Chapter: GI Conditions

Question 1

GASTROESOPHAGEALREFLUX
DISEASE: Background

Answer 1

Parietal cells in the stomach lining secrete hydrochloric acid (HCl) through the proton pump, stimulated by histamine, acetylcholine, and gastrin. Gastrin also aids in stomach muscle contractions for digestion. The lower esophageal sphincter (LES) normally prevents acidic gastric contents from refluxing into the esophagus. However, in gastroesophageal reflux disease (GERD), reduced LES pressure allows gastric contents to backflow into the esophagus.

Question 2

How if GERD dx?

Answer 2

Typical symptoms of GERD include heartburn, hypersalivation, and regurgitation of acidic contents. Less common symptoms like epigastric pain, cough, sore throat, hoarseness, or chest pain can mimic cardiac issues. Diagnosis relies on patient-reported symptoms, their frequency (2 or more times/ week), and risk factors, with invasive testing usually unnecessary for typical symptoms. GERD can lead to complications such as esophageal erosion, strictures, bleeding, and Barrett’s esophagus, potentially progressing to esophageal cancer. Patients with alarm symptoms or refractory GERD may require endoscopy or 24-hour esophageal pH monitoring for further evaluation.

Question 3

Key Drugs that can worsen GERD symptoms

Answer 3

Question 4

GERD Treatment Algorithm

Answer 4

Question 5

Drug TX for GERD

Antiacids: MOA

Answer 5

Antacids neutralize stomach acid, raising gastric pH quickly but providing short-term relief (30-60 minutes). They’re available OTC and suitable for mild, occasional symptoms. Patients using aspirin-containing antacids (e.g., Alka-Seltzer) should be cautious due to the risk of serious bleeding with frequent use.

Question 6

Drug TX for GERD

Antiacid: List of drugs, warnings, SEs, Notes

Answer 6

Drugs: Calcium carbonate (Tums), +Mg Mylanta, +simethicome (Maalox); MAgnesium hydroxide (milk of magnesia), Sodium bicarb/asa/actric acid (Alka-seltzer)
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Warnings: Aluminum and magnesium: can accumulate with severe renal dysfunction
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SEs: Calcium/ aluminum - consipation, magnesium - loose stool
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Notes: Calcium-containing products are pref in preggo

Question 7

Drugs for GERD

Histamine 2 Recptor Antagonists (H2RAs): MOA

Answer 7

H2RAs reversibly inhibit H2 receptors on gastric parietal cells, which decreases gastric acid secretion. They are typically used as needed for mild heartburn, although they work slower than antacids. H2RAs can also serve as maintenance therapy for GERD after initial PPI treatment, especially if there are no esophageal erosions and the patient remains symptom-free. This approach may reduce long-term side effects associated with PPIs.

Question 8

Drugs for GERD

H2RAs: List of drugs/brands, warnings, SEs, Notes

Answer 8

• Drugs: Famotidine (Pepcid) - OTC: 10-20mg; but injection: 20mg BID is RX…for famotidine if CrCl < 60 then decrease dose.
• Other drugs - Cimetidine, Nizatidine, Ranitidine
• Warning: confusion (this is usually reversible - risk factors is elderly, severely ill, renal impairment
• SEs: Cimetidine at high dose - gynecomstia, impotence…note..AOVID this drug d/t many SEs and DDI

Question 9

Drugs for GERD

Proton Pump Inhibitor (PPI): MOA

Answer 9

PPis irreversibly bind to the gastric H+/K+ -ATPase pump in parietal cells. This shuts down the proton pump and blocks gastric acid secretion . PPis are the most effective medications for GERD; an eight-week course of treatment is recommended for relief of symptoms and to heal erosions that may be present. If used long term as maintenance treatment, the lowest effective dose should be used

Question 10

Drugs for GERD

Recommended Administration of Oral PPIs: meals/ timing

Answer 10

BEFORE BREAKFAST:
- Esomeprazole (Nexium) - at least 60 mins before
- Lansoprazole (Prevacid)
- Omeprazole (Prilosec)
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Formula Specific:
- Pantoprazole (Protonix) - tablets can be taken regardless of meals, but oral suspension is 30 mins before meals
- Dexlansoprazole (Dexilant) - regardless of meals

