Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Pharmocology > Gastrointestinal Pharmacology > Flashcards

Gastrointestinal Pharmacology Flashcards

1
Q

What is the purpose of neurokinin (aka substance P)?

A

Antiemetic
neurotransmitter affects several physiological processes including:
- vascular tone/permeability
-mucus production/bronchial tone in respiratory system
-heart rate
some CNS activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Maripotant

A

newer class of antiemetics, has become first line for dogs, cats
• may have visceral analgesic properties (neurokinin is also a pain neurotransmitter)
effective for motion sickness, but higher doses required
• hepatic clearance, dose reduction in hepatic impairment
• oral, injectable preparations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the adverse effects of maripotant?

A

ADVERSE EFFECTS: Generally well-tolerated. Paradoxical emesis at high (motion sickness)
doses-better if given with food. Swelling/pain at sub-q injection site: refrigerate prior to injection
and inject cold drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which animals can NOT vomit?

A

horses, rodents and rabbits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some examples of afferent neuronal stimulations that cause vomiting via the neuronal pathway?

A
  • mechanoreceptors in pharynx
  • tension receptors/chemoreceptors in gestural an duodenal mucosa
  • direct stimulation of GI
  • Vestibular system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the humoral afferent neuronal signals?

A

CRTZ- senses toxins/drugs in blood–>emetic center in brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Ondansetron

A

5-HT3 antagonist (serotonin)
•particularly useful in chemotherapy, GI tract injury (serotonin released by GI damage from chemotherapy & GI tract injury)
• primarily hepatic clearance, oral absorption is low in dogs and may be ineffective
•oral, injectable preparations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are Ondasetrons adverse effects?

A

ADVERSE EFFECTS:
◦ generally well-tolerated
◦ may cause sedation in dogs with variant mdr1 gene/protein
◦ potential for CNS signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Metoclopramide

A
  • primarily used as an upper GI prokinetic, may sensitize GI tract to PNS cholinergic stimulation but has some antiemetic effect
  • antiemetic effect greater in dogs, relatively weak in cats
  • hepatic clearance
  • oral, injectable preparations

**prokinetic effects primarily on upper GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Metclopramide Adverse effects?

A

ADVERSE EFFECTS:
◦ dopamine & serotonin antagonist in CNS –> sedation, agitation, behavioral changes,
vocalization, tremors, extrapyrimidal signs (movement disorders: circling, restlessness,
repetitive movement)
◦ prokinetic effects contraindicate use in GI obstruction, perforation
◦ abdominal pain in horses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Prochlorperazine

A
  • less sedative action than other phenothiazines, e.g. acepromazine (a phenothiazine sedative)
  • primarily hepatic clearance
  • oral, injectable preparations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do Phenothiazines work?

A

Phenothiazines have effects at several receptor types. They are antagonists at alpha-1 and alpha-2
adrenergic receptors, dopamine (D2) receptors, H1 and H2 histamine receptors, and at muscarinic
cholinergic receptors. At typical doses their effect is focused on the CRTZ, and at higher doses at the
vomiting center

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do NK-1 antagonists work?

A

Neurokinin (also called Substance P) is a neurotransmitter impacting several physiological processes,
including vascular tone/permeability, mucus production/bronchial tone in the respiratory system, heart
rate, and some CNS activity. In vomiting it is a key neurotransmitter in the vomiting center, and initiates
vomiting stimulated by both humoral and neuronal pathways acting at the NK-1 receptor.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do antihistamines work?

A 
Histamine receptors (both H1 and H2) involved in CRTZ, and in neuronal pathway from vestibular
apparatus (hence use in motion sickness). These pathways are important in emesis in humans, less
important in dogs, and relatively unimportant in cats.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Diphenhydramine

A

•first generation H1 antagonist
• ineffective in cats, effectiveness in dogs inconsistent
• low bioavailability in dogs (< 10%)
Adverse Effects
◦ CNS depression
◦ anticholinergic effects (xerostoma, ileus, constipation, urinary retention)
• oral, injectable preparations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Apomorphine

A
  • dopamine agonist in CRTZ, a study reports vomiting in 94% of treated dogs – don’t be fooled by the name, not an opioid!
  • poorly effective in cats
  • contraindicated in species that can not vomit
  • oral, injectable preparations, tablets can be placed, or dissolved and placed, subconjunctivally
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are apomorphines adverse effects?

