUNDS WILL REACH)
LARGE SURFACE AREA ( DUE TO VILLI AND MICROVILLI)
LIPOPHILICITY
NONPOLAR
UNIONIZED FORM ( WEAK ACIDIC TO WEAK BASIC PH AND MOST OF
PHARMACEUTICAL DRUGS ARE EITHER WEAK ACIDS OR WEAK
BASES)
SMALL INTESTINE
6. DISORDERS RELATED TO GIT
1. Peptic Ulcer ( Increased secretion of acid )
2. Achlorhydria ( decreased/ absence of acid secretion)
3. Emesis
4. Diarrhoea ( Increased passage of stools)
5. Constipation (Decreased passage of stools)
7. DRUGS ACTING ON GIT
1. Antiulcer drugs
2. Drugs for Achlorhydria
3. Emetics & Antiemetics
4. Antidiarrhoeal agents
5. Dugs for constipation/Laxatives
8. PEPTIC ULCER
âť– Characterized by excessive secretion of acid (acidity)
âť– Ulcers mean injuries/wounds due to long term existence of acidity
âť– Occurs in the areas highly exposed to gastric acid
âť– Stomach and duodenum are highly exposed to acid
âť– Ulcers in the stomach called as gastric ulcers
âť– Ulcers in the duodenum called as duodenal ulcers
10. Homeostasis
Maintenance of balance /equilibrium inside the body called as
homeostasis.
The major reason for disorders is disturbance in homeostasis.
Ex:
Maintenance of acid secretion, body temperature, blood
pressure, pulse rate etc.
16. ANTIHISTAMINES(H2 RECEPTOR BLOCKERS
Cimetidine - first drug, antiandrogenic action, withdrawn
from the market
Ranitidine - Popular brand names are RANTAC,
ZANTAC
Famotidine - Most potent drug
17. Proton Pump Inhibitors (H+ k+ ATPase Inhibitors)
âť‘ Highly effective
âť‘ Long term use decrease the release of intrinsic factor
which is essential for the absorption of vitamin B12 that
results in pernicious anemia
19. PG ANALOGUES
• Decrease acid secretion
• Increase bicarbonate and mucus secretion
• Also called as cytoprotective agents
• Used to treat NSAIDs induced ulcers
23. SYSTEMIC ANTACIDS
They enter into systemic circulation, they produce
systemic alkalosis and they are not preferred due to
this reason.
24. NONSYSTEMIC ANTACIDS
They will not enter into systemic circulation, produce local action and
they are highly preferred.
Aluminium salts produce constipation and magnesium salts produce
laxation, hence both should be used in combination.
MAGALDRATE is a combination of both in the body broken down into
aluminium hydroxide and magnesium hydroxide.
26. ULCER PROTECTIVES
They form a layer on the ulcers and they will protect
the ulcers from direct exposure to acid or any other
irritants
27. ULCER HEALING DRUGS
Carbenoxolone sodium obtained from Glycyrrhiza glabra
( Liquorice).
Due to lignin content and saponins they exhibit wound healing
property.
28. ANTI H.PYLORI DRUGS
âť– H. Pylori is a gram negative bacteria
âť– Treatment includes some of antibacterials and
antiprotozoals
29. DRUGS FOR ACHLORHYDRIA
âť– Rarest condition
âť– Majorly seen in children till 3 years of age
âť– Due to this they have frequently indigestion, vomiting and
infections
âť– Drugs used include Cholinergics like Carbachol, Bethanechol
30. EMETICS & ANTIEMETICS
Emetics are the agents which produce nausea and vomiting.
The only use of emetics is in the treatment of poisoning.