Question 11

Drugs for GERD

PPIs: Warnings, Note

Answer 11

Warnings: C. difficile-associated diarrhea (CDAD), hypomagnesemla, vitamin B12 deficiency with prolonged use(+2 years), osteoporosis-related bone
fractures with high-doses or long-term (+1 year) use; The BEER Crietria recommend that PPIs not be used beyond 8 weeks in elderly with clear indication. PPIs may diminish the therapeutic effect of clopidogrel!!!
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Note: Pantoprazole and esomeprazole are the only PPIs available IV

Question 12

H2RA and PPI Formulations To Know

Answer 12

Question 13

Other Medication for GERD

Answer 13

Historically, drugs like misoprostol, sucralfate, and metoclopramide were used for GERD, but they’re not recommended nowadays. They can be utilized for peptic ulcer disease, with metoclopramide and erythromycin often prescribed for gastroparesis. Metoclopramide acts as a dopamine antagonist, enhancing upper GI motility, gastric emptying, and LES tone.
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Do not use Metoclopramide in patients receiving medication for parkinson disease or using antipsycho drugs

Question 14

Key Drugs With Decreased Absorption

Answer 14

Question 15

Important Note & Drug Interactions: H2RAs

Answer 15

■ Use caution with CNS depressants (especially in the
elderly) due to the risk of additive delirium, dementia and cognitive impairment. Use lower doses in patients with renal impairment.
■ Do not use famotidine with highest risk QT-prolonging drug
■ Cimetidine is a moderate inhibitor of different CYP450

Question 16

Important Note & Drug Interactions: PPIs

Answer 16

■ All PPis inhibit CYP2C19; most are weak inhibitors but omeprazole and esomeprazole are moderate inhibitors. PPis can increase the levels of citalopram, phenytoin, tacrolimus, voriconazole and warfarin.
■ Omeprazole and esomeprazole can decrease the effectiveness of clopidogrel- do nto use them together!

Question 17

Peptic Ulcer Disease: Background, What is it?/ main causes?

Answer 17

Peptic ulcer disease (PUD) involves erosions in the gastrointestinal mucosa, extending deeper than gastritis. Most occur in the duodenum, with a smaller percentage in the stomach. Common causes include H. pylori infection, NSAID use, and stress ulcers in critically ill patients/ mechanically vent patients. H. pylori (spiral shaped gram -) is the main culprit (70-95%), with less common causes including hypersecretory states like Zollinger-Ellison syndrome, viral infections, radiation therapy, and infiltrative diseases like Crohn’s Disease.

Question 18

Peptic Ulcer Disease: Symptoms

Answer 18

The main symptom of PUD is dyspepsia, which is a gastric pain that feels like gnawing or burning sensation in the upper or middle stomach. In duodenal ulcers, worsened pain typically occurs 2-3 hours after eating and is relieved by food or antacids. Gastric ulcers, often caused by NSAIDs, tend to worsen with eating.

Question 19

Peptic Ulcer Disease: Diagnostic Tests

Answer 19

For H. pylori infection, if testing is positive, treatment is recommended. Common non-invasive diagnostic tests include the urea breath test (UBT) - this test detects CO2 produced by the bacteria, and fecal antigen test. Prior to these tests, discontinuing PPIs, bismuth, and antibiotics for two weeks is advised to prevent false-negative results.

Question 20

Peptic Ulcer

Drug Treatment for H. pylori infection… the American
College of Gastroenterology (ACG) guidelines now recommend…

Answer 20

the American College of Gastroenterology (ACG) guidelines now recommend quadruple therapy first -line. The use of triple therapy firstline is only recommended if clarithromycin resistance rates are low …Do not make drug substitutions in H. pylori eradication regimens.

Question 21

Peptic Ulcers - H Pylori

H Pylori First Line Regimen Medications: what are the drugs used?

Answer 21

Question 22

Peptic Ulcer

H Pylori: Concomitant Therapy- take for 10-14 Days…Only used if clarithomycin resistance rates are low (<15%) and patient has no previous exposure to macrolide

Answer 22

Amoxiclllln 1,000 mg BID +
Clarithromycln 500 mg BID+
Metronldazole 500 mg BID +
PPI BID

Question 23

NSAID DRUG-INDUCED ULCERS: how can they cause ulcers, risk factors, prevention/ general treatment

Answer 23

NSAIDs can damage the gastric mucosa in two ways: by directly irritating the stomach lining and by inhibiting the synthesis of prostaglandins systemically through COX-1 inhibition.
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NSAIDs pose risks of elevated blood pressure and reduced renal blood flow, especially in individuals with cardiovascular or renal disease. When choosing an NSAID, consider balancing these risks with the potential for gastrointestinal (GI) ulcers and bleeding. Selective COX-2 inhibitors like celecoxib reduce GI risks but may increase cardiovascular (CV) risks compared to non-selective NSAIDs.

For patients with high GI risk, PPIs can prevent or reduce the risk of ulcers and bleeding associated with non-selective NSAIDs, though long-term risks of PPI therapy should be weighed. Misoprostol is an alternative to PPIs but may cause diarrhea, cramping, and require frequent dosing.

Combination products like naproxen/esomeprazole (Vimovo), ibuprofen/famotidine, and diclofenac/misoprostol help reduce NSAID-induced ulcers. Yosprala, combining aspirin and omeprazole, is used for secondary prevention of aspirin-associated ulcers.

Avoid non-selective NSAIDs and COX-2 selective drugs in patients at high GI and CV risk. Naproxen may be preferred in those with low-moderate GI risk and high CV risk. Treat ulcers with PPIs for eight weeks and discontinue NSAIDs. If PPIs are not suitable, consider high-dose H2RAs or sucralfate.

Question 24

NSAID DRUG-INDUCED ULCERS: Cytoprotective Drugs

Answer 24

Misoprostol is a prostaglandin E1 analog that replaces the gastro-protective prostaglandins removed by NSAIDs. Sucralfate is a sucrose-sulfate-aluminum complex and can interact with albumin and fibrinogen to form a physical barrier over an open ulcer (protects/ allow to heal)

Question 25

CONSTIPATION

Drug Categories for Treatment of Constipation

Answer 25

• Bulk-forming drugs and dietary fiber: These are usually the first-line treatment for constipation, including during pregnancy. They work by absorbing water in the intestine, adding bulk to the stool, and promoting peristalsis.
• Osmotics (e.g., polyethylene glycol): They contain large molecules that draw fluid into the bowel, distending the colon and promoting peristalsis through osmosis.
• Stimulants (e.g., senna, bisacodyl): These directly stimulate neurons in the colon, particularly helpful for patients on chronic opioids that cause constipation by reducing peristalsis. Stimulants are often used alone or in combination with stool softeners like docusate if needed.
• Stool softeners (e.g., docusate): They reduce the surface tension of stool, allowing more water and fat to mix in, thus softening the fecal mass and easing defecation. They’re commonly used by patients taking iron supplements, which can harden stools.
• Lubricants (e.g., mineral oil): These form a waterproof film around the bowel and stool, retaining moisture and facilitating easier passage during defecation.

Question 26

Key Drugs that Causes Constipation!

Answer 26

and of course antidiarrhia drug as well! (like pepto and immodium)

Question 27

Which OTC Drugs to Recommend for Constipation?

Answer 27

Question 28

Constipation

Other Drugs Used for Constipation: RX medications can be used if constipation is not relieved with OTC medications or lifestyle modifications.

Answer 28

• Chloride channel activator (e.g., lubiprostone): Increases fluid and peristalsis in the gut by acting on chloride channels.
• Guanylate cyclase C agonists (e.g., linaclotide): Boost chloride and bicarbonate secretion into the intestines, speeding up GI transit and alleviating abdominal pain.
• Peripherally-acting mu-opioid receptor antagonists (PAMORA): These medications work by antagonizing mu-opioid receptors on GI to decrease constipation
• Serotonin 5HT-4 Receptor Agonist (Eg. prucalopride) release acetlycholine which causes muscle contractions + GI motility

Question 29

Laxatives Used for Whole Bowel Irrigation

Answer 29

Laxatives formulated for bowel prep before a colonoscopy often utilize similar active ingredients as those used for constipation relief, such as PEG (polyethylene glycol). While PEG, known by the brand name MiraLax for constipation treatment, is included, formulations like GoLytely are employed for colonoscopy prep. Though generally well-tolerated, laxatives for whole bowel irrigation can induce fluid and electrolyte loss, which may pose critical risks in certain patients, particularly with products like oral sodium phosphates such as OsmoPrep. Extra caution is warranted for individuals with cardiovascular issues, renal insufficiency (causes nephro tox), or those concurrently using loop diuretics, as these conditions may exacerbate fluid loss. Similarly, NSAID use warrants attention due to its potential interaction with laxatives

Question 30

Select Drugs That Can Cause Diarrhea

Answer 30

Question 31

Diarrhea: Non Drug Treatment and Drug Treatment (general)

Answer 31

Non Drug Treatment:
Diarrhea management involves replacing fluids and electrolytes, crucial in moderate-severe cases and for vulnerable groups. Use oral rehydration solutions (ORS) like Pedialyte or Enfalyte, or Gatorade as alternatives, available over the counter.
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Drug TX:
For non-infectious diarrhea relief, short-term use of bismuth subsalicylate (Pepto-Bismol) or loperamide (Immodium - 4mg po then 2mg after next stool..max is 8mg/d but16 mg/d if under medical care) is effective. Bismuth subsalicylate acts as both an antisecretory and antimicrobial agent. Loperamide and diphenoxylate are antimotility drugs that slow intestinal movement, aiding water absorption. For IBS-D, antispasmodics like dicyclomine and, in some cases, antidepressants can help manage pain and abdominal discomfort. Eluxadoline (Viberzi) is a mu-opioid receptor agonist, unlike PAMORAs, which are mu-receptor antagonists. While PAMORAs displace opioids to alleviate constipation, eluxadoline binds to opioid receptors as an agonist to address diarrhea. It’s prescribed for IBS-D when standard treatments are ineffective

Question 32

INFLAMMATORY BOWEL DISEASE: Background (general)

Answer 32

Inflammatory bowel disease (IBD) comprises ulcerative colitis and Crohn’s disease, characterized by colon and small intestine inflammation. Symptoms include bloody diarrhea, rectal urgency, abdominal pain, fatigue, and weight loss. Flares can be triggered by infections, NSAIDs, or certain foods like fatty or gas-producing foods. Differentiating IBD from irritable bowel syndrome (IBS) is important, as they share similar symptoms but IBD involves inflammation and is more severe. Unlike IBD, IBS doesn’t cause inflammation and primarily affects bowel habits without damage to the digestive tract.

Question 33

INFLAMMATORY BOWEL DISEASE: Ulcerative Colitis vs. Crohn’s Disease

Answer 33

UC: Ulcerative colitis (UC) is inflammation of the rectum and colon with superficial ulcerations. Distal UC affects the descending colon and rectum and can be treated with topical medications. Proctitis refers to inflammation limited to the rectum. Symptoms range from mild to severe, with severe cases involving >6 bloody stools daily, fever, anemia, and elevated ESR. Fulminant UC is severe, with >10 stools daily
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CD: Crohn’s disease (CD) involves deep, transmural inflammation affecting various parts of the GI tract, commonly the ileum and colon. It can lead to strictures and fistulas. Symptoms include chronic diarrhea, abdominal pain, and weight loss.

Question 34

Inflammatory Bowel Disease: Lifestyle Management, supportive care/ natural products

Answer 34

Patients with IBD should adjust their diet to minimize triggers for flares, including smaller, low-fat, dairy-free meals and ample water intake. They should avoid alcohol, caffeine, and carbonated drinks. Sorbitol and lactose. Antidiarrheals and antispasmodics like dicyclomine can help manage symptoms cautiously, under medical supervision. Vitamin supplements can prevent deficiencies due to malabsorption. Probiotics like Lactobacillus or Bifidobacterium infantis may alleviate symptoms, while fish oils with omega-3 fatty acids could help fight inflammation, though evidence is limited.

Question 35

General Drug Treatment options for UC mild? mod-severe?

Answer 35

Treatments for IBD focus on inducing and maintaining remission. Short courses of oral or IV steroids are common for acute exacerbations in both ulcerative colitis (UC) and Crohn’s disease (CD), but not for maintenance.
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Aminosalicylates, containing 5-aminosalicylic acid (5-ASA), are used for maintenance in distal UC or mild extensive disease.
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Moderate to severe UC cases extending beyond the colon and rectum may require other immunosuppressive medications like thiopurines, anti-tumor necrosis factor (TNF) drugs, tofacitinib, or cyclosporine.