A

ADVERSE EFFECTS
◦ nausea, lethargy, salivation
◦ hypotension, CNS/respiratory depression with overdose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the MOA of Hydrogen Peroxide?

A

gastric irritant, stimulates vomiting through neuronal afferents from stomach
**not preferred if apomorphine available, but if the benefits of client administration outweigh the risks it is the most available at-home canine emetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the adverse effects of hydrogen peroxide?

A

ADVERSE EFFECTS
◦ documented gastric lesions from 3% solution, resolved by 14 days
◦ potential for serious tissue damage if solutions > 3% used
◦ potential for hemorrhagic gastritis/esophagitis in cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What class of drug is xylazine?

A

sedative/anesthetic, alpha-2 adrenergic agonist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the MOA of xylazine?

A

unknown, alpha-2 agonists currently most reliable emetic in cats, exact mechanism unclear, study reported emesis in ~50% of treated cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the adverse effects of xylazine administration?

A 
ADVERSE EFFECTS
◦ muscle tremors
◦ hypotension
◦ bradycardia
◦ A-V block
◦ sedation
◦ respiratory depression
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Xylazine is oral or injectable?

A

injectable

24
Q

What class is erythromycin? MOA?

A

macrolide antibiotic, prokinetic mechanism unclear, likely involves stimulation of serotonin and/or motilin receptor

25
Q

What are some adverse effects to erytromyacin?

A

ADVERSE EFFECTS
◦ GI effects
◦ vomiting/diarrhea
◦ inappetence

26
Q

Ranitidine

A

Presented in Antiulcer Drugs
• prokinetic effects on GI motility (particularly gastric)
• mechanism of action is inhibition of acetylcholinesterase, increasing PNS response

27
Q

What is the class and function of omeprazole?

A

PPI, pro-drug in blood–>activated by high PH in parietal cells (so administer 30-60 min prior to feeding), maximal effect 2-4 days therapy–>prevents secretion of H+ ions
-primarily oral, pantoprazole can be given IV

plumbs: binds irreversibly at the secretory surface of parietal cells to the enzyme H+/K+ ATPase, where it inhibits the transport of hydrogen ions into the stomach by 90% to 99%. Omeprazole can reduce acid secretion during both basal and stimulated conditions.

28
Q

What are some adverse effects of Omeprazole?

A

ADVERSE EFFECTS
◦ Generally well-tolerated in dogs, cats
◦ diarrhea (dogs)

29
Q

What is the class of Famotidine? MOA?

A
  • Histamine H2 antagonist, less efficacious than PPIs, but substantially fewer DDIs
  • IV, oral preparations
30
Q

What are the adverse effects of famotidine?

A

ADVERSE EFFECTS
◦ bradycardia from rapid IV injection
◦ rare reports of hemolysis when given IV to cats, may be avoided by slow (5min) administration.

31
Q

What is the class of sucralfate? MOA?

A

GI-protectant–>Reacts with gastric HCl to form polymeric layer over gastric mucosa
• Widely used, but weak research basis for effectiveness
• Believed to provide local effect, perhaps increasing protective prostaglandin (E2, I2) levels
• well tolerated
◦ oral prep

32
Q

What are some adverse effects of sucralfate?

A

◦constipation

◦ contains aluminum, caution with renal impairment

33
Q

Misoprostol

A

synthetic prostaglandin (PGE1) analogue (one of the PGs that supports gastric mucosal barrier
function)
• prevents ulcer formation when concurrently administered with NSAIDS
◦ importantly, this effect has only been demonstrated for aspirin
◦ does not appear to prevent glucocorticoid-induced ulcers
◦ not recommended for first-line treatment of existing ulcers
• ADVERSE EFFECTS
◦ GI pain, vomiting/diarrhea
◦ uterine contractions/vaginal bleeding in dogs
◦ abortifacient (has been intentionally used for this)
◦ may diminish pH-increasing effect of omeprazole
• Oral preparations

34
Q

Stimulant (Irritant) Laxatives

A

The exact mechanism of action for this group of laxatives is uncertain, but they appear to cause
electrolyte loss by inhibiting Na+/K+-ATPase in the intestine and increasing electrolyte loss through
intestinal tight junctions. These drugs have an onset of action of within 6–to 8–hours. They can have
potent effects and excessive fluid and electrolyte loss can result from overdoses.
• ADVERSE EFFECTS: damage to enterocytes from chronic use and abuse
• Prototype anthraquinone drugs
◦ bisacodyl (Dulcolax)
◦ senna (Senokot)
◦ cascara sagrada (Nature’s Remedy)

