Gastrointestinal Drugs Flashcards
The enteric nervous system is an extensive network of interconnected ____ and ____
interneurons within the gastrointestinal ___ that can control gut function _______ of the CNS
sensory, motor, wall, independently
The enteric nervous system is characterized by the presence of a complex intrinsic neural network that includes the _____
plexus and the ______ plexus
myenteric, submucosal
The submucosal plexus is located under the ______ layer of the gut. The myenteric plexus
resides between the ______ ____ muscle layer and the ____ _______ muscle layer
submucosal, inner circular, outer longitudinal
The ENS is extensively innervated by ________ _______ nerve fibers.Its sensory and motor interneurons can also be influenced by the CNS through input from _____ and ______ subdivisions
nonadrenergic-noncholinergic (NANC), sympathetic, parasympathetic
Myenteric plexus
Yellow represents nerve endings
Plexus submucosas
Emesis is a complex reflex activity (______ reflex) and its coordination is centered in the _______. Although several afferent pathways may be responsible for initiating emesis, all signals are
coordinated by the ____ center (______ center) located in the ____ _______. An important structure outside the GI-tract that supplies afferent input is the ________ ________ _____. This is sensitive to the presence of ____ and _____ in the blood
protective, brainstem, emetic, vomiting, mid brainstem, chemoreceptor
trigger zone (CTZ or CRTZ), drugs, toxins
Emesis is _________ induced to empty the ____ portion of the digest tract. List the examples in which emesis is induced:
A number of substances induce emesis by:
* Distending the ______, ______, _____, or _______ ( _______ organs)
* ________ the epithelium of the GI-tract (gastric _____ or _____)
pharmacologically, anterior
→ Preparation for induction of general anesthesia (food in the stomach)
→ Treatment of ingested, noncorrosive poisons
pharynx, esophagus, stomach, duodenum, hollow, Irritating, mucosa, pharynx
Peripherally acting (reflex) emetics
* Distention with ____ water or ____ can induce the emetic response
* In case of toxin ingestion, administration of ____ water by _____ tube may help ____ poisons
* Emesis can be induced in dogs by oral administration of a solution of: (1) Pharyngeal placement of a small amount of plain ____ _____ or neutral ____ _____, such as sodium carbonate OR (2) Orally administered _______ ______ (__%) often induces emesis rapidly in cats and dogs → fatal ______ of hydrogen peroxide foam is possible!
Copper sulfate (1%), zinc sulfate (1%)
warm, saline, warm, stomach, dilute
warm saturated (strong) sodium chloride
table salt, salt crystals, hydrogen peroxide, 3, aspiration
Prokinetic drugs increase GI ______, enhance the transit of ______ contents, and are used in ___ and ____ animals → occasionally in ruminants to stimulate gastric _______, ____ or _____ motility
* Intestinal motility is ↓ after intestinal disease, surgery → can lead to ____
motility, intraluminal, small, large, emptying, rumen, intestinal, ileus
Metoclopramide is a ____-soluble derivate of ____-________ __. It has a central (_________) and peripheral (________ and stimulator of ______
receptors) effects.
lipid, para-aminobenzoic acid, antidopaminergic, antidopaminergic, cholinergic
Metoclopramide has multiple actions:
→ D2 ______
→ Serotonin (5-HT3) _______
→ Serotonin (5-HT4) ______
→ Increase in the release of ____ in the ____-tract
→ Increase gastric _____
→ Increase ____ of the esophageal sphincter
→ Stimulates motility of the _______ (less effect on ____ segments)
→ Endocrine effects: transient increase in ______ and ______.
antagonist, antagonist, agonist, Ach, GI, emptying, tone, duodenum, distal, prolactin, aldosterone
Prokinetic drugs increase ?
