Drugs Affecting Gastrointestinal Tract (GIT) Acid

Question 1

what is GERD?

Answer 1

Passage of gastric contents into the esophagus becomes a disease when it causes macroscopic damage or symptoms that reduce QOL

Question 2

what is Erosive esophagitis?

Answer 2

visible breaks with/without symptoms

• Lining erodes away and can have visible breaks
• Diagnosed via endoscopy (EGD)

Question 3

what is Nonerosive reflux disease (NERD)?

Answer 3

symptoms of GERD without visible mucosal injury

Question 4

When acid gets exposed to esophagus the tissue types can change (hyperplasia) and lead to ____ in esophagus.

Answer 4

cancers

Question 5

Recommend endoscopy if patient has what?

Answer 5

1. Heartburn with alarm symptoms (dysphagia, odynophagia, GI bleeding, anemia, weight loss, recurrent vomiting)
2. Severe erosion on initial scope–>Repeat after 2 months of PPI
3. Men >50 yo with chronic (>5 years) GERD and additional risk for Barrett’s esophagus and esophageal adenocarcinoma (nocturnal reflux, hiatal hernia, elevated BMI, tobacco use, intraabdominal fat)
4. GERD symptoms that persist despite therapeutic trial of 4-8 weeks of BID PPI

Question 6

what are the classes of drugs to treat GERD in order of lowest potency to highest potency?

Answer 6

1. OTC antacids and histamine2-receptor antagonists (H2RA) at OTC doses
2. H2RA at Rx doses
3. Proton Pump Inhibitors (PPI)

Question 7

The classes of drugs affecting the physiology of the production of acid are the ______

Answer 7

PPIs and the H2RAs

Question 8

Antacids MOA

Answer 8

neutralize gastric acid so have a relatively fast onset

Question 9

Antacid products

Answer 9

o Alka-Seltzer - NaHCO3 and/or KHCO3

o Maalox (liquid) - Al(OH)3 and Mg(OH)2

o Maalox (tablet) - CaCO3

o Milk of Magnesia - Mg(OH)2
o Pepto-Bismol - C7H5BiO4

o Pepto-Bismol Children’s - CaCO3

o Rolaids - CaCO3 and Mg(OH)2

o Tums - CaCO3

o Mylanta - Al(OH)3

Question 10

Antacids are often used for what kind of GERD symptoms?

Answer 10

Often used for mild symptoms and for heartburn (i.e., symptoms less than once per week)

Question 11

do antacids prevent GERD?

Answer 11

no

Question 12

MC antacids that are used?

Answer 12

Rolaids and tums

Question 13

what are the 4 Histamine2-receptor Antagonists (H2RAs)

Answer 13

1. Cimetidine (Tagamet)
2. Famotidine (Pepcid, et al.)
3. Nizatidine (Axid)
4. Ranitidine (Zantac)

Question 14

Histamine2-receptor Antagonists MOA

Answer 14

inhibit histamine at H2-receptors of gastric parietal cells (and other tissues but not very clinically useful)

Question 15

Histamine2-receptor Antagonists can sometime treat what other disease besides GERD?

Answer 15

chronic urticaria

Question 16

what 2 Histamine2-receptor Antagonists can be used IV?

Answer 16

Ranitidine (Zantac)

Famotidine (Pepcid, et al.)

Question 17

what 2 Histamine2-receptor Antagonists are most used?

Answer 17

Ranitidine (Zantac)

Famotidine (Pepcid, et al.)

Question 18

what Histamine2-receptor Antagonists comes in a PO tablet only

Answer 18

Cimetidine (Tagamet)

Question 19

which Histamine2-receptor Antagonist Inhibits CYP450 metabolism and has several important DDIs

Answer 19

Cimetidine (Tagamet)

Question 20

what are some drugs that Cimetidine (Tagamet) has DDIs with because of the CYP450 metabolism

Answer 20

warfarin, phenytoin, diazepam, carbamazepine

Question 21

what is special about Ranitidine (Zantac)

Answer 21

Longer acting and more potent than cimetidine

No enzyme inhibition

Question 22

what is special about Famotidine

Answer 22

More potent than ranitidine

Question 23

what is special about Nizatidine (Axid)

Answer 23

No liver metabolism so would be good in patients with liver disease

Question 24

if your pt has liver disease and needs a Histamine2-receptor Antagonist, which one would you prescribe?

Answer 24

Nizatidine (Axid)

Question 25

Histamine2-receptor Antagonist reduce the absorption of__

Answer 25

FQs

Question 26

Histamine2-receptor Antagonist ADRs

Answer 26

- Most are well-tolerated with some GI upset and HA - Cimetidine has more and different ADRs :antiandrogenic actions so men can get gynecomastia, and galactorrhea, Women can get breast tenderness and changes in menstruation from this

Question 27

DDIs of Histamine2-receptor Antagonist

Answer 27

Some drugs require acid (e.g., iron, digoxin, ampicillin) to be absorbed so coadministration can reduce effectiveness

Question 28

Most potent and MC used class of drugs for GERD

Answer 28

Proton Pump Inhibitors (PPIs)

Question 29

Proton Pump Inhibitors (PPIs) MOA

Answer 29

bind to active H+/K+-ATPase enzyme units (proton pump) of gastric parietal cells to suppress the secretion of H+ into the gastric lumen

Question 30

Proton Pump Inhibitors (PPIs) drugs end in what?

Answer 30

PRAZOLES

Question 31

what are the PPI drugs?

Answer 31

``` Rx and OTC o Omeprazole (Prilosec) o Pantoprazole (Protonix) - IV and PO o Lansoprazole (Prevacid) - IV and PO ``` ``` Rx ONLY o Rabeprazole (AcipHex) o Esomeprazole (Nexium) - IV and PO o Dexlansoprazole (Dexilant) ```

Question 32

PPIs are prodrugs that need what kind of environment to be activated?

Answer 32

acidic

Question 33

When should PPIs be taken?

Answer 33

in morning, 30-60 min before meal. if BID then second dose before a meal.

Question 34

Do PPIs work instantly?

Answer 34

no, it may take several days to achieve maximal efficacy

Question 35

What is an important DDI with omeprazaole?

Answer 35

clopidogrel ****Omeprazole (Prilosec) and clopidogrel (Plavix- antiplatelet): decreased action of clopidogrel due to 2C19 inhibition. You need 2C19 to activate clopidogrel, so if you don't have that you lower effectiveness of clopidogrel and this increases the chance for them to clot.

Question 36

A DDI for PPIs and Protease Inhibitors (used to treat HIV)?

Answer 36

reduced absorption of some Protease Inhibitors