Agents for GERD

Question 1

What are the drug therapy goals in treating GERD?

Answer 1

1. Eliminate Symptoms 2. Heal Esophagitis 3. Prevent the relapse of esophagitis 4. Prevent the development of complications

Question 2

What types of medications are useful in the treatment of GERD?

Answer 2

Antacids H2- Receptor Blockers PPIs Prokinetic Agents (Cisapride, Metoclopramide, Bethanechol) Mucosal Protectants (Sucralfate)

Question 3

MOA of Antacids

What electrolyte imbalance do ALL antacids cause?

Answer 3

Weak bases that increase gastric pH through acid-neutralizing ability to form a salt & water

• Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric & urinary pH or by delaying gastric emptying

*****ALL antacids cause HYPOKALEMIA****

Question 4

H2-Blockers MOA

Answer 4

Competitively block H2 receptors on gastric parietal cells, thereby decreasing acid production (Reverible)

Question 5

PPIs MOA

Answer 5

Irreversibly inhibit gastric parietal cell H/K-ATPase inhibiting gastric acid secretion

Question 6

Cisapride MOA

Answer 6

increases LES pressure accelerates gastric emptying time increases amplitude of esophageal contractions 5-HT4 agonist 5-HT3 antagonist

Question 7

Metoclopramide

Answer 7

D2 receptor blocker increases LES pressure accelerates gastric emptying time

Question 8

Sucralfate

Answer 8

complexes with positively charges proteins to form a viscous coat when exposed to acid- thereby protecting gastric lining from gastric acid secretions

Question 9

What are adverse s/e caused by metoclopramide?

Answer 9

Anxiety Insomnia Extrapyramidal Symptoms Increased Prolactin levels

Question 10

What are the adverse effects cause by sucralfate?

Answer 10

Constipation Nausea Abdominal Discomfort

Question 11

Which antacids can produce a metabolic alkalosis?

Answer 11

Sodium Bicarbonate Calcium Carbonate

Question 12

What are the possible adverse effects of Aluminum Hydroxide antacids?

Answer 12

• aluMINIMUM amount of feces=Constipation
• Hypophosphatemia
• Proximal muscle weakness
• Osteodystrophy- bone damage via binding phosphate in the gut
• Seizures

Question 13

What are the possible adverse effects of Magnesium Hydroxide antacids?

Answer 13

• Mg= Must Go to the bathroom! Diarrhea
• Hyporeflexia
• Hypotension
• Cardiac Arrest

Question 14

What are the possible adverse effects off Calcium Carbonate antacids?

Answer 14

• Hypercalcemia
• Rebound increase in acid when use is halted
• Can chelate & decrease the effectivenesss of other drugs (eg tetracycline)
• belching
• Constipation

Question 15

What causes the milk-alkali syndrome?

Answer 15

Ingestion of excessive amounts of calcium & absorbable alkali such as sodium bicarbonate or calcium carbonate

Question 16

What is a potential complication after d/c chronic antacid use?

Answer 16

Acid rebound

Question 17

List the H2-Blockers

Answer 17

“-TIDINE” CimeTIDINE FamoTIDINE RaniTIDINE NizaTIDINE

Question 18

Which H2-Blocker inhibits hepatic cyt P-450 metabolizing enzymes?

Answer 18

Cimetidine

Question 19

Which H2-Blocker can cause gynecomastia?

Answer 19

Cimetidine (prolactin-stimulating activity)

Question 20

Which H2-Blocker has antiandrogenic activity?

Answer 20

Cimetidine

Question 21

What are the common s/e of PPIs?

Answer 21

• Prolonged use–> bacterial overgrowth in the GI tract= increased risk for C.Diff infxn
• Pneumonia
• decreased serum Mg w long-term use
• pts>50 yo taking chronic high doses of PPIs have increased risk of hip fractures

Question 22

What is the most serious s/e of Cisapride?

Answer 22

Prolongation of QT interval

Question 23

What arrhythmia can be caused by prolongation of the QT interval?

Answer 23

Torsades de points (polymorphic ventricular tachycardia)

Question 50

Cisapride should be avoided in which type of pts?

Answer 50

• Pts with prolonged QT intervals
• Pts taking medications that inhibit cyt P-ESO 34A
  
  • Fluconazole
  • Ketoconazole
  • Itraconazole
  • Erythromycin
  • Clarithromycin
  • Ritonavir

Question 51

Which drugs increase Cisapride blood levels by inhibiting the cyt P-450 34A enzymes that metabolize Cisapride?

Question 52

What is the class of drugs that ends in “-dine”?

Answer 52

H₂ Blockers

• Cimetidine
• Ranitidine
• Famotidine
• Nizatidine

Take H₂ Blockers before you DINE- think “table for 2” to remember H₂

Question 53

What are the clinical uses for H2 Blockers?

Answer 53

• Peptic Ulcer
• Gastritis
• Mild Esphagel Reflux

Question 54

What are the toxicities associated with Cimetidine?

Do other H2 blockers share these same effects?

Answer 54

• Potent inhibit of cyt P-450 (multiple drug interactions)
• Antiandrogenic effects
  
  • PL release
  • Gynecomastia
  • Impotence
  • Decreased Libido in males
• Can cross BBB & Placenta
  
  • Confusion
  • Headaches
  • Dizziness
• Decreases renal excretion of Creatinine (ALSO RANITIDINE)

Other H2 blockers are relatively free of these effects

Question 55

What are the clinical uses for PPIs?

Answer 55

• Peptic Ulcer
• Gastritis
• GERD
• Zollinger-Ellison Syndrome