Pharm: L15: GI Drugs

Question 1

Acid Neutralizing Agents

1. Calcium Carbonate

ANTACIDS

2. Can alter Absorption or Excretion of Drugs
   a. Complexes 7 drugs?
   b. Absorption decreased with what 3 drugs?
   c. Elimination Increased with what 2 drugs?
   d. Increase Absorption of what 3 drugs?

Answer 1

1. Common
2. a. Antibiotics, Iron, Isoniazid, Ketoconazole, Quinolone, Tetracycline, and Theophylline
   b. Digoxin, Phenytoin, Propranolol
   c. Phenobarbital, Salicylates: Causes Alkaline Urine
   d. Sulfonamides, L-Dopa, and Valproic Acid

Question 2

Acid Neutralizing Agents

1. Magnesium Hydroxide
   a. What do they cause?
2. Aluminum Hydroxide
   a. What do they cause?
3. How do we cancel out these issues?
4. 2 Uses of Antacids?

Answer 2

1. a. Increase Gastric Motility and CAUSE DIARRHEA
2. a. CONSTIPATION
3. Take the two together to cancel out their side effects!
4. Symptom relief of Heartburn and Gastritis; Adjunct to DRUG THERAPY in ULCER and GERD!!

Question 3

H2 Histamine Antagonists (CRFN -tidine)

1. What are the 4 we need to know?
2. These drugs: Do we need an Rx?

Answer 3

1. Cimetidine; Rantidine; Famotidine; Nizatidine

2. No. OTC drugs now.

Question 4

H2 Histamine Antagonists: Mechanism

1. What do they Inhibit?
2. Effective for TREATMENT of what 2 types of ulcers?
3. When are they given pre-operatively?

Answer 4

1. Gastric Acid Secretion by blocking H2 receptor on Parietal Cells
2. Gastric and Duodenal Ulcers
3. to decrease acidity of stomach contents, lessening damage if stomach contents are aspirated post-anesthesia.

(Uses: Ulcers, GERD, Pre-anesthesia, and w/H1 ANTAGONISTS for SEVERE ALLERGIC REACTION)

Question 5

H2 Histamine Antagonists

1. Pharmacokinetics
   a. Best given how?
   b. Half life?
   c. Duration of Action?
   d. Metabolized by what?
2. Side effects?
   a. Most common?

Answer 5

1. a. Oral
   b. 2-4 hrs
   c. Up to 12 hrs
   d. Liver and excreted by kidney
2. FEW (little to no effect on H1, but worse in elderly)
   a. Headaches, dizzy, nausea, rash, itching. Usually in old peeps w/impaired Renal function

Question 6

H2 Histamine Antagonists

1. Chronic CIMETIDINE does what?
   a. High doses can be used to treat what in females?
   b. What does CIMETIDINE INHIBIT?

Answer 6

1. Antiandrogen effect: Loss of Libido, Impotence and Gynecomastia can occur.
   a. to treat Masculinization in Females (Hirsutism)

b. INHIBITS CYP3A and decreases metabolism of many drugs. *Other H2 antagonists don’t inhibit CYP3A, so they don’t have drug interactions

Question 7

Proton Pump Inhibitors (POLER - Prazole)

1. What are the five drugs?

Answer 7

1. Pantoprazole; OMEPRAZOLE, Lansoprazole, Esomeprazole, Rabeprazole

Question 8

Proton Pump Inhibitors

1. What do they do?
   a. Useful in patients in which what drugs aren’t effective enough?
2. DOC for what?
3. Active or inactive form?
4. Side Effects?

Answer 8

1. IRREVERSIBLE blockage of Acid Formation
   a. Pts taking H2 receptor blockers that aren’t working well enough.
2. GERD
3. Given in Inactive Form. Become Active only in Parietal Cells that SECRETE GASTRIC ACID
4. MINIMAL

Question 9

Proton Pump Inhibitors

1. Activated drug binds IRREVERSIBLY to what in the Parietal Cell?
   a. How long can they last for?
2. MOST EFFECTIVE when?
3. MAY Decrease Absorption of what?

Answer 9

1. to H+,K+-ATPase
   a. Work up to 3 days
2. Take on an EMPTY STOMACH
3. of Ca2+ (Osteoporosis risk) with CHRONIC USE

Question 10

Effectiveness on Acid Production

1. How effective are Proton Pump Inhibitors?

Answer 10

1. Most effective on Duodenal Ulcers, GERD, and even H. Pylori than using an H2 Receptor Antagonist

Question 11

Prokinetic Agents

1. Neural regulation of Gastric Motility involves stimulation by what Neurons?
   a. Inhibition by what?
   b. Modulation by what 2 hormones?

