Week 6: Acid-Reducing and Cyto-protective agents

Question 1

Antacids indications

Answer 1

Used for mild intermittent acid reflux/heartburn, GERD - symptom control

• may be used as adjunct therapy for PUD - does not treat the PUD, just for symptom control

Question 2

Antacid formulations

Answer 2

• aluminum hydroxide
• magnesium hydroxide
• calcium carbonate

Question 3

Antacid MOA/pharmacodynamics

Answer 3

• neutralizes stomach acid making it more basic
• antacids are weak bases that interact with hydrochloric acid in the stomach to reduce gastric acidity and increase pH

Question 4

Antacid pharmacokinetics

Answer 4

• Aluminum and magnesium hydroxide are not absorbed with normal use
• calcium carbonate is absorbed if taken with Vitamin D

Question 5

Antacid cautions/ contraindications

Answer 5

• avoid aluminum and magnesium-based antacids in renal impairment (renally excreted) - think metalic

- antacids should be separated from other medications by at least 2 hours to avoid interactions - take 1 to 3 hours after meals

• contact provider if using for longer than 2 weeks

Question 6

Antacid ADRs

Answer 6

Aluminum and Calcium-based antacids can cause constipation

Magnesium-based antacids can cause diarrhea (think Milk of Magnesia)

Question 7

Sucralfate (carafate) and Misoprostol (Cytotec) are examples of what type of medication?

Answer 7

Cytoprotective agents

Question 8

Sucralfate (Carafate) indications for use

Answer 8

prophylaxis and treatment of moderate to severe peptic ulcer disease

Question 9

Sucralfate (Carafate) pharmacodynamics

Answer 9

• True cytoprotective - selectively bind to necrotic ulcer tissue, covering it and acting as a barrier to outside stimuli such as acids

Question 10

Sucralfate (Carafate) Cautions/ contraindications

Answer 10

• should be taken on an empty stomach prior to meals
• instruct patient to separate the use of this medication and others - take other mediations at least 2 hours before or 6 hours after taking this medication - affects absorption of other drugs

Contains aluminum - can cause constipation

Question 11

Misoprostol (Cytotec) MOA

Answer 11

• G-protein inhibitor - turns off the secondary messenger which turns off the gastric proton pump
• synthetic prostaglandin (vasodilation, uterine contraction, decreased gastric acid secretion, and increases mucosal thickness)

Question 12

Misoprostol (Cytotec) cautions and contraindications

Answer 12

• Avoid in pregnancy and lactation - pregnancy category X -
• should be taken with food
• use with caution in renal impairment

Question 13

GERD meds

Question 14

Misoprostol (cytotec) ADRs

Answer 14

• diarrhea, abdominal pain, nausea, postmenopausal bleeding, headache

Question 15

What are the 3 types of receptors on the parietal cell that can be stimulated to cause the production of acid or blocked to reduce the production of acid?

Answer 15

1) acetylcholine 2) gastrin 3) histamine

Question 16

To what drug class do Ranitidine and Famotidine belong?

Answer 16

Histamine 2 Receptor Antagonists (H2RAs) “-tidine”

Question 17

Histamine 2 Receptor Antagonists (Zantac, Pepcid, Tagamet) MOA

Answer 17

• Reversibly competitive inhibition of histamine at H2 receptors of the gastric parietal cells, thus inhibiting gastric acid secretion - reduces stomach acid by 35 to 50%
• prevents the progression of GERD

Question 18

Potency in controlling gastric acid secretion

Answer 18

• Ranitidine is 5 to 12 times more potent than cimetidine
• Famotidine is 30 to 60 times more potent than cimetidine

Question 19

Which H2RA drug has the most potential for ADRs?

Answer 19

Cimetidine (Tagamet) - has greater androgen effects

• CNS effects (confusion, agitation)
• gynecomastia and impotence
• multiple drug interactions because is uses several isoenzymes - Alot of CYP 450 involvement

Question 20

H2RA cautions/ contraindications

Answer 20

• caution in renal impairment
• safe in pregnancy (except Cimetidine)
• approved in pediatrics (except Cimetidine)

Question 21

H2RA (Pepcid, Zantac, Tagamet) ADRs

Answer 21

headache, dizziness, confusion, agitation, psychosis, depression, blood dyscrasias (agranulocytosis, granulocytopenia, thrombocytopenia, and aplastic anemia)

Question 22

Proton Pump Inhibitors examples and indications for use

Answer 22

• Omeprazole, Pantoprazole, Esomeprazole (-prazole’s)
• used for duodenal and gastric ulcers, erosive gastritis, Zollinger-Ellison syndrome, GERD
• peptic ulcer disease as part of the treatment for H-pylori

Question 23

Proton pump inhibitors MOA

Answer 23

Inhibit gastric proton pumps specifically, the H+/K+-ATPase pump located on the parietal cells to suppress acid secretion

• reduces acid secretion by more than 90%
• inhibitor that turns off the proton pump that moves hydrogen ions into the stomach where they combine with chloride in the stomach which forms HCl acid
• decreases production of stomach acid for up to 72 hours

Question 24

PPI cautions/contraindications

Answer 24

• metabolized in the liver - use cautiously in pts with hepatic dz and in elderly
• Omeprazole and Plavix drug interaction - CYP2C19 - decreased effectiveness of Plavix when taken with Omeprazole
• Drug absorption of acid drugs is reduced (ex. calcium needs an acidic environment to be absorbed)
• Esomeprazole, omeprazole, and lansoprazole safe in pregnancy and pediatrics
• Pantoprazole and Rabeprazole not safe in pregnancy;

Question 25

PPIs ADRs

Answer 25

• nausea, diarrhea, headache, abdominal pain,

Long term use (not recommended) can lead to osteoporosis and bone fx., C-diff infections, hypomagnesemia, and Vitamin B12 deficiency - calcium needs an acidic environment to be absorbed

Question 26

PPIs clinical use

Answer 26

• combined with antibiotics to treat H. pylori
• Used for 8 weeks to treat GERD then weaned off - may double dose for 4 weeks than decrease dose for 4 weeks then wean off
• smoking stimulates the nicotinic acytylcholine receptors in the gastric cells - increases gastic acid secretion - counseling patient to stop smoking can significantly decrease GERD symtoms

Question 27

H. Pylori triple therapy regimen

Answer 27

1) PPI once or twice daily
2) Amoxicillin 1gm BID
3) Clarithromycin 50mg BID

Take above for 7 to 10 days (up to 14 days)

OR (w/ PCN allergy)

replace #2: Metronidazole 500mg BID

Take triple therapy with above for 10 to 14 days

Question 28

PUD Treatment - dosing

Answer 28