1. Drugs Acting on the Gastrointestinal
tract

2. GIT related disorders
In appetence Other disorders
Appetite stimulants Different drugs
Diarrhoea
Acids
Antiacids Antidiarhoeal
Indigestion Constipation
Digestants Laxatives and cathartics
Vomiting/Emesis
Emetics/antiemetics

3. Introduction
 Most of the GIT disorders are related
with motility
 Non specific treatment of GIT disorders
may be useful by
- Correction of fluid and electrolyte
balance
- Rest of the GIT
- Diet modification
- Provision of nutritional support
- Alleviation of visceral pain

4. Appetite stimulants
 Benzodiazepines
 Cyproheptadine
 Glucorcorticoids
 Bitters
 Zinc

5. Appetite stimulants
 Benzodiazepines
- Diazepam
- Oxazepam
Mode of action- Stimulation of GABA
Clinical use – Most in cats, less in Horses, dogs and
goats
Admn – Oral

6. Cyproheptadine
It suppreses the satiety center in the
brain by acting as serotonin and
Histamine (H1) antagonist
Clinica use – in cats and human, not in
dogs
Adverse effects – Excitement and
aggressive behavior in some cats

7. Glucocorticoids
Examples
- Prednisolone
- Dexamethazone
Mode of action – may be induce
euphoria
Adverse effects – Immunosuppression
and gastric ulcers may result

8. Bitters
These are plant derived compounds
containing alkaloids such as Nux
vomica
Mode of action – They stimulate
salivation

9. Zinc
It is essential for the sensation of taste;
therefore zinc supplements may
increase appetite in zinc-deficient
animals

10. ANTACIDS
They include
- Acid secretion inhibitors
- Proton pump inhibitors
- Locally acting antacids
- Gastric protectants

11. Acid secretion inhibitors
Histamine (H2) blockers
- Cimetidine
- Ranitidine
Mode of action – H2 stimulates the
proton (acid) pump in parietal cells.
H2 blockers block the H2 receptors
hence decrease HCL secretion

12. Proton pump inhibitors
Example Omeprazole
Mode of action – they inhibit H+-K+-
ATPase hence reduce hydrogen
secretion

13. Locally acting antacids
They include
- Aluminum salts (Aluminum hydroxide,
Aluminum carbonate, Aluminum
silicate)
- Magnesium salts (Magnesium oxide
(milk of magnesia), Magnesium
tricilicate
- They act by neutralizing gastric HCL

14. Gastric protective
Example is Sucralfate
This is a sucrose sulfate-aluminum
hydroxide complex
Mode of action – it polymerizes to a
viscous gel. The sulfate groups bind
to proteins in ulcerated tissue and
protect ulcers from acids and pepsin

15. DIGESTANTS
Introduction
Definition - Digestants are a group of
drugs used to promote the process of
digestion in the gastrointestinal tract
They include
- Pancrelipase
- Bile acids and salts

16. Pancrelipase
It consists of pancreatic enzymes (e.g.
lipase, amylase, trypsin)
Clinical use – Used to treat exocrine
pancreatic insufficiency in dogs, cats
and birds

17. Bile acids and salts
They include;
- Bile acids (e.g. cholic acid,
chenodeoxycholic acid)
- Semisynthetic bile acid derivatives
(e.g. dehydrocholic acid)
- Sodium salts of bile acids
Mode of action – they stimulate
choleresis (bile flow)

18. EMETICS
They include
- Centrally acting emetics
Apomorphine
Xylazine
- Peripherally acting emetics
Sodium Chloride
Syrup of ipecac (from Ipecacuanha)
Copper sulfate, zinc sulfate,
hydrogen peroxide

19. ANTI EMETICS
They include
- Antidopaminergic agents
- Antihistamines
- Anticholinergic agents
- Miscellaneous antiemetics

20. Antidopaminergic agents
Phenothiazine drugs
Acepromazine
Chlorpromazine
Promazine
Prochlorperazine
Metoclopramide
Butyrophenones
Droperidol
Haloperidol

21. Antihistamines
 Dimenhydrinate
 Diphenhydramine
 Promethazine

22. Anticholinergic agents
 Aminopentamide
 Propantheline
 Isopropamide
 Darbazine (isopropamide plus
prochlorperazine)

23. Miscellaneous antiemetics
Intestinal protectants and adsorbents
(kaolin, pectin, bismuth salts)
Locally acting gastric antacids (Mg
hydroxide, Mg silicate, Al hydrox., Al
silicate) may reduce vomiting caused
by gastric hyperacidity

24. LAXATIVES AND CATHARTICS
They are used for
- Relief of acute non-dietary
constipation
- Removal of poisons from the
gastrointestinal tract
- Prevention of Tenesmus in
advanced pregnancy or prolapse
- Evacuation of bowel prior to surgery
or radiography

25. LAXATIVES AND CATHARTICS
They include
- Osmotic cathartics
- Irritant cathartics
- Bulk laxatives
- Lubricants
- Surfactants

26. Osmotic cathartics
Examples
- Mg sulfate (Epsom salt), Mg oxide
- Sodium sulfate (Glauber’s salt)
- Polyethylene glycol electrolyte
solutions
- Sodium phosphate and sodium
tartrate mixtures (fleet enemas)

27. Irritant cathartics
Examples
- Castor oil
- Aloe
- Senna
- Cascara sagrada

28. Bulk laxatives
Examples
- Methylcellulose
- Agar
- Psyllium
- Wheat bran

29. Lubricants and surfactants
Lubricants - Mineral oil (liquid
petrolatum) and white petrolatum
Surfactants – Docusate

30. ANTI DIARHOEAL DRUGS
They include
- Opiates
- Anticholinergic agents
- Protectants and adsorbent agents

31. Opiates
They include
- Paregoric – a camphorated tincture
of opium
- Diphenoxilate
- Loperamide
- Codeine

32. Anticholinergic agents
They include
- Methoscopolamine
- Aminopentamide
- Propantheline
- Isopropamide

33. Protectants and adsorbent agents
Preparations
- Kaolin-pectin suspensions
- Bismuth sub-salicylate

34. DRUGS USED TO TREAT
INFLAMMATORY BOWEL DISEASE
Examples
- Sulfasalazine
- Olsalazine
- Tylosin
- Metronidazole

35. DRUGS FOR TREATMENT OF RUMINANT
GASTROINTESTINAL DISORDERS
Several groups
- Agents for inducing closure of the
esophageal groove
- Ruminotorics
- Rumen antacids
- Rumen acidifiers
- Viscosity-altering (antibloat) agents

36. Agents for inducing closure of the
esophageal groove
Example
- Milk
- Sodium bicarbonate (10% to calves)
- Copper sulfate (5% to calves, 2% to
lambs)
-

37. Ruminotorics
They include
- Bitters
- Cholinergics
- Opiate antagonists (eg naloxone)
- Rumen fluid transfer

38. Rumen antacids
Examples include
- Magnesium oxide
- Magnesium carbonate
- Aluminum hydroxide
- Calcium carbonate
- Ammonium carbonate

39. Rumen Acidifiers
Example
- Vinegar
- 4%-5% Acetic acid

40. Viscosity-altering (anti-bloat) agents
Preparations include
- Poloxalene
- Polymerized methyl silicone
- Mineral oil and
- Vegetable oil (e.g. soybean, peanut,
sunflower oil).