Term
| Name the kind of cell that produces acid.... |
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Definition
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Term
| Name the cell that produces mucous and bicarbonate.... |
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Definition
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Term
| What does ECL stand for and what is their purpose? |
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Definition
| ECL stands for enterochromaffin-like cells. They have receptors for Gastrin and Acetylcholine and, upon the binding of either one of these two, produce histamine....this is a major site of Histamine release. |
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Term
| Name the two receptors that, upon activation, stimulate the Ca2+ pathway of proton-pump acid secretion. |
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Definition
| The M3 receptors (a muscarinic receptor, stimulated by acetylcholine) and the CCK2 receptor, stimulated by Gastrin. |
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Term
| Name the two receptors that, upon activation, stimulate and then inhibit the cAMP-dependent pathway of proton-pump acid secretion. |
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Definition
| The H2 receptor, stimulated by histamine (released by the ECL cells) stimulates the cAMP dependent pathway, leading to acid production via proton pumps. However, the EP3 receptor, stimulated by a prostaglandin (PGE2 or PGL2) will inhibit proton pump acid secretion. |
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Term
| Name the two receptors that, upon activation, stimulate a pathway in the epithelial cells that lead to increased mucous and bicarbonate production. |
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Definition
| The EP3 receptor, upon activation by a prostaglandin, stimulates the production of mucous and bicarbonate from the epithelial cells. Stimulation of a muscarnic receptor also does this, which can be activated by acetylcholine. So there is no confusion, let it be known that there are muscarinic receptors on the parietal cells AND the epithelial cells, so opposite processes can be going on at the same time. This is also true with the EP3 receptors. |
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Term
| Aluminum hydroxide causes , has a relatively onset of action, and tends to last a time. |
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Definition
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Term
| Magnesium hydroxide (in excess) causes , and has a relatively onset of action |
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Definition
Diarrhea; rapid You can remember this because magnesium pulls water with it, probably causing some sort of osmotic diarrhea |
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Term
| Calcium carbonate tends to be in terms of acid neutralization, causes , and causes , lots of and when used. |
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Definition
| Slow; abdominal distention; acid reflux; belching and flatulance (lol) |
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Term
| Calcium carbonate tends to be absorbed, but also cleared. This too can create a lot of |
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Definition
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Term
| When the esophageal sphincter doesn't close all the way, a person has what disease? |
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Definition
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Term
| In GERD, epithelial cells at the bottom of the esophagus become damaged.......what happens to them next? |
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Definition
| After becoming damanged, if this continues to happen, the epithelial cells will need to be replaced completely. The likelyhood of getting an esophageal tumor increases greatly, and the new cells look different and act different. There may also be strcitures, or narrowing of the esophagus |
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Term
| Severe damage caused by GERD is also referred to as..... |
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Definition
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Term
| Things that may cause the esophageal sphincter to loosen are....... |
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Definition
| Spicy foods, coffee, alcohol, and citrus fruit. |
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Term
| At night, what is one thing you could do to help prevent GERD? (This is a physical alteration) |
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Definition
| Tilt your bed slightly upwards to decrease the chance of reflux |
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Term
| In cases of Noctournal acid secretion, tend to work the best. |
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Definition
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Term
| Because of the acidity of the chyme, ulcers tend to occur where? |
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Definition
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Term
| Combination therapy using antibiotics is used to treat ulcers because an organism called is generally at fault. Where does this organism reside? |
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Definition
| Helicobacter Pylorri. This resides under the mucous layer. |
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Term
| What is the cure rate of duodenal ulcers, and how long does it take? |
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Definition
| 90%, with a 4-6 week treatment period. |
