Upper GI pharm [3]

Question 1

PPI

• Class
• MOA

Answer 1

Antisecretory/cytoprotective agent

inhibits H-K-ATPase in parietal (oxyntic) cell

Question 2

Uses of PPI (what diseases)

Answer 2

GERD (most effective)
Peptic ulcer disease (faster relief than H2 antag)
NSAID induced (preferred)
Stress gastritis (preventive)
ZE syndrome

Question 3

H2 antagonist

• class
• MOA

Answer 3

Antisecretory/cytoprotective agent
competitive reversible block of H2 receptors on BASOLATERAL membrane

• less effective than PPIs + more rapid onset of action than PPI in acute gastritis

Question 4

Uses of H2 antagonist

[Ranitidine, cimetidine]

Answer 4

GERD
PUD (but mainly PPI)
Stress related gastritis

Question 5

Misoprostal

Answer 5

PG agonist that acts on epithelial cell to decrease H+ secretion and increase mucus bicarb

• uses: NSAID induced ulcers

Question 6

Side effects of PPI

[omeprazole, lansoprazole]

Answer 6

mild: headache, abdominal pain, nausea, constipation, diarrhea
HYPER-gastrinemia (w/ chronic PPI use)
- like pseudo ZE!

Question 7

DDI of PPI

[omeprazole, lansoprazole]

Answer 7

act on CYP450

- omeprazole can inhibit conversion of antiplatelet agent clopidogrel to active form

Question 8

H2 receptor antagonist side effects

[omeprazole, lansoprazole]

Answer 8

gynecomastia

dosage reduction in renal dysfxn

Question 9

DDI of H2 receptor antagonist

[omeprazole, lansoprazole]

Answer 9

Cimetidine inhibits CYP450 oxidative metabolism → increase toxicity of some drugs (warfarin, phenytoin, carbamazepine, BDZ)

Question 10

All antisecretory agents decrease _______ absorption → ______

Answer 10

ketoconazole

increase gastric pH

Question 11

actions of proton pump inhibitors and prostaglandins in protecting the gastrointestinal tissues

Answer 11

PPI: prodrug → get into circulation → activated in parietal cells
- only inactivates active pumps

Prostaglandin analog
inhibit cAMP in parietal cells → decrease H+ and stimulate neutralizing HCO3- formation and cytoprotective mucus formation
- CONTRAINDICATED IN PREGGOS

Question 12

Ideal antacid should:
rapidly raise pH of stomach contents to _____
Absorbable or nonabsorbable?
short or long acting?

Answer 12

4-5 (but if 7 can lead to rebound acid secretion)
be nonabsorbable
long acting

and have NO undesirable side effects
- can use Mg [diarrhea] with Al or Ca [constipation] to counteract each others effects

Question 13

Primary ingredients in antacids

Answer 13

Calcium → constipation + hypercalcemia
Aluminum → constipation + CNS toxicity
Magnesium → osmotic diarrhea + exacerbate renal dis
NaHCO3 → potent but contraindicated for systemic effects + pregnancy

Question 14

Prokinetic agents
[metoclopramide]
- MOA
- tx for?

Answer 14

directly or indirectly increase agonist activity at smooth muscle M3 receptors

• bowel motility (achalasia, gastoparesis)
• Esophagitis associated with GERD

(note that metoclopramide is an antagonist at D2 to inhibit the release of ACh, which leaves less to act on M3)
- increase coordinated contraction → enhance transit

Question 15

Antiemetic agent: 5HT3 receptor antagonist
[ondansetron]
- MOA

Answer 15

block 5HT3 receptors at chemoreceptor trigger zone (CTZ)

• prevention in use of cytotoxic drugs, opioid analgesics

Question 16

Antiemetic agent: 5HT3 receptor antagonist
[ondansetron]
- side effects

Answer 16

constipation
increase dose → increase QT

• safe in pregnancy vomiting/nausea!!!!! yay

Question 17

Antiemetic agent: D2 receptor antagonist
[metoclopramide]
- MOA

Answer 17

block DA receptors at CTZ

• use for nausea/vomiting of chemotherapy
• effective in n/v for pregnancy!!! (just like 5HT3 R antag)

Question 18

Antiemetic agent: D2 receptor antagonist
[metoclopramide]
- side effects

Answer 18

Extrapyramidal side effects