5
Drugs which affect appetite Anti-
1
Sialagogues
Definition Drugs that reduce the flow of saliva.
Therapeutic Uses : to reduce salivation during
inhalation of volatile anesthesia by ether or
Often in monogastric small animals. chloroform.
Appetite
Drugs that increase the volume and Stimulants.
Atropine is commonly used as a preanesthetic.
fluidity of saliva. Act by blocking the muscarinic receptors of the
(Sialagogues) parasympathetic nervous system. (hyoscine&
Act by stimulating the muscarinic
hyoscyamine).
receptors. They may act by depressing directly the secretary
2 cells of salivary glands as by tannic acid and catechu.
Therapeutic
Uses 4
2-Direct
3 sialagogues
Improve the loss of
appetite in weak 1- Reflex sialagogues a) Direct Sialagogues: drugs acting by
(Bitters) Stomachic
animals. direct stimulation of vogues supplying
Stimulate saliva salivary glands as carbachol and
Mechanism of action: Bitters stimulate the taste buds on the physostigmine. (parasympathomimetic.)
production in tongue, so reflex stimulate salivation.
ruminants. b) Potassium iodide and sodium iodide
Can be administered orally as powder, drench, and electuary
Atropine Poisoning also count, and the MOA: increase saliva
or mixed with food.
secretion by irritate salivary glands
(dry mouth). a. Aromatic bitters : Orange, lemon peel.
during its excretion.
b. Non-Aromatic bitters: such as Gentian, quassia and brucin.
1 4
Notes Esophageal
obstruction
It’s well developed in suckling In small animals (dogs & cats),
animals as it allows orally Drugs act bones, or other foreign bodies
ingested fluids to pass directly on the becoming lodged in the
from esophagus to abomasum. esophagus esophagus.
2
Importance of In cattle lodged with pieces of
E .G. closure root vegetables causing bloat.
5
It prevents the fermentation of the milk. Treatment of
More over it’s closure prevents the E. obstruction
3
degradation of some orally administered Failure of
drugs, such as chloramphenicol& digitalis. E.G closure Drugs with Muscle Relaxant
Some drugs are harmful to the
It’s a common cause of bloat. spasmolytic, such as
microflora, which are present in the
rumen: tetracyclines, penicillins, & Atropine inhibit the closure of the 1- Acepromazine.
sulfonamides. groove partially. 2- Xylazine :(α2 agonist) with
If drugs entered the ruminoreticulum The dopamine inhibits the closure sedative & muscle relaxant
champers, it’s absorption becomes more completely.
slow compared to the absorption if
entered the abomasum
Inhibition can be stopped by
antidopaminergic.
3
1 Drugs affecting the
Systemic (general)
stomach
Definition anti-acids
Sodium alkaline salts that may be absorbed.
Drugs given orally to neutralize
The anti-acid effect is produced in the stomach
excess gastric acidity .
before before absorption and in the blood and
My occur following grain overloads
which leads to production of VFA. Antacids urine after absorption.
Sodium bicarbonate: → liberate CO2 → re-
2
Therapeutic stimulation of acid.
Uses Sod. & potassium citrates: neutralize without CO2
release.
For treatment of gastric ulcers & 4
Non systemic
hyperacidity dogs , cats. 5 (local) anti-acids
Gastric acid
2. Treatment of ruminal acidosis
secretion inhibitors
in ruminants. Insoluble alkaline salt produces
its anti-acid effect only in the
H2-antihistamines (histamine antagonists): Ranitidine & famotidine block gastric acid stomach.
secretion from parietal cells by blocking the H2-receptor. Calcium carbonate & magnesium
Sucralfate is an anti-ulcerative drug with cytoprotective effects on gastric mucosa.
carbonate neutralize excess
Sucralfate dissociates in the acid Ph of stomach tosucrose, octasulfate, tosucrose, &
aluminum hydroxide. The product of dissociation polymerizes to a viscous, sticky
acidity and liberate CO2.
substance which work as a protective effect by binding to ulcerated mucosa. Magnesium oxide, magnesium .
Misoprostol is synthetic prostaglandin E1 analogue that has cytoprotective effects and is trisilicate, and aluminum
used in dogs to reduce the risk of GI ulcers. hydroxide neutralize excess
Drugs affecting the
stomach Side Notes
1
Definition
FMD: foot and mouth disease.