Answer 11

1. Cholinergic Neurons
   a. by Adrenergic Neurons
   b. Dopamine and Serotonin

Question 12

Cytoprotective Agents

1. Misoprostol
   a. What does it do?
   b. Prevents ULCERATION INDUCED by what drug?
   c. What is it?
   d. CI?

Answer 12

1. a. Increases secretion of Mucus, decreases acid secretion
   b. by NSAIDs
   c. Prostaglandin E1 Analogue
   d. PREGNANCY! Can Induce Abortion!!

Question 13

Cytoprotective Agents

1. Bismuth Subsalicylate (Pepto Bismol) and Bismuth Citrate
   a. What does it do?
   b. Antibacterial Activity against what?
   c. Used with what 2 things?
   d. What 2 things can it cause?

e. Which is CI in peeps allergic to ASPIRIN?

Answer 13

1. a. Coats stomach and may directly inhibit the action of Pepsin
   b. H. Pylori
   c. Antibiotics and H2 Blockers for Peptic ulcer.

d. BLACK TONGUE and BLACK
STOOL

e. Pepto-Bismol (Subsalicylate)…use the Bismuth Citrate instead

Question 14

Prokinetic Agents

1. Bethanechol
   a. Type of Agonist?
   b. Treats what?
   c. Side Effects?
   d. DOESNT Get into what?

Answer 14

1. a. Muscarinic. Increases tone and motility in GI Tract
   b. Postoperative Ileus or to Increase lower Esophageal Sphincter Tone
   c. GI Cramping, etc.
   d. the CNS, so no Central Side Effects

Question 15

Prokinetic Agents

1. Metoclopramide
   a. Type of ANTAGONIST? Which does what?
   b. What is it exactly? Acts on what?
   c. COMMON Side Effects?
   d. Side Effects at HIGH DOSES?
   e. Don’t use in what?

Answer 15

1. a. D2 Antagonist; INCREASES ACh Release
   b. an ANTIEMETIC; on Chemoreceptor Trigger Zone in CNS
   c. GI Cramping, Diarrhea
   d. Extrapyramidal Symptoms
   e. in pregnancy

Question 16

Antispasmodics (Anticholinergic Agents)

1. Dicyclomine
   a. What is it?
   b. What 2 things does it decrease?
   c. Side Effects?
2. Tricyclic Antidepressants
   a. Used for what?

Answer 16

1. a. Antimuscarinic used as a GI Antispasmotic
   b. GI Activity and Spasms
   c. Anticholinergic (Dry mouth, sedation, etc)
2. a. IBS due to Anticholinergic Effect

Question 17

Anti-Nausea; Anti Emetic

1. Vomiting Center in Brain: Stimulated by many Inputs: Including what?
   a. What receptors are found here?
   b. Other inputs come from what areas?

Answer 17

1. Chemoreceptor Trigger Zone (CTZ)
   a. 5HT2 Receptors, D1, NK1 and Opioid Receptors
   b. Vestibular System (motion sickness, gag reflex in pharynx, and GI Mucosa (which has 5HT3))

Question 18

Anti-Nausea; Anti Emetic

1. Name 2 Antiemetics that Block DA, Muscarinic, and Histamine Receptors?
   a. Used in what situations?
   b. What is the MAJOR SIDE EFFECT?

Answer 18

1. Prochlorperazine and Promethazine
   a. Post-Op nausea and vomiting, Chemo, etc.
   b. HIGHLY SEDATING (blocking Histamine and Muscarinic Receptos)

Question 19

Anti-Nausea; Anti Emetic

1. What 4 Block 5HT3 Receptors (Antagonists)? (O-GDP -TRON)
   a. Best in Tx of Vomit due to what situations?
   b. Most COMMON Side Effects?
   c. NOT EFFECTIVE for Nausea and Vomiting due to what?

Answer 19

1. ODANSETRON, Granisetron, Dolasetron, and Palonosetron
   a. Chemo, Radiation, Post-op (Vagal Stimulation)
   b. Headache, Constipation, Dizziness
   c. Motion Sickness!
   * Used Prior to Chemo, Post-op and after Abdominal or Whole-body Radiation

Question 20

1. LAXATIVES SHOULD NOT BE USED if there is what 2 things?

2. How do they work?

Answer 20

1. INTESTINAL BLOCKAGE or PERFORATION!
2. Increase GI motility, Prevent Reabsorption of Water, Increase secretion of Water/Electrolytes, and Dissolve/Lubricate Feces

Question 21

Anti-Gas

1. Simethicone

Answer 21

1. GAS-X: gets rid of gas..probably use with LOTS of Fiber intake

Question 22

Antidiarrheals

1. Loperamide

Answer 22

1. DOES NOT ENTER CNS, Low abuse potential. Can cause abdominal pain, distention, constipation, dry mouth, nausea and vomiting.