35
Q

Hyperosmotic Cathartics (Saline Cathartics)

A

The saline cathartics are non-absorbed electrolytes that draw fluid into the bowel via osmosis. These
are the most rapidly acting of the cathartics, with onset of action in 1– to 3–hours. The fluid content of
the stool increases, which causes intestinal distention and promotes increased normal peristalsis. These
have been some of the most commonly used cathartics in veterinary medicine. Most often they are
dissolved in an aqueous solution (water) and administered via gastric gavage (stomach tube). These
drugs have been used to prepare animals for an endoscopic procedure (bowel cleansing) or for
cathartic treatment of poisoning. They are relatively safe drugs, but overdoses can cause fluid loss in a
patient. Examples include:
• magnesium sulfate
• lactulose
• polyethylene glycol

36
Q

Hydrophilic Colloids (Bulk Laxatives)

A

These agents are mostly natural products and dietary plant fibers. They are composed of nonabsorbed synthetic or natural polysaccharide and cellulose derivatives. These fibers are resistant to
digestion and attract water into the intestine. By imbibing water, they increase the mass of
nondigestible material in the bowel and motility is increased through the stimulation of
mechanoreceptors. They are more slowly acting than other drugs with an onset of action of 24 hours, or
longer. They are relatively safe drugs with few side effects. Examples include:
psyllium (Metamucil)
• canned pumpkin
• carboxymethylcellulose

37
Q

Lubricant Laxatives (Mineral Oil and Liquid Petrolatum)

A

The lubricants act by coating the surface of the stool with a water-immiscible film and increasing the
water content of the stool. They also produce a lubricant action to ease passage of the stool. Lubricant
laxatives usually contain mineral oil (liquid petrolatum) or white petrolatum. Many of the
nonprescription products contain white petrolatum (Vaseline) as their ingredient. Administration of
glycerin also has been used as a lubricant laxative. The lubricant laxatives are relatively safe because
they are absorbed poorly from the GI tract. If they enter the respiratory tract (misadministration,
aspiration) they can incite a severe inflammatory response. Chronic use may decrease the intestinal
absorption of fat-soluble vitamins.
• Use in large animals: These drugs, particularly mineral oil, are popular for several nonspecific GI
problems in horses and cattle.
• Use in small animals: Products such as Laxatone, Felaxin, and Kat-a-Lax are promoted for
increasing the passage of trichobezoars (hair balls) in cats. These products contain white
petrolatum (Vaseline) as their active ingredient with additional flavorings.

38
Q

Diphenoxylate/Loperamide

A

opioid antidiarrheal–>Antidiarrheal opioids act at mu receptors, increase segmental contractions, prolong transit time,
allowing more fluid resorption
• Avoid use in cats: may manifest excitatory behavior
• ADVERSE EFFECTS: overdoses can produce CNS depression, respiratory depression, coma,
death
◦ Diphenoxylate: well-tolerated. Constipation, bloating can occur, managed with laxatives
◦ diphenoxylate is poorly active in CNS, so limited CNS effects at recommended dose
◦ Loperamide: well tolerated. Constipation can occur, managed with laxatives
◦ loperamide IS active in CNS, but it is excluded from CNS by mdr1 pump, thus mdr1 variant
dogs can manifest opioid overdose signs
• oral preparations

39
Q

Bismuth Subsalicylate

A

Multiple beneficial effects, anti-inflammatory, antimicrobial, blocks some effects of enterotoxins
• well-tolerated, overdose can cause salicylate toxicity, especially in cats
• oral preparations

40
Q

Sulfasalazine and 5-aminosalacylic acid (5-ASA)

A

Sulfasalazine: combination sulfonamide and 5-aminosalicylic acid, colonic bacteria required to cleave to active component drugs, thus only active in large bowel pathology.
5-ASA: similar beneficial effects as sulfasalazine without the adverse effects of the sulfonamide.
• Used in treating inflammatory bowel disease, esp. after dietary modification unsuccessful
• ADVERSE EFFECTS:
◦ keratoconjunctivitis sicca (KCS) (with sulfasalazine, less so with 5-ASA)
◦ sulfonamide-associated hypersensitivity, hypothyroidism (with sulfasalazine)
• oral preparations

41
Q

What class of drug is Mirtazapine? MOA?