GI motility
Metoclopramide is used in small animals to:
1. Stimulate ____ upper motility following _______ surgery (for gastric _____)
2. _______
3. Postoperative ____
4. Gastric _______
5. Idiopathic _____
–> Contraindicated in GI ______ or ______.
normal, corrective, dilation, Volvulus, ileus, ulceration, gastroparesis, obstruction, perforation
Metoclopramide: use in horses
* Some equine surgeons used infusion of metoclopramide to reduce __________ ____
* It may stimulate _____ ______ but not large bowel
* Undesirable side effects are common → ________ changes and ______
pain
postoperative ileus, small intestine, behavioral, abdominal
Metoclopramide: use in ruminants
* The clinical use of metoclopramide in large animals is ____ common
* It has a little usefulness in ____. It may ↑ the motility of the _____ in cattle and in sheep
* Metoclopramide is used successfully in cattle with functional ______ ______
* At doses higher than 0.1 mg/Kg in calves cause ?
less, cattle, rumen, pyloric stenosis
severe neurological side effects
Cisapride
* Cisapride was removed from the market → serious _______ and _____ in people. These
reactions have not been reported in _____
* It is still available via ______ pharmacists
* Cisapride has a great ______ effect. Agonist for the __-___ receptor on myenteric neurons and
antagonist for __-____ receptor → It may enhance release of ___ at the myenteric plexus
* It causes dose-dependent increased activity at ___ ____ sites: (?)
arrhythmias, deaths, animals, compounding, prokinetic, 5-HT4, 5-HT3, ACh, all GI
Esophagus, stomach, jejunum, ileum, small intestine, and colon
Cisapride
Clinical use in small animals
➢ treatment for ________ reflux, _____
gastric emptying, and _____ bowel motility
disorders
➢ Compared to ________, cisapride is
more effective for increasing ____ esophageal
sphincter ____ in dogs
➢ Cisapride has been used for treating chronic _______ in cats (effect on colonic _____ muscle)
gastroesophageal, delayed, small, metoclopramide, lower, tone, constipation, smooth
Domperidone is a dopamine (D2) _______. It may also have α1-receptor _____ and serotonin (5-HT2) _______ effects
* Its mechanism of action and prokinetic effects are similar to _____
* Domperidone does not cross the ____
* Its peripheral effects accelerate _____ intestinal transit. ______ activity is unaffected
_______ drugs increase GI motility
antagonist, antagonist, antagonist, metclopramide, BBB, small, Colonic, Prokinetic
Domperidone
* Domperidone has been investigated for use in horses to treat _____ toxicity and _____
* The oral absorption in horses is only __- ____%. ____ administration of ____ mg/Kg (the approved dose) had no effect on GI function but at __ mg/Kg ↑ stomach emptying
* ↑ digital laminal microvascular blood flow (horses) → ___________ ____ receptors.
Treatment of laminitis?
Fescue grass toxicosis: forage related disease involving the endocrine disruptive effect of ______ _____ (produce by fungus Neotyphodium coenophialum) on prolactin secretion
fescue, agalactia, 1, 1.5, PO, 1.1, 5, antagonist α2, ergot alkaloids
Erythromycin → a ________ antibiotic used to treat ______ infections
* Erythromycin stimulates GI motility at ____ doses → much lower than the antibacterial dose
* It stimulates GI motility via: activation of _____ receptors, release of endogenous ______ or _____ mechanisms in the upper GI tract
* Motilin is a _______ released from endocrine cells of the ________ mucosa. It ____ the motor contraction
* Most of the motilin receptors are on the ______ and _____ intestine
* Erythromycin is used clinically to increase gastric ______ and for the therapy of ______
esophagitis
* Concerns: may cause _______ (effect on the normal bacteria flora of the _______) and its routine use may promote antibacterial _______.
macrolide, bacterial, low, motilitin, motilitin, cholinergic, peptide, duodenal, ↑, stomach, proximal, emptying, reflux, diarrhea, intestine, resistance
Lidocaine
* It is a well-known ____ anesthetic. Lidocaine is used for ____
infiltration for ____ surgical procedures and to treat cardiac ______
* IV infusions of lidocaine improve intestinal _____ in ____
→ It reduces?
local, local, minor, arrhythmias, motility, horses, postoperative ileus
Postoperative ileus (widespread clinical problem) may be caused by?