Agents used to protect the Demulcents Gingivitis: red, swollen, bleeding
mucous membrane of GIT in gums.
cases of ulcer or inflammation. Pharyngitis is an inflammation of the
pharynx, resulting in a sore throat.
2 Enteritis is inflammation of the small
It includes intestine.
1. Insoluble salts: calcium carbonate, which is
protective, antiemetic, and antidiarrhea. 3
Therapeutic
Bismuth carbonate (sedatives). Aluminum
Uses
silicate (Kaolin) has an antidiarrhea effect.
2. Sugars: sucrose, lactose , honey & treacle. FMD.
3. Gums: acacia & tragacanthin. Gingivitis.
4. Animal proteins : gelatin and egg albumin. Pharyngitis.
Enteritis.
3
Drugs affecting the
1 Reflex or Local
stomach emetics
Definition
Act locally by irritating the gastric mucosa
Drugs produce vomiting in animals and reflexly stimulating the vomiting
that have vomiting centers.
center.
Emesis is not possible in horses,
ruminants, or rats. Inorganic salts such as sodium chloride,
The chemoreceptor trigger zone copper sulphate, and zinc sulphate.
(CTZ) is located on the medulla
Emetics
4
oblongata and connected to the Direct or Central
vomiting center. Emetics
CTZ carries dopaminergic R. So
dopamine induces vomiting, but 1. Apomorphine hydrochloride:
drugs with dopaminergic Rs. Alkaloid drugs derived from morphine act as potent
Antagonists R. inhibit vomiting. central dopamine agonists and directly stimulate CTZ &
2 vomiting C. Vomiting occurs within 2–3 min. after
Therapeutic subcutaneous injection.
Uses If emesis does not occur by the first dose,
apomorphine should not be repeated.
To remove oral toxic 2. Xylazine: α2-adrenergic agonist used for its
material. sedative in ruminants and horses, but administration
To remove a foreign body.
in dogs & cats causes vomiting and defecation.
3
Drugs affecting the
Local anti-
stomach emetics
4
Central
Drugs act by protecting the gastric
anti-emetics epithelium from irritation.
a) Anti-acids: act by gastric acid
Drugs act by inhibiting vomiting C. or neutralization to reduce symptoms of
by blocking dopaminergic Rs in CTZ. Anti- gastritis.
a) Metoclopramide (dopamine
antagonist): acts by blocking
emetics 1. Rapidly acting anti-acids (soluble in
water) as sodium bicarbonate.
dopaminergic Rs. on CRZ, so inhibits 2. The slower anti-acids are calcium
vomiting. The most useful drug for carbonate, magnesium carbonate, &
dogs & cats admin. orally & aluminum silicate (kaolin).
Parenterally. b) Demulcents, such as calcium
b) Phenothiazine derivatives, such as 1 2 carbonate, bismuth carbonate, and
promazine, chlorpromazine, and Therapeutic
Definition Uses aluminum silicate, act by coating the
acepromazine. They have sedative, gastric mucosa, leading to inhibition of
antihistaminic, and antidopaminergic the irritation.
activities. Drugs can stop Prolonged vomiting causes
c) Topical local anesthetics:
exhaustion, dehydration,
c) Antihistamines: diphenhydramine, vomiting in benzocaine & amethocaine
cyclizine, & meclizine HCl. hyponatremia and
animals having hypochloremia.
benzocaine. They act by depressing
d) Antimuscarinic : used in dogs and sensory nerve endings in the stomach
cats as atropine, hyoscine,
vomiting center. Antiemetics used To prevent
to prevent transmission of impulses to
dicyclomine HCl, and isopropamide emesis due to motion
vomiting C, leading to a reduction of
HCl. sickness during animal
vomiting.
transportation.
3
1 The carminatives
Definition family
The most common members of
Agent used orally aid the carminatives are the volatile oils:
expulsion of excess gases camphor, turpentine, peppermint, anise,
from the stomach, rumen and eucalyptus, clove, and cinnamon oils.
intestine by relaxing the Volatile compounds:
sphincters. Carminatives 1. Ether (spiritus etheri nitrosi).
2. Chloroform water.
4 Disorders
corelated with
2 carminatives
Therapeutic
Uses
The normal process of fermentation of cellulose
Flatulent colic. in rumen results in production of gas which
Tympany due to free gases. periodically removed by eructation.
Tympany may be caused due to ruminal stasis,
which occurs when eructation stops so the
gases are trapped.
