GI Pharma

Question 1

OTC antacids

(a) What are they?
(b) Absorbed?
(c) Onset?
(d) Possible side effect
(e) Example

Answer 1

OTC antacids 
(a) weak bases to neutralize stomach acid
(b) Not absorbed
(c) Rapid onset
(d) possible side effect = constipation
Ex: Tums, Rolaids

Question 2

TUMS

Answer 2

OTC antacid (weak base) to neutralize stomach acid

Question 3

Zantac

Answer 3

H2 receptor blocker- available OTC

Question 4

Pepsid

Answer 4

H2 receptor- available OTC

Question 5

PPIs- describe process of absorption and activation

Answer 5

PPIs ingested as a weak base. Taken up by activated parietal cells (activated by eating) and protonated.

Then protonated PPI can covalently bind and inactivate HK ATPase

Question 6

2 limitations of PPIs

Answer 6

• doesn’t inhibit nighttime acid secretion (parietal cell inactive) => nocturnal acid breathrough
• Short half life => long time (3-5 days) until peak onset

Question 7

Biggest worrisome risk of PPIs

Answer 7

-Infections: specifically C. dif and pneumonia

Question 8

3 ways prostaglandins are protective against acid

Answer 8

• decrease acid secretion
• increase bicarb and mucous secretion
• increase musocal bloodflow

Question 9

When do you take antacids?

Answer 9

30-60 minutes before meal (usually right before breakfast) b/c parietal cells get activated upon eating => most drug will be taken up and prootnated

Question 10

Sucralfate

Answer 10

-treat ulcers

Adheres to ulcers and acts as barrier of diffusion of H+ ions and pepsin

Question 11

Define nauseau

Answer 11

subjective, painless feeling that one may vomit

Question 12

Stimulation of what area causes nausea and vomiting?

Answer 12

-4th ventricle of the brain = area postrema

Question 13

What are some triggers of the area postrema?

Answer 13

• drugs: dopamine agonists
• toxins
• metabolic causes: uremia, hypercalcemia
• radiation exposure

Question 14

List some antiemetics

Answer 14

Antiemetics = anti-nausea

• Dopamine antagonists
• Serotonin receptor antagonists
• Tricyclic anti-depressants

Question 15

List drugs w/ some antiemetic properties

Answer 15

-antihistamines, anticholinergics

Question 16

Osmotically active laxatives

Answer 16

• increase the water content of stool => bowel distention and increased peristalsis
• very quick onset: 1-3 hrs

ex: Miralax, Go lightly, MIlk of Magnesia, Epsom Salt

Question 17

Miralax

Answer 17

Osmotically activate laxative

Question 18

Bulk Laxatives

Answer 18

= Fiber laxatives: insoluble and non-absorbable

• increase stool volume to trigger stretch receptors => reflex peristalsis to move contents forward
• must be taken w/ lots of water
• safest, often first line

Question 19

What do you need to be careful of when taking Metamucil?

Answer 19

Metamucil = bulk laxative

-make sure to take w/ lots of water

Question 20

Irritant Laxatives

Answer 20

• causes irritation of the enteric mucosa/nerves => water secretion => soften stool and increased volume => increased peristalsis
• not first line, don’t want to irritate stuff if you don’t have to

Question 21

Senakot

Answer 21

Irritant