Question 36

General Drug Treatment options for CD: mild? mod-severe?

Answer 36

For mild Crohn’s disease (CD) affecting the ileum and proximal colon, oral budesonide is preferred.
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In moderate to severe cases, immunosuppressive drugs like thiopurines, anti-TNF agents, methotrexate, and IL receptor antagonists can be used. Steroids may be necessary for severe CD. Integrin receptor antagonists like vedolizumab are used for CD that doesn’t respond to other treatments or is steroid-dependent.

Question 37

Study Tip Gal!

MAINTENANCE OF REMISSION: COMPARISON OF COMMON CD AND UC TREATMENT…Focus on Crohn’s Disease: Mild, mod-severe, refractory

Answer 37

Question 38

hStudy Tip Gal!

MAINTENANCE OF REMISSION: COMPARISON OF COMMON CD AND UC TREATMENT…Focus on Ulcerative Colitis: Mild, mod-severe, refractory

Answer 38

Question 39

Steroid used for IBD: list the oral/ rectal options any SEs (long/short term) and note

Answer 39

Oral Steroids
- Prednisone, Budesonide (Entocort)
- Short term SE: increase appetite, weight gain, insomnia, emotional instability
- Long term SE: Cushing/ Adrenal suppression, increase BG/BP
- Note: avoid long term use, if used longer than 2 weeks, must taper assess bone density in long term use
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Rectal Steroids
- Hydrocortisone and Budesonide
- Notes: Rectal steroid is for UC ONLY!!
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General Note: Avoid Budesonide with inhibitor of CYp3A4 including grapefruit!!!

Question 40

Drugs for IBD - UC

AMINOSALICYLATES: MOA, List of drugs, and any relevant notes

Answer 40

MOA: Aminosalicylates are used to treat UC by reducing inflammation in the gastrointestinal tract, though the exact mechanism isn’t fully understood. Mesalamine (Pentasa) or (suppository - Canasa) is the primary choice in the U.S., available in oral and rectal forms and well tolerated. Other aminosalicylates (sulfasalazine, balsalazide, olsalazine) are only available orally and must convert to mesalamine to work. Sulfasalazine, less common due to side effects from its sulfapyridine component, is an example.
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Note - do not use if salicylate allergies

Question 41

Drug for IBD

Thiopurines: Indication, Drug, any important notes

Answer 41

Though lacking FDA approval for IBD, thiopurines are recommended in guidelines for inducing and maintaining remission, often alongside other medications.
- Azathioprine and Mercaptopurine
- Notes: Hematologic toxicities (e.g., leukopenia, thrombocytopenia, anemia); patients with a genetic deficiency of thiopurine methyltransferase (TPMT) are at increased risk for myelosuppression

Question 42

Motion Sickness: Nondrug treatment vs. Drug treatment

Answer 42

Non Drugs: Some patients find relief from nausea using wrist bands like Sea-Band, which target an acupuncture point on the inside of the wrist. Ginger, is a common remedy for nausea, especially in motion sickness. Peppermint may also help. Ultimately, stopping motion is the most effective way to alleviate motion sickness
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Drugs: antihistamines and anticholinergics are recommended.
- Scopolamine (Transderm Scop), the most prescribed anticholinergic - no more effective than OTC tho but it lasts three days when applied behind the ear.
- Antihistamines like cyclizine, diphenhydramine, dimenhydrinate, and meclizine are used for motion sickness, but they cause drowsiness and should be taken 30-60 minutes before needed.
- Promethazine, only available by prescription, carries risks of respiratory depression and should not be used in children under 2 years old.
- ALL ANTIHISTAMINE HAVE ANTICHOLINERGIC EFFECTS SIMILAR TO SCOPOLAMINE
- Metoclopramide and ondansetron (5HT-3 antagonists) are ineffective for motion sickness!!!

Question 43

Scopolamine (Transderm Scop) Patch: How to use?/ Special consideration/ notes

Answer 43

Note: Aside from antiholinergic side effects (dry) and CNS depression it can also cause stinging of eye/ diulation and increase risk of IOP…This patch needs to be removed prior to MRI (contains metal)