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Term
| What is the cure rate of gastric ulcers, and how long does it take? |
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Definition
| 90%, 6-8 weeks of treatment |
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Term
| Proton pump inhibitors need what to be activated? |
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Definition
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Term
| If an environment is too acidic, what will happen to the proton pump inhibitor? |
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Definition
| It will be degraded and will lose its effectiveness. |
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Term
| The PPI, after being activated by acid, will be present in the form of either or . Which one is the active form. |
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Definition
| Sulfenic Acid or Sulfenamide. Sulfenamide is the active metabolite. |
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Term
| Sulfenamide has what kind of a half-life? What about it's effects? Furthermore, how exactly does it bind to the enzyme (aka the proton pump)? |
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Definition
| Sulfenamide has a relatively short half-life. However, it has a long duration of effect. It covalently binds to the enzyme, deactivating it. |
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Term
| What are some examples of proton pump inhibitors? Also, how long does it take for someone to feel the therapeutic effects of taking a PPI? |
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Definition
| Some examples of PPI's include Esomeprazole, Lansoprazole, Omeprazole, Pantoprazole, and Rabeprazole. It takes 2-4 to fully inhibit all proton pumps. After 1 day, about 50% of proton pumps are inhibited. |
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Term
| Omeprazole will increase the effects of what medications? |
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Definition
| Warfarin, Diazepam, and Phenytoin. |
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Term
| Prolonged treatment of PPI's can actually decrease the absorption of WHAT?! |
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Definition
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Term
| What are the indications of PPI's, and what are the side-effects? |
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Definition
Indications: Nausea, abdominal pain, constipation/diarrhea Side-Effects: For GERD/Ulcers |
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Term
| List some examples of H2 antagonists |
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Definition
| Cimetidine, Ranitidine, Famotidine, Nizatidine |
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Term
| What are the first pass effects of H2 antagonists? |
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Definition
| Ranitidine, Famotidine, and Cimetidine all undergo first pass resulting in 50% bioavailability. Niziaidine has little first pass and is approximately 100% bioavailable. It is important to note that Cimetidine has a very profound effect on Cytochrome P450 and won't mix well with other medications. |
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Term
| Some H2 antagonists have strange side effects, what are they? |
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Definition
| Headache, drowsiness, fatigue, constipation, confusion, delirium, slurred speech (when given IV). Can cross the placenta, secreted in breast milk. Cimetidine can cause gynecomastia (development of breasts on men), galactorrhea (increased milk production, hopefully not in men), decreased sperm count, decreased tubular secretion of procanimide (treats cardiac arrythmias). |
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Term
| What is Misoprostol, and what are some of its characteristics? |
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Definition
| Misoprostol is a PGE2 analog. This lets it decrease the cAMP dependent pathway of proton pump stimulation, increase mucous and bicarbonate production, Increases blood flow. Foods and antacids decrease its absorption. Has short half-life, so 4 times daily dosing. Side effects are diarrhea and abdominal pain. Contraindications are pregnancy (can induce abortion) |
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Term
| What is Sucralfate, and what are some of its characteristics? |
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Definition
| Sucralfate is a sulfate and sucrose molecule (Aluminum Hydroxide?). When in an acidic environment, the molecule undergoes cross-linking, and it turns very sticky and viscous. The aluminum in the product tends to cause constipation, and can decrease the absorption of ketoconazole, tetracycline, cimetidine, and phenytoin. |
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Term
| Prokinetic agents will bind to motor neurons in the Myenteric Plexus and cause either motility or relaxation. What are the different receptors and what activity do they cause? |
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Definition
5HT3R - Activation of this causes relaxation 5HT4R - Activation of this causes contraction Dopaminergic Neuron - Activation of this causes relaxation |
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Term
| What kind of a compound is Metoclopramide and what are some of its characteristics? |
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Definition
- a Prokinetic agent that causes coordinated contractions of upper GI, antal region of stomach, upper half of small intestine. - Increases lower esophageal tone - D2 antagonist, 5HT3R antagonist, 5HT4R agonist. - Can be given orally, IV or IM. - Parkinsons like side-effects - Some anti-emetic effects |
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Term
| What is the mechanism of action of Tegaserod, and why was it pulled from the market? |
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Definition
| Tegaswerod was a 5HT4R receptor agonist, and was pulled from the market due to the potential for cardiac problems such as heart attacks and strokes. |
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Term
| What is Alosetron's mechanism of action, and what are some of its characteristics? |
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Definition
- A 5HT3R antagonist (not sure how that makes sense, if you DO know, please tell me) - Approved for diarrhea predominant IBS in females. - Relatively narrow therapeutic index - Some side effects are constipation or ischemic collitis (should discontinue immediately if either occur) - Extensively metabolized by a number of different enzymes (3A4, 2C9, 1A2) - Should not be administered with severe hepatic impairment |
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Term
| What are the similarities/differences between Ondansetron, Granisetron, Dolasetron, and Palonosetron? |
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Definition
- Anti-emetics
- All 5HT3R/Seretonin receptor antagonists - Can be used for chemo-induced, pregnancy-induced, or post-operative induced emesis. - Efficacy is the basically the same for all - Ondansetron/Granisetron metabolized by P450 - Dolasetron converted to hydroxydolasetron (active metabolite) through a carbonyl reduction. - Palonosetron has 40 hr half-life - Effects have longer half-life than medication itself - All given once a day - Side-effects include cardiac arrythmias, constipation, headache, dizziness, diarrhea |
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Term
| What kind of anti-emetic is Metoclopramide? |
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Definition
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Term
| Chlorpromazine/Promethazine are used for what? |
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Definition
Cause some movement disorders because of their anticholinergic properties. Used as anti-emetics due to their antihistamine activities, D2 antagonist as well.
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Term
| Aprepitant is what class of drug? Also, what are some of its characteristics? |
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Definition
- An NK1 Receptor Antagonist - Good with acute and delayed phase emesis - Relatively expensive, can be given orally - Because it's metabolized by 3A4, certain things can induct or inhibit the metabolism of the drug, thus increasing or decreasing the plasma concentration. - Side-effects include diarrhea, fatigue, and dizziness. |
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Term
| What class of drug is Dronabinol and what are some of its characteristics? |
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Definition
- CB1 receptor agonist - Lipophilic, so it can reach CB1 receptors in CTZ. - High volume of distribution - Highly bound to proteins - Metabolized rather extensively in liver, excretion of some metabolites in to bile. - Side-effects include tachycardia, dry mouth, increased appetite, orthostatic hypotension, euphoria (awesome), irritability if discontinued after prolonged use. - Good for chemotherapy emesis |
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Term
| What are some examples of Benzodiazepines and what is their purpose? |
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Definition
- Diazepam and Lorazepam are examples of benzodiazepines. - Purpose is to reduce anticipatory vomiting. - Must be given prior to administration of cancer agent to be effective - Properties include sedation, antianxiety effects, amnesiac effects, |
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Term
| What is an example of a glucocorticoid and what is it's purpose? |
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Definition
- Dexamethasone is an example of a glucocorticoid. It is an anti-inflammatory that has anti-emetic effects, but little is known about the mechanism. - Used in combination therapy, as it increases the efficacy of 5HT3R antagonists for prevention of acute and delayed nausea and vomiting in high-dose chemotherapy patients. |
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Term
| What are some examples of antihistamines, and how are they useful? |
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Definition
- Cyclizine, hydroxyzine, and diphenhydramine, and Scopolamine. - First three are good for motion sickness, and post-operative nausea, but not chemotherapy. - Scopolamine, on the other hand, is an anticholinergic that is good for motion sickness, but not chemotherapy emesis. |
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Term
| What is secretory diarrhea? |
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Definition
| Our GI duct epithelial layer are secretinglarge amounts of water and lectrolytes, and there is a decrease in absroption. The osmolality is about the same as plasma. For this particular type of diarrhea, this will not be affected by fasting. |
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Term
| What is osmotic diarrhea? |
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Definition
| Substances are in the GI lumen or GI tract that are not able to be absorbed, very poor absorption. As a result, these items in the lumen will exert osmotic pressure, and will bring water with it. Prevented by fasting. An example might be an individual who is lactose intolerant. |
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Term
| What is exudative diarrhea? |
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Definition
| Discharge of mucous, blood, protein. What happens is there is a basic breakdown of GI tract, and so there is an altered absorption, motility, and secretion. Types of disases that would cause this is Crohn's disease and Ulcerative Colitis. |
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Term
| A piperidine ring, present in many different compounds, can bind to different kinds of opioid receptors. These include.... |
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Definition
M-receptor - regulates intestinal motility M/Delta receptor - regulates absorption Delta receptor - regulates secretion |
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Term
| What kind of compound is loperamide, and what are its characteristics? |
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Definition
- Loperamide is an antimotility/antisecretory agent that uses its piperidine ring to bind to different receptors - Binds to M receptors to increase transit time in small intestine. - Decrease in mass movements and increase in anal sphincter tone. - Increase in colonic transit time - 40-50x more potent than morphine as anti-diarrheal. - Poor absorption through BB barrier, so low analgesic effect. - Drug has very little potential for abuse |
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Term
| What kind of drug is diphenoxylate, and what are some of its characteristics? |
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Definition
- An antisecretory/antimotility drug - Cleaved by an esterase to yield Diphenoxylic acid, the active metabolite - More potent than morphine as anti-diarrheal, has some CNS effects - Has potential for dependence - Atropine is added with (anti-cholinergic), so if people try and abuse it, they will get dry mouth, blurred vision, and urinary retention. |
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Term
| What are some characteristics of Bismuth Subsalicylate? |
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Definition
- Clay Ion, breaks down into salicylate as well as derivatives of bismuth. - Provides coating action so toxins don't interact with epithelial cells. - Can bind toxins so you won't get traveler's diarrhea - Turns tongue black or stool gray - Interferes with X-rays - Someone with Crohn's or severe collitis should not use this because a side effect is toxic megacolon (wtf?) |
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Term
| What are bulk-forming laxatives and what are some of their characteristics? |
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Definition
- Usually plant products -Want high fiber to retain water in GI to equal osmolarity - Side effects are bloating, abdominal pain, take 1-3 days to soften feces. |
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Term
| What are some examples of Osmotically active laxatives, and what are their characteristics? |
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Definition
- Saline type laxatives contain magnesium and cause retention of water in GI. - Should drink lots of water or dehydration will result. - Because of volume problems you must be weary of renal disease (problem with ions, Mg, phospate, K+) |
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Term
| What are some examples of stimulant laxatives and what are their characteristics? |
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Definition
- Cause low grade irritation and inflammation to GI tract. - We'll see increased H20/electrolyte secretion --> Peristalsis. |
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Term
| What is docusate sodium and what does it do? |
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Definition
- Is a surfactant/stool softener - Helps water penetrate into fecal matter that has been sitting in GI tract. - Tends to decrease absorption of lipid soluble vitamins. - Works relatively slowly, 1-3 days. |
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Term
| What is Mineral Oil and what are some of its characteristics? |
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Definition
- Has the relatively same mechanism of action of docusate sodium, as a stool softener or surfactant - Also interferes with absorption of lipid soluble vitamins - Shouldn't use at bedtime because it could get in respiratory tract. |
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Term
| Briefly, what is the route of adminstration of glycerin as a laxative, and how long does it take to work? |
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Definition
- Administered rectally - Takes 1-3 hours to work. |
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Term
| What kind of a laxative is lactulose, and how does it work? |
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Definition
- Lactulose is a surfactant - Non-digestable sugar, can't break it down, so it works by bringing water into the GI tract. - Increases volume and stimulates peristalsis. |
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Term
| What are 5-ASA drugs used for, and how do they work? |
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Definition
- 5-ASA drugs induce and maintain remission in ulcerative colitis and are considered to be the first-line agents for treatment of mild to moderate active ulcerative colitis; efficacy in Crohn's not well established. - Sulfasalazine contains 5-ASA bound to sulfapyridine. This reduces absorption from small intestine. In the terminal ileum and colon bactera cleave the azo bond, releasing 5-ASA, so high [Drug] are available in colon. |
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