Week 6: Acid-Reducing and Cyto-protective agents

Question 1

Antacids indications

Answer 1

hyperacidity (heartburn), PUD (sx control), GERD

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
• calcium carbonate NEED Vitamin D to be absorbed

Question 4

Antacid cautions/ contraindications

Answer 4

• avoid Al and Mg-based antacids in renal impairment (renally excreted) - think metalic
• avoid Ca based antacids in hypercalcemia

- SEPARATE from other medications by at least 2 hours to avoid interactions.

- if taken on empty stomach, reduce acid for only 20-40 mins but if taken with meals, lasts longer.

- increase absorption of enteric coated meds and decrease bioav of some meds

• don’t use in abd pain of unknown origin
• caution in Na restriction pt’s (HF pts)

Question 5

Antacid ADRs

Answer 5

Aluminum and Calcium: constipation

Magnesium-based: diarrhea (think Milk of Magnesia)

Question 6

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

Answer 6

Cytoprotective agents

Question 7

Sucralfate (Carafate) indications for use

Answer 7

prophylaxis and treatment of duodenal ulcers a/s with NSAID use and from other causes

Question 8

Sucralfate (Carafate) pharmacodynamics

Answer 8

• True cytoprotective
• selectively bind to necrotic ulcer tissue, covering it and acting as a barrier to outside stimuli such as acids
• not absorbed systematically

Question 9

Sucralfate (Carafate) Cautions/ contraindications and AED

Answer 9

• EMPTY stomach before 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

• caution < 30 CrCl in geriatrics

Question 10

Misoprostol (Cytotec) MOA

Answer 10

• inhibits gastric secretion via inhibition of hitsamine stimulated cAMP; increases mucus & bicarbonate for protective qualities
• synthetic prostaglandin (vasodilation, uterine contraction, decreased gastric acid secretion, and increases mucosal thickness)

Question 11

Misoprostol (Cytotec) cautions/contraindications

Answer 11

- Preg Category X (birth defects)

• caution in renal impairment

Question 12

GERD meds

Question 13

Misoprostol (cytotec) ADRs

Answer 13

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

Question 14

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 14

1) acetylcholine 2) gastrin 3) histamine

Question 15

To what drug class do Ranitidine and Famotidine belong?

Answer 15

Histamine 2 Receptor Antagonists (H2RAs) “-tidine”

Question 16

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

Answer 16

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

Question 17

Potency in controlling gastric acid secretion

Answer 17

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

Question 18

Which H2RA drug has the most potential for ADRs?

Answer 18

Cimetidine (Tagamet)

• has greater androgen and CNS effects (confusion, agitation)
• gynecomastia and impotence

Question 19

H2RA cautions/ contraindications

Answer 19

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

Question 20

H2RA (Pepcid, Zantac, Tagamet) ADRs

Answer 20

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

Question 21

Proton Pump Inhibitors examples and indications for use

Answer 21

• 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 22

Proton pump inhibitors MOA

Answer 22

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%
• decreases production of stomach acid for up to 72 hours

Question 23

PPI cautions/contraindications

Answer 23

• metabolized in the liver - use cautiously in pts with hepatic dz and in elderly
• Black box warning: Omeprazole and clopidogrel/Plavix drug interaction = reduce effectiveness of Plavix when taken with Omeprazole
• Drug absorption of acid drugs is reduced (ex. calcium needs an acidic environment to be absorbed)

Question 24

PPIs ADRs

Answer 24

• nausea, diarrhea, headache, abdominal pain,

Long term use (not recommended) can lead to:

“PPI” osteoporosis and bone fx., C-diff infections, pneumonia”, hypOmagnesemia, and Vitamin B12 deficiency

• calcium needs an acidic environment to be absorbed

Question 25

PPIs indication

Answer 25

• 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 26

H. Pylori triple therapy regimen

Answer 26

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 27

PUD Treatment - dosing

Answer 27