Transcript The digestive tract plays a role of bringing life sustaining elements

The digestive tract plays a role
of bringing life sustaining
elements into the body and
taking waste products out of it.
Flow of material occurs by
peristalsis. A wavelike motion
of longitudinal and circular
muscle fibers. Another process
is segmentation..periodic
repeating intestinal constrictions
http://www.youtube.com/watch?v
=o18UycWRsaA
Peristalsis
Regulation of the actions is
controlled by the autonomic
nervous system. This consists of
the
Sympathetic branch
Parasympathetic branch
Parasympathetic stimulation
increases intestinal motility,
increases secretions and relaxes
sphincters
Cholinergic drugs stimulate
these actions
Anticholinergic drugs inhibit
these actions
Gastrointestinal drugs
help maintain the unobstructed
and regulated flow of food into
the body and waste products out
of the body
Types of Gastrointestinal drugs
Saliva Stopping : Antisialogues
These drugs can be administered
I.V, I.M or SQ, and are often
given secondary to anesthetic
use.
These anticholinergic drugs block
the effects of acetylcholine (a
neuro transmitter) at
parasympathetic nerve endings
These drugs are used to control:
* hypersalivation
*vomiting
*diarrhea
*excessive gastric secretions
Glycopyrrolate (Robinul)
Atropine
Diarrhea Stopping Drugs:
Diarrhea is not a disease, but a
sign of an underlying problem
and can cause excessive fluid
loss and a decrease in the
uptake of nutrients.
Antidiarrheals decrease
peristalsis allowing fluid
absorption from the intestinal
contents. These include:
*anticholinergics
*protectants
*adsorbents
*narcotic analgesics
Anticholinergics
*used to treat tenesmus
these drugs should be used with
caution as motility may already
be decreased.
Protectants/Adsorbents
*coat the inflamed intestinal
tract with a protective layer
*binding bacteria, digestive
enzymes and or toxins to
protect the mucosa
Narcotic (Opiate related drugs)
*decrease intestinal secretions
and flow of feces, increasing
segmental contractions resulting
in increased intestinal
absorption
Probiotics
*seed the gastrointestinal tract
with beneficial bacteria. Some
forms of diarrhea are caused by
the disruption of normal
bacteria flora
Metronidazole is an antibiotic
that is effective against
anaerobic bacteria and may be
used to regulate intestinal
bacteria and help return the
stool to normal consistency
Stool Loosening
laxative: loosens bowel contents
and encourages evacuation of
stool
cathartic: harsher laxative
resulting in watery stool and
abdominal cramping
purgative: harsher cathartic.
Types of laxatives:
*osmotic
*stimulant
*bulk forming
*emollients (stool softener)
Osmotic:
Include salts or saline, lactulose
and glycerin.
These salts pull water into the
colon and increase the water
content in the feces.
Stimulant laxatives increase
peristalsis by chemically
irritating sensory nerve endings
Bulk forming laxatives consists
of natural fibrous substances
that absorb water into intestinal
tract, increase fecal bulk
stimulate peristalsis resulting in
large soft stool production
Emollients are stool softeners,
lubricants, and fecal wetting
agents. These drugs are not
absorbed systemically and have
few side effects
Antiemetic Drugs
The act of vomiting is controlled by the
vomiting center in the medulla of the
brain. Acetylcholine is the
neurotransmitter for the vomiting center.
This center gets input from pathways including
*equilibrium changes
*pain
*fear
*intracranial pressure changes
*vagus nerve stimulation
*activity in chemoreceptor trigger zone (CRTZ)
Dopamine is the
neurotransmitter for the CRTZ
and stimulation of the CRTZ
results in dopamine release and
stimulation of the vomiting
center.
Types of antiemetics
*Phenothiazine derivatives:
inhibit dopamine in CRTZ.
Antihistamines: block input from
the vestibular system to the
CRTZ
Anticholinergics block
acetylcholine which decreases
intestinal motility. HOWEVER
these drugs also decrease gastric
emptying and may in fact
increase the tendency to vomit
Procainamide derivatives block
the CRTZ and speed gastric
emptying. Do not use in
obstructed animals due to the
stimulation of gastric motility
Vomit Producing Drugs:
Emetics
used in the tx of poisonings and
drug overdoses.
Check with poison control prior
to administering emetics
Remember…
horses, cattle sheep and goats are
unable to vomit
Apomorphine
stimulates dopamine receptors in
the CRTZ. Given SQ, IM or
topically in the conjunctival sac
Xylazine (Rompun)
induces vomiting in cats as a side
effect of its use as a sedative
=
Ipecac syrup, salt and hydrogen
peroxide are also commonly
used to induce vomiting.
Activated charcoal may be
given to reduce absorption of
toxins when vomiting is
contraindicated
Ulcer stopping Drugs
Antiulcer drugs: prevent the
formation of ulcers
Antiactids: promote ulcer
healing
Histamine-2: prevent acid reflux
by reducing gastric acid
secretion.
Antifoaming Drugs.
Used in ruminants who are
subject to acute frothy bloat.
The rumen distends with gas
that mixes with fluid to form a
froth which can asphyxiate the
animal
Motility Enhancing Drugs
used for treating constipation,
chronic hairballs or used after
surgery to increase GI motility
Enzyme Supplementing Drugs
used in cases of Pancreatic
Enzyme Insufficiency (PEI)
Care should be taken
when handling this drug,
it can be irritating to skin
and to nasal passages
Dental Prophylaxis
attention should be given to the
oral cavity in any gastrointestinal
condition.