GI Drugs p1 Flashcards
Signs of GI disease (6)
- Vomiting
- Nausea (decreased appetite)
- Diarrhea
- Acid reflux
- Motility abnormality
- Gas accumulation
Label the parts of the stomach (either A or B)
-Fundus -Cardia -Duodenum
-Esophagus -Pyloric antrum -Body
-Pylorus
The ___ & ___ relax with swallowing of food. ___ of stomach contracts to help mix food. ___ ___ increases contractions in response to swallow. It stimulates ___, grinding, and propulsive contractions that move food towards the ___.
___ muscle in the stomach wall responds to hormones, peptides, & ___ system controls.
- Fundus & body
- Body
- Pyloric antrum
- Mixing
- Pylorus
- Smooth
- Nervous system
- Parasympathetic nervous system causes fundus to…
- Sympathetic stimulation can cause a decrease in…
- Relax & increases contractions in the antrum.
- Motility - gastric atony
How does the vomiting reflex work? (3)
- Chemoreceptor Trigger Zone (CTZ) & Vomiting Center (VC) are regions within the brain.
- When they are stimulated, these regions initiate the vomiting reflex.
- Different causes of nausea & vomiting stim the regions in different ways.
Triggers of vomiting (5)
- Nerve stimulation in the emetic center
- Chemical stimulation in CTZ
- Distension or irritation of any part of the GI tract, peritoneum, kidneys, gallbladder, or uterus.
- Nerve stimulation in the inner ear
- Brain swelling or emotional stimuli
What are emetics? How are they used?
- Drugs that induce vomiting
- Used in Tx for poisoning & drug overdose
Vomiting should not be induced if/when… (4)
- Caustic substances have been ingested.
- Animal has decreased consciousness.
- Esophagus or stomach is at risk for rupture.
- In species that don’t vomit! (horse, rabbit, rodents)
Emetics examples as…
1. Centrally acting (2)
2. Locally acting (2)
- Central
- Apomorphine
- Xylazine - Local
- H2O2 3%
- Concentrated salt solutions
Emetics when centrally acting are working on the…
When locally acting they are…
- CRTZ
- Irritating the GI tract 3
What are Antiemetics? How are they administered?
- Drugs that control vomiting that help alleviate discomfort & help control electrolyte balance.
- Administered parentally (mostly) since the Pt may vomit the antiemetic before it can be absorbed thru the GI tract.
Examples of antiemetics (6)
Name three
- Phenothiazine derivatives
- Antihistamines
- Anticholinergics
- Prokinetic drugs
- Serotonin receptor antagonists
- NK-1 Receptor antagonists
Phenothiazine derivatives (antiemetic)
1. How they work/What they do
2. Side effects (3)
3. Examples (4)
- Inhibit dopamine in the CTZ, thus decreasing the stim to vomit.
- Side effects
- Hypotension
- Sedation
- Dehydration - Examples
- Acepromazine
- Chlorpromazine** (strongest antiemetic affects)
- Prochlorperazine
- Perphenazine
Antihistamines (antiemetics)
1. How they work/What they do
2. Side effect
3. Examples (2)
- Controls vomiting when the vomiting is due to motion sickness, vaccines reactions, or inner ear problems.
- Side effect is sedation
- Examples
- Dimenhydrinate (Dramamine)
- Diphenhydramine (Benadryl)
Anticholinergics (antiemetics)
1. How they work/What they do
2. Side effects (4)
3. Examples (3)
- Block acetylcholine peripherally, which decreases intestinal motility & secretions.
- May decrease gastric emptying (may increase tendency to vomit) (not commonly used). - Side effects
- Dry mouth
- Constipation
- Urinary retention
- Tachycardia - Examples
- Aminopentamide
- Atropine
- Propantheline
Prokinetic drugs (antiemetics)
1. How they work/What they do
2. Do not use in patients with… (3)
3. Examples (2)
- Works peripherally by speeding gastric emptying, strengthening cardiac sphincter tone, & increasing the force of gastric contractions.
- Don’t use in Pt with:
- GI obstructions
- GI perforation
- GI hemorrhage - Examples
- Metoclopramide
- Cisapride
Serotonin Receptor Antagonists (antiemetics)
1. How they work/What they do
2. Examples (2)
- Work selectively on 5-HY3 receptors, which are located peripherally & centrally.
- Work on the theory that some chemicals cause vomiting because they increase serotonin release from small intestinal cells. - Examples
- Ondansetron (Zofran)
- Dolasetron
Cerenia (maropitant citrate) (antiemetic)
What is it/How does it work?
Maropitant is a neurokinin (NK1) receptor antagonist that blocks the pharmacological action of substance P in the CNS
Gastrin
1. Produced by the…
2. Increases production of…
3. Inhibits…
- G cells in the antrum of the stomach in response to protein, stretch or PNS.
- Hydrochloric acid
- Muscle activity of the fundus
- Causes relaxation
Mediator of GI function (2)
- Prostaglandins
- Gastrin
Prostaglandins
1. Increase… (3)
2. Decrease… (1)
- Increase…
- Fluids & mucous in GI
- Bicarbonate buffers
- Blood flow to region - Decrease…
- Gastric acid
Hydrochloric Acid:
Hydrogen & chloride ions secreted by ___ cells in the gastric glands.
They combine in the ___ to produce more hydrochloric acid.
Receptors on parietal cells for ___, ___, & ___ involved in regulation of H+ & Cl- secretion. Selectively blocking one of these receptors ___ the production of stomach acid.
- Parietal cells
- Stomach
- Gastrin, histamine, & acetylcholine
- Decreases
Appetite stimulants (6)
- Diazepam
- Cats IV - Cyproheptadene
- Antihistamine can be given on a chronic basis - Mirtazapine
- Antidepressant in people, increases serotonin levels - Anabolic steriods
- Testosterone - Ghrelin agonists
- Entyce for dogs - CBD from hemp
Antifoaming (anti-bloat) drugs reduce or prevent formation of ___. These drugs make it less ___, breaking it up to promote ___ release through ___.
It should be administered as solutions by a stomach ___ directly into the __stomach.
- Foam
- Stable
- Gas
- Belching
- Tube
- Forestomach
Examples of antifoaming drugs (3)
- Poloxalene
- Polymerized methyl silicone
- DSS
