Week 5 - Acid-Controlling Drugs

Question 1

what 3 types of receptors trigger stomach acid production

Answer 1

• gastrin
• ACh
• histamine

Question 2

what is the function of the proton pump

Answer 2

• pumps H+ from the parietal cell into the stomach lumen

- the H+ then combined with Cl to create stomach acid

Question 3

describe the carbonic anahydrase rxn

Answer 3

• CO2 is combined with H2O to create carbonic acid
• carbonic acid is broken down into H+ and HCO3- (bicarb) by carbonic anahydrase
• the H+ gets transported into the cell via the proton pump
• the bicarb gets shifted out of the cell

Question 4

what is the alkaline tide

Answer 4

• an efflux of bicarb into the blood after acid secretion in the stomach

Question 5

list the 3 types of acid-controlling drug

Answer 5

• antacids
• H2 antagonists
• proton pump inhibitors

Question 6

what is the primary function of antacids

Answer 6

• neutralize stomach acids

Question 7

what is the secondary function of antacids

Answer 7

• promote gastric mucosal defense mechanisms

Question 8

list 3 ways that antacids promote gastric mucosal defense mechanisms

Answer 8

thru the secretion of:

• mucus
• bicarb
• prostaglandins

Question 9

how does mucus provide protection

Answer 9

• protective barrier against HCl

Question 10

how does bicarb provide protection

Answer 10

• helps buffer acidic properties of HCl

Question 11

how do prostaglandins provide protection

Answer 11

• prevent activation of the proton pump & stimulates mucus production

Question 12

describe the onset of antacids

Answer 12

• typically very quick

Question 13

list 4 different types of antacids

Answer 13

• aluminum salts
• magnesium salts
• calcium salts
• sodium bicarb

Question 14

how are antacids used?

Answer 14

• used alone or in combo with each other

Question 15

what is the main side effect of aluminum salts

Answer 15

• constipation

Question 16

how is the side effect of aluminum salts avoided? how does this work?

Answer 16

• often used with magnesium to counteract constipation

- a side effect of magnesium is diarrhea = cancel each other out

Question 17

what type of patients are aluminum salts often recommended for? why?

Answer 17

• pts with renal disease

- bc they are more easily excreted

Question 18

what is an example of an aluminum salt

Answer 18

• aluminum hydroxide salt = amphojel

Question 19

what is a common side effect of magnesium salts? how is this avoided?

Answer 19

• diarrhea

- often combined w other drugs to counteract this effect

Question 20

what kind of patients should magnesium salts not be used in? why?

Answer 20

• in pts with renal failure

- bc the failing kidney cannot excrete extra magnesium = accumulation

Question 21

list 2 examples of magnesium salts

Answer 21

• magnesium hydroxide (milk of magnesia)

- magnesium carbonate = gaviscon ( can also be a combo)

Question 22

what are 2 examples of magnesium combo products

Answer 22

• Maalox & Mylanta (aluminum & magnesium)

Question 23

what is the most common form of calcium salts

Answer 23

• calcium carbonate

Question 24

what are 2 side effects of calcium salts

Answer 24

• constipation

- kidney stones

Question 25

how can calcium salts cause kidney stones

Answer 25

• bc too much calcium can lead to the development

Question 26

what kind of patients should calcium salts not be used in? why?

Answer 26

• not recommended for pts with renal disease

- bc may accumulate to toxic lvls

Question 27

describe the duration of calcium salts; what does this cause? how?

Answer 27

• long duration of acid action
• this can cause hyperacidity rebound
• bc the acid secretion is being blocked for so long, the stomach produces a ton of gastrin to try and compensate. so once the individual stops taking the med, all of that gastrin can suddenly trigger acid production

Question 28

what are calcium salts often advertised as

Answer 28

• an extra source of dietary calcium

Question 29

what is an example of calcium salts

Answer 29

• tums = calcium carbonate

Question 30

what is the MOA of histamine type 2 antagonsist (2)

Answer 30

• reduce acid secretion by blocking the action of histamine at the H2 receptors of acid-producing parietal cells
• reduce the production of H+ ions = reduced HCl

Question 31

how are H2 antagonists available?

Answer 31

• all available OTC in lower dosage forms

Question 32

how effective are H2 antagonists

Answer 32

• provide a 25-75% decrease in acid production

Question 33

list 1 example of H2 antagonists

Answer 33

• ranitidine (Zantac)

Question 34

what is the most popular drug for treatment of acid-related disorders

Answer 34

H2 antagonists

Question 35

what is a drug interaction associated eith H2 antagonists

Answer 35

• smoking decreases the effectiveness of H2 blockers

Question 36

what is the MOA of proton pump inhibitors

Answer 36

• irreversibly bind to H+/K+ ATPase enzyme (which are responsible for the proton pump)
• this bond prevents the movement of H+ ions from the parietal cell into the stomach

Question 37

how effective are proton pump inhibitors

Answer 37

block 100% of acid production for 24h

Question 38

what do proton pump inhibitors result in? what is this?

Answer 38

• achlorhydria

- ALL gastric acid secretion is temporily blocked

Question 39

what must happen for the cell to return to normal acid secretion after treatment w a proton pump inhibitor

Answer 39

• the parietal cell must synthesize new H+/K+ ATPase

- which takes ~1 day

Question 40

what is an example of a proton pump inhibitor

Answer 40

• omeprazole (prilosec or Losec)

Question 41

describe the short term adverse effect of proton pump inhibitors

Answer 41

• HA
• diarrhea
• NV

Question 42

describe the long term side effects of proton pump inhibitors (3)

Answer 42

• pneumonia
• fractures (low) due to low calcium absorption
• rebound hypersecretion

Question 43

what is a fear associated with proton pump inhibitors

Answer 43

• fear of increased risk of infection (lack of acid could cause bacteria overgrowth)

Question 44

list 2 miscellaneous peptic ulcer drugs

Answer 44

• sucralfate (carafate)

- misoprostol (cytotec)

Question 45

what is sucralfate

Answer 45

• coating agent & cytoprotective drug

Question 46

what is sucralfate used for

Answer 46

• stress ulcers

- peptic ulcer disease

Question 47

what is the MOA of sucralfate

Answer 47

• attracted to & binds to the base of ulcers & erosions, forming a protective barrier over these areas
• protects these areas from pepsin = prevents the ulcers from worsening

Question 48

what is misoprostol

Answer 48

• synthetic prostaglandin analog

= can artifically restore prostaglandin cytoprotective activity

Question 49

describe the cytoprotective activity of prostaglandin (4)

Answer 49

• protect gastric mucosa from injury by enhancing local production of mucus
• inhibits acid production at higher doses
• promotes local cell regeneration
• helps maintain mucosal blood flow

Question 50

what is misoprostol specifically used for

Answer 50

• prevention of NSAID induced gastric ulcers

Question 51

describe side effects of misoprostol

Answer 51

doses that are therapeutic enough to treat duodenal ulcers often produce:

• abdominal cramps
• diarrhea

Question 52

describe the side effects of H2 receptor antagonists

Answer 52

• very few

- may increase risk of aspiration

Question 53

what is one thing to consider with antacids

Answer 53

• give one hour apart from H2 antagonists and sulcrafate

Question 54

describe the general safety of proton pump inhibitors

Answer 54

• generally v safe & tolerated well with few side effects