Question 23

Antidiarrheals

1. Diphenoxylate plus Atropine

Answer 23

1. Opioid derivative w/Atropine: INHIBITS Cholinergic Receptors.

Atropine Reduces ABUSE Potential and INCREASES EFFECTIVENESS

NEED an Rx

DO NOT USE Opioids in Diarrhea due to Organisms. Allow organisms to invade the mucosa w/more time.

Question 24

Laxatives

1. What are the BULK-FORMING Laxatives?
   a. Effects are what? (mild, moderate, strong)
   b. Take with plenty of what?
   c. What 2 things are common?

d. High Fiber diet best prevents what 2 things?
e. What happens if you don’t take enough water?

Answer 24

1. FIBER, Methycellulose, Psyllium
   a. Mild
   b. Water
   c. Bloating and Flatulence

d. Constipation and Diverticulitis
e. Fecal impaction or Intestinal Obstruction can occur

Question 25

Laxatives: MUCOSAL AGENT 1. What does it stimulate? 2. Name of drug to know? 3. Moderate doses produce what? 4. Higher doses?

Answer 25

1. Peristalsis 2. SENNA 3. Semi-formed stool in 2-8 hrs 4. More intense effect * CASTOR OIL: DONT USE in Pregnancy. VERY INTENSE!!

Question 26

Laxatives: Osmotic (Think Water Bomb) 1. What do they do? 2. Magnesium Hydroxide

Answer 26

1. poorly absorbed salts or sugars that hold water in the intestine 2. This and Magnesium Sulfate

Question 27

Laxatives: Osmotic 1. Sodium Phosphate and Biphosphate

Answer 27

1. Oral or Enema. NEED LARGE AMTS OF WATER. DO NOT USE in peeps with CHF (due to SODIUM)

Question 28

Laxatives: Osmotic 1. Lactulose

Answer 28

1. Disaccharide. Decreases AMMONIA BUILDUP in pts w/Cirrhosis and other liver diseases

Question 29

Laxatives: Osmotic 1. Polyethylene Glycol

Answer 29

1. used with salts in some preparations for COLONOSCOPY or other intestinal Procedures. OTC in small amts (MIRALAX) for occasional Constipation

Question 30

Laxatives: LUBRICANT/SOFTENER 1. What do they do? a. MINERAL OIL: What can it cause if inhaled in the lungs? 2. Docusate Sodium

Answer 30

1. Increase bulk and soften and lubricate stool slightly...None are very effective a. Lipoid Pneumonia 2. Emulsifying agent. Lets water penetrate colon contents and soften them.

Question 31

Control of Gastric Acid Secretion 1. Predominant EXCITATORY CHOLINERGIC INPUT from what NERVE? 2. Parietal Cells secrete what? 3. ACh stimulated from nerve in (1) stimulates secretion of what? 4. Both Gastrin and ACH can induce release of what? 5. Histamine stimulates what receptors? a. What happens if these receptors are blocked?

Answer 31

1. From VAGUS NERVE 2. H+ in response to Gastrin, Muscarinic and Histaminergic stimulation 3. from Vegas Nerve; Stimulates ACID SECRETION 4. of Histamine 5. H2 receptors on Parietal cell to stimulate Acid secretion. a. Gastrin and Vagal Stimulation no longer have much effect on Acid Secretion

Question 32

What 3 types of Agens DECREASE ACID?

Answer 32

1. Neutralizing Agents 2. H2 Receptor Blockers 3. Proton Pump Inhibitors * Antimicrobial when H. Pylori is present

Question 33

Laxatives: Uses (5)

Answer 33

1. Decrease straining and make soft stools 2. Empty bowel for diagnostic procedures 3. DECREASED BOWEL TONE 4. GERIATRICS, preggos 5. Constipation

Question 34

Laxatives: CIs (5)

Answer 34

1. Nausea and Vomiting 2. Abdominal Cramps 3. Undiagnosed Abdominal Pain 4. Appendicitis 5. Intestinal Obstruction

Question 35

Diarrhea 1. Causes? 2. Drugs do 3 things?

Answer 35

1. IBS, Inflammation, Infection, Malabsorption, Thryotoxicosis, Meds 2. Absorb Water, Inhibit Secretion, Decrease Motility

Question 36

AntiDiarrheals: CI to Opioids 1. Infections 2. Ulcerative Colitis 3. Recovering Drug Addicets

Answer 36

1. Decrease expulsion of pathogens 2. toxic Megacolon 3. Abuse Potential