31. But they have some limitations like/they are not suitable in the
following conditions:
âť– If the patient is unconscious
âť– If the poison is already absorbed
âť– If the poison is strong acid/ strong base/corrosive which cause
further damage to the oesophagus
âť– If the poison is detergents/petroleum products which could be
aspirated into lungs
âť– Substance ingested likely to cause rapid onset of drowsiness or
seizures
34. CONDITIONS ASSOCIATED WITH VOMITING
Motion sickness (Vomiting during Journey/motion)
Morning sickness ( Vomiting during pregnancy)
Drugs like Levodopa
Conditions like Migraine
Anticancer drugs and radiation therapy
Excessive eating, excessive drinking & Bad smell/odor
35. Vomiting occurs due to stimulation of Vomiting centre (Emetic centre).
Vomiting centre is controlled by two centres named as CTZ
(Chemoreceptor Trigger Zone, located in CNS) & NTS (Nucleus
Tractus Solitarius, located in GIT).
CTZ is having receptors like D2, 5-HT3 & NK1 receptors and stimulation
of CTZ takes place due to stimulation of any one of the receptors.
Stimulation of NTS takes place due to excessive stimuli from
stomach.
36. MOTION SICKNESS
Any form of travel on land, in the air or on the water can
bring on the uneasy feeling of vomiting.
Children between the ages of 2 and 12 are most likely to
suffer from motion sickness.
Motion sickness is caused by a conflict between signals
arriving in the brain from the inner ear, which forms the
base of the vestibular system, the sensory apparatus that
deals with movement and balance, and which
detects motion mechanically.
Motion sickness occurs due to stimulation of muscarinic
and H1 receptors in vestibular apparatus which further
stimulates CTZ.
37. Receptors Present in CTZ Reason for the Stimulation
D2 Morning sickness
(Vomiting during pregnancy)
Drugs like Levodopa
Conditions like Migraine
5-HT3 Anticancer drugs and radiation
therapy
NK1 Excessive release of substance
P due to chemotherapy
Stimulation of NTS takes place due to excessive stimuli from
stomach observed in case of excessive eating, excessive drinking &
bad smell/odor.
40. ANTIHISTAMINES (H1 RECEPTOR BLOCKERS)
Ex: Promethazine,
Diphenhydramine,
Dimenhydriate,
Cyclizine
Anticholinergics and antihistamines exclusively used for the
treatment of motion sickness and they should be taken atleast 1
hour before the commencement of journey and they are also
effective in morning sickness.
41. D2 RECEPTOR BLOCKERS
(NEUROLEPTICS)
Which are mainly used to treat
âť– Morning sickness (Vomiting during pregnancy)
âť– Levodopa induced vomiting
âť– Migraine induced vomiting
Ex: Chlorpromazine, Haloperidol- Extrapyramidal side
effects (Parkinsonism like symptoms)
42. 5-HT3 RECEPTOR BLOCKERS
Which are mainly used to treat
âť– Anticancer drug induced vomiting
âť– Radiation therapy induced vomiting
Ex: Ondansetron, Granisetron
43.
44. NK1 RECEPTOR BLOCKERS
Which are used to treat substance P induced
vomiting due to chemotherapy and in case of injuries
Ex: Aprepitant
45. GASTROPROKINETIC AGENTS
Which increase the motility of GIT allowing the fast passage of
contents from stomach to intestine.
As a result of this mechanism contents present in stomach for less
time hence there is no chance of vomiting.
Due to this mechanism they produce diarrhoea as a side effect.
They stimulate 5-HT4 receptors present in GIT allowing the release
of Acetylcholine which increase the peristaltic movement of GIT.
46. Ex:
Metoclopramide→ also has D2 receptor blockade mechanism
Domperidone → also has D2 receptor blockade mechanism
Cisapride
Mosapride
Tegaserod
47. ADJUVANT ANTIEMETICS
Which alone may not have antiemetic property but
they increase the activity of other antiemetics.
Ex: Benzodiazepines
Corticosteroids
Cannabinoids (DRONABINOL, NABILONE)
48. Condition Drug of Choice
1. Motion Sickness A) Metoclopramide
2. Levodopa induced vomiting B) Hyoscine
3. Chemotherapy induced vomiting C) Aprepitant
4. Substance P induced vomiting D) Cannabinoids
5. Gastroprokinetic with D2 receptor
blockade property
E) Haloperidol
6. Adjuvant antiemetic F) Ondansetron
51. ANTIDIARRHOEAL AGENTS
âť– Used for the treatment of diarrhoea
âť– Diarrhoea is characterized by increase in the frequency of passage of
stools
âť– Mostly diarrhoea is a disease and very few cases it is considered as a
disorder.
âť– Most of the times diarrhoea occurs due to contamination with microorganisms
(Disease) and some times it occurs due to increased peristaltic movement of GIT
(Disorder).
52. âť– Appearance of more water in the stools called as watery/loose
stools → Indicates bacterial infection
❖ Appearance of blood in the stools called as Dysentery → caused by
Shigella
❖ Appearance of pus in the stools called as Amoebiasis → caused by
Entamoeba histolytica
❖ Severe vomiting with diarrhoea observed in case of Cholera →
caused by Vibrio cholera
âť– Fever with diarrhoea observed in case of Salmonella infection
âť– Travellers diarrhoea Caused by E.Coli
53. REHYDRATION
Severe diarrhoea results in dehydration, some times lead to death.
Severe stage of dehydration is identified by loss of urine output.
Dehydration will be corrected by Rehydration that can be done by
either oral route or IV depends upon the emergency.
Composition usually includes
Sodium chloride Electrolyte replacement
Potassium chloride Electrolyte replacement
Sodium
bicarbonate/Sodium
citrate
Buffer
Glucose Nutrient replacement
Water Fluid replacement
54. Antidiarrhoeal agents are classified into two types:
I. Specific Antimicrobial agents
Which are used when the diarrhoea is caused by specific
microorganism
II. Nonspecific Antidiarrhoeal agents
Which are used when the diarrhoea is caused by
increased peristaltic movement of GIT
55. SPECIFIC ANTIMICROBIAL AGENTS
Antibacterials like
Ex:
Fluoroquinolones like Ciprofloxacin, Norfloxacin, Gatifloxacin,
Levofloxacin
Tetracyclines
Co-trimoxazole
Antiprotozoals like
Metronidazole, Tinidazole
58. The official name given to 5-Amino Salicylic acid (5-ASA) is
MESALAMINE (MESALAZINE).
2. OLSALAZINE
Which consist of 2 molecules of 5-Amino Salicylic acid (5-ASA).
3. ANTICHOLINERGICS
60. DRUGS FOR CONSTIPATION
Constipation is characterized by decrease in the passage of stools
or difficulty in the passage of stools.
Drugs for constipation include
Aperients → Very milder
Laxatives → Milder
Purgatives → Stronger
Cathartics → very Stronger
61. CLASSIFICATION OF LAXATIVES
They are classified into 4 types
1. Irritant/Stimulant laxatives
2. Bulk forming laxatives
3. Osmotic/Saline laxatives
4. Surfactant laxatives/ Stool softeners
64. BULK FORMING LAXATIVES
They are not digested and they are not
absorbed.
Due to indigestion, all bulky material reach to
the large intestine, increases bulkiness and
causes free passage of stools.
66. OSMOTIC/SALINE LAXATIVES
They are not absorbed and they cause retention of
water.
Unabsorbed compounds will reach large intestine and
due to retention of water swelling takes place that
increases bulkiness.
69. SURFACTANT LAXATIVES/ STOOL SOFTENERS
Due to increased reabsorption of water hardening of
stools will result that causes difficulty in the passage of
stools.
Drugs are surfactants which reduce interfacial tension
and increases water incorporation that soften the
stools.
Ex: DOCUSATES (Dioctyl Sodium Sulfosuccinate),
MINERAL OIL
70. Presented by
Dr. Sannithi Nagarjuna
Coordinator for RIPER-GPAT Cell,
Hyderabad Academy &
Online GPAT Academy
7899107907
9885784793
nagarjunaspharma@gmail.com