A

serotonin antagonist, tricyclic antidepressant–>appetite stimulant, esp in cats, oral, transdermal preparations (cats)

42
Q

What are the adverse effects of mirtazapine?

A

ADVERSE EFFECTS
◦ well-tolerated at recommended dose
◦ in cats, esp. at high doses, vocalization, agitation, vomiting, ataxia
◦ in cats with transdermal preparation, erythema/crusting at application site

43
Q

What class of drug is caromorelin? MOA?

A

•ghrelin receptor agonist, acting on hypothalamus increasing appetite and growth hormone release
• approved for appetite stimulation in dogs. Scant data available in cats.
oral preparations

44
Q

What are the adverse effects of capromorelin?

A

ADVERSE EFFECTS
◦ vomiting/diarrhea, polydipsia, hypersalivation
◦ unpredictable lack of response in some patients

45
Q

Sulfadimethoxine

A

sulfonamide antibiotic
• Inhibits metabolism that produces dihydrofolic acid in target organism. Dihydrofolic acid is a
key intermediate in the synthesis of nucleic acids.
• ADVERSE EFFECTS
◦ sulfa hypersensitivity (KCS, autoimmunity in various organ systems)
◦ crystalluria (especially high doses)
◦ hypothyroidism (especially high doses, extended duration)
• oral, injectable preparations

46
Q

What class of drug is Ronidazole? MOA?

A

-nitroimidazole antibiotic (same class as metronidazole)
-Bioactivated by anaerobic bacteria/protozoa (only active in anaerobic environments)
• only available compounded, oral, injectable

47
Q

What are the adverse effects of Ronidazole?

A

ADVERSE EFFECTS
◦ reversible neurotoxicity (tremor, lethargy, nystagmus, agitation)
◦ inappetence, vomiting
◦ bitter tasting, administer in capsule form

48
Q

What is the class of drug of Metronidazole? MOA?

A

nitroimidazole antibiotic
-Bioactivated by anaerobic bacteria/protozoa (only active in anaerobic environments)
• oral, injectable

49
Q

What are the adverse effects of Metronidazole?

A

ADVERSE EFFECTS
◦ reversible neurotoxicity (tremor, lethargy, nystagmus, agitation)
◦ inappetence, vomiting
◦ bitter tasting, in cats, metronidazole benzoate (compounded) more palatable

50
Q

What drug class is Pyrantel in? MOA?

A

-pyrimidine anthelmintic
-Acts as an agonist at nicotinic cholinergic receptors. These receptors are located at the neuromuscular junction of the parasite. Pyrantel produces constant receptor activation, ultimately resulting in impairment of muscle triggering by receptor activation. The resulting muscle paralysis leads to the death of the nematode.
• Poorly absorbed from GI tract (not a problem for intestinal nematode infestation!)
-oral preparations

51
Q

What are the adverse effects of Pyrantel?

A

ADVERSE EFFECTS
◦ adverse effects very unusual
◦ inappetence, vomiting, diarrhea (may also be related to parasite die-off)

52
Q

What is the drug class of Praziquantel? MOA?

A

-anticestocodal anthelmintic
-Unclear, causes dramatic ionic flux of Na+, K+, Ca++ in parasite, well tolerated
-oral, injectable preparations
• many formulations in combination products, e.g., Drontal-Plus (praziquantel/pyrantel/febantel)
to increase anti-parasitic spectrum of activity

53
Q

What re the adverse effects of Praziquantel?

A

ADVERSE EFFECTS
◦ inappetence
◦ vomiting
◦ diarrhea lethargy

54
Q

What class is Fenbendazole in? MOA?

A
  • benzimidazole anthelmintic
  • The benzimidazole class of antiparasitics works by disrupting the constant assembly and disassembly of intracellular microtubules, part of the dynamic cellular framework that has multiple functions, including organizing chromosomes during cell division
  • well tolerated
  • oral prep
55
Q

What are the adverse effects of Fenbendazole?

A

ADVERSE EFFECTS
◦ salivation
◦ vomiting
◦ diarrhea (infrequent)

Pharmocology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions