Gastrointestinal pharmacology Flashcards
(33 cards)
Which of the following is not a drug acting on the GI system?
- Antidiarrheals
- Cathartics
- Emetics
- Prokinetics
- Anti-ulcer medications
- Antiemetic
- All of the above
- All of the above
What are stimulants of appetits?
- Norepinephrine (alpha-2)
- Dopamine (D1 receptors)
- GABA (by inhibiting the satiety center)
What inhibits appetite?
Serotonin (5-HT1)
Which drugs are most commonly used as appetite stimulants to “treat” anorexia/hyporexia?
GABA agonists
- Benzodiazepines (Diazepam, Midazolam)
- Propofol
Which drugs are serotonin (5-HT) antagonists to “treat” anorexia/hyporexia in cats and dogs?
Both are human label
- Cyproheptadine in cats
- Mirtazapine in dogs
Besides GABA agonists and Serotonin (5-HT) antagonists, which drugs have appetite stimulating effects to “treat” anorexia/hyporexia?
- Glucocorticoids- Prednisone (good for inflammatory bowel disease)
- B-vitamins
- Megestrol acetate
- Anabolic steroids- Stanozolol
Which GABA agonist appetite stimulant is more effective in cats than it is in dogs and is generally useful for short term only?
Benzodiazepines (Diazepam, Midazolam)
- Stimulating GABA inhibits satiety center to increase appetite
- Most common side effect is sedation
Which GABA agonist appetite stimulant has a very short-term (15 min) effect and should be used with caution in cats because it may cause Heinz body anemia if used for more than 5 days?
Propofol
- Effect is seen at sub-hypnotic doses
Which appetite stimulant more commonly used in dogs than in cats, blocks both 5-HT1 and 5-HT2 receptors?
Mirtazapine
- Serotonin (5-HT) antagonist
- Also increases NE centrally
- Cats dosed q1-3days
Which oral appetite stimulant is more effective in cats than it is in dogs and blocks 5-HT1 receptors?
Cyproheptadine
- Serotonin (5-HT1) antagonist
- Generally 2-3 days to see a response
- Most common side effect is sedation
T or F. The emetic center and CRTZ (chemoreceptors) are both outside of the BBB.
False. The emetic center is inside the BBB while CRTZ is outside of the BBB
What is a peripherally acting emetic that is used for immediate treatment (typically at-home by client) by causing direct irritation of the oropharynx/GI lining, but should NOT be used in cats (hemorrhagic gastritis)?
Hydrogen peroxide 3%
- Don’t use other peripheral antiemetics (more risk):
- Syrup of ipecac
- Saline solution
- Dilute dish soap
Which centrally acting emetic can be given by all routes (including conjunctival sac) most effectively in dogs and stimulates dopamine (D2) receptors?
Apomorphine
- Opioid
- Cat efficacy only 10%
- Overdose can cause respiratory depression- reverse with naloxone (note that IT WON’T REVERSE THE EMETIC EFFECT!)
Which centrally acting emetic is more effective in cats than it is in dogs because it is an alpha-2 agonists and cats have more alpha-2 receptors and fewer D2 receptors?
Xylazine or Dexmedetomidie (Dexdomitor)
[FYI] Which oral or injectable anti-emetic is a dopamine (D2) antagonist?
- Metoclopramide
- Maropitant (Cerenia)
- Ondansetron, (dolasetron)
- Metoclopramide
- Intermittent SC or IV CRI
- Also blocks 5-HT3 receptors at higher doses
- Also a prokinetic
- Antagonizes apomorphine induced emesis
[FYI] Which injectable anti-emetic (oral available) is more potent than metoclopramide and is a serotonin (5-HT3) antagonist?
- Metoclopramide
- Maropitant (Cerenia)
- Ondansetron, (dolasetron)
- Ondansetron, (dolasetron)
- Acts on serotonin receptors centrally and peripherally
- Initially used for chemotherapy related nausea
- $$$
- Usually given by injection
[FYI] Which anti-emetic for dogs (oral or SC) and cats (SC) is a neurokinin inhibitor (NK1) receptor antagonist?
- Metoclopramide
- Maropitant (Cerenia)
- Ondansetron, (dolasetron)
- Maropitant citrate (Cerenia)
- Labeled for prevention of motion sickness in dogs (oral)
- Antagonists at NK1 receptors which blocks substance P and reduces it’s contribution to vomiting
- Works at the level of the emetic center and the CRTZ
- Substance P is involved in integration of pain, stress, anxiety, and vomiting
- Injection stings!!: Reduce sting by refrigerating or diluting to administer
[FYI] Which drug is used to antagonize apomorphine induced emesis?
Metoclopramide (Reglan)!
[FYI] Which of the following is a common oral or injectable anti-ulcer drug that reduces gastric acid by blocking antihistamine H2?
- Misoprostol
- Omeprazole
- Famotidine
- Sucralfate
- Famotidine “Pepcid” (Cimetidine, Ranitidine, Nizatidine)
- Also inhibits pepsin secretion
- Competitive inhibition of H2 receptors
- Cimetidine is an inhibitor of hepatic microsomal enzymes
- Famotidine is more potent and longer lasting than cimetidine (also has far fewer drug interactions)
- Ranitidine (Zantac) and Nizatidine have similar potency and duration to famotidine; also have some prokinetic activity (esp. in dogs)
[FYI] Which of the following is a common oral anti-ulcer drug that reduces gastric acid by inhibiting proton pumps?
- Misoprostol
- Omeprazole
- Famotidine
- Sucralfate
- Omeprazole “Prilosec” (Pantoprazole and Lansoprazole are injectables)
- Irreversibly inhibit H+/K+/ATPase proton pump resulting in decreased hydrochloric acid production
- More potent than H2 blocker class
- Raise gastric pH
- Labeled equine product
[FYI] Which of the following is an oral prostaglandin E1 analog that is used treat NSAID-induced gastric ulcers?
- Misoprostol
- Omeprazole
- Famotidine
- Sucralfate
- Misoprostol
- Increases mucus and sodium bicarbonate secretion, stimulates epithelialization of the mucosa and mucosal blood flow resulting in ulcer healing (COX-1)
- Mild direct decrease in acid production
- Caution: abortifacient, can stimulate uterine contraction and cause diarrhea
[FYI] What are some oral antacids used to treat/prevent ulcers by reducing gastric acid?
Aluminum, magnesium and calcium salts (Tums)
- Chemically neutralize hydrochloric acid
- Aluminum hydroxide also inactivates pepsin and binds to bile salts, may stimulate PGs
- Bind phosphorous in the gut and can also cause constipation
[FYI] Which of the following is a sucrose-aluminum compound given orally which acts as a gastroprotectant used to treat or prevent ulcers?
- Misoprostol
- Omeprazole
- Famotidine
- Sucralfate
- Sucralfate
- Binds to the ulcer site and protects it against acid, pepsid and bile (requires an acidic environment to bind to mucosa)
- May also stimulate protective PGs and antioxidants and increase mucosal blood flow
- Poorly absorbed (acts locally) and has few side effects; constipation sometimes seen and binds to other drugs
[FYI] The time it takes for material to get from point A to B within the GIT
Transit time
