drugs REDUCING gastric acidity

Question 1

drugs which are neutralizing gastric acid:

Answer 1

ANTACIDS

Question 2

drugs which are inhibiting the gastric secretion:

Answer 2

1. H2 receptor antagonists
2. proton pump inhibitors (PPI)
3. antimuscarinic agents

Question 3

drugs included in ANTACIDS:

Answer 3

1. magnesium hydroxide
2. aluminium hydroxide
3. calcium carbonate
4. sodium bicarbonate

Question 4

mechanism of action → ANTACIDS:

Answer 4

1. neutralize stomach acid by reacting with protons in lumen of gut
2. may stimulate protective function of mucosa

Question 5

indications → ANTACIDS:

Answer 5

1. heart burn
2. indigestion
3. upset stomach
4. sour stomach

Question 6

side effects → ANTACIDS:

Answer 6

1. magnesium hydroxide → strong LAXATIVE effect

2. aluminium hydroxide → CONSTIPATING effect.

Question 7

drugs included in H2-receptor ANTAGONISTS:

Answer 7

1. cimetidine
2. ranitidine
3. famotidine
4. nizatidine

Question 8

mechanism of action of H2-receptor ANTAGONISTS:

Answer 8

1. block H2 receptors → decrease action of histamine in stomach secretion
2. reduce gastric acid secretion

Question 9

pharmacokinetics of H2-receptor ANTAGONISTS:

Answer 9

1. ORALLY
2. ulcer → 2x day or more
3. widely distributed
4. excreted in urine

Question 10

indications of H2-receptor ANTAGONISTS:

Answer 10

1. peptic ulcer, stress ulcer (PPIs are more effective)
2. reduce nocturnal acid secretion, accelerate healing, & prevent recurrences
3. GERD (PPIs are more effective)

Question 11

side effects of H2-receptor ANTAGONISTS:

Answer 11

1. generally well tolerated
2. cimetidine → endocrine effects = gynecomastia, galactorrhea
3. CNS symptoms (if given IV)
4. drug interactions

Question 12

drugs included in PPIs:

Answer 12

1. omeprazole
2. esomeprazole
3. lansoprazole
4. pantoprazole
5. rabeprazole

Question 13

pharmacokinetics of PPIs:

Answer 13

1. ORALLY
2. some are available as IV
3. converted to active drug in parietal cells → may need 3-4 days of treatment to achieve full effectiveness
4. enteric coated to prevent acid inactivation
5. metabolized in liver → t1/2 = 1-2h

Question 14

indications of PPIs:

Answer 14

1. GERD
2. peptic ulcer
3. non-ulcer dyspepsia
4. prevention of stress-related mucosal bleeding
5. Zollinger-Ellison syndrome
6. erosive esophagitis

Question 15

side effects of PPIs:

Answer 15

1. diarrhea, abdominal pain, nausea
2. headache
3. hypergastrinemia
4. increased risk of carcinoid & colon cancer
5. low vit. B12
6. drug interactions → with drugs that need acidic environment

Question 16

mechanism of action of PPIs:

Answer 16

irreversibly INACTIVATE parietal cell H+/K+ ATPase (resp. for production of acid)

2. blocking the transport of acid from the parietal cell to the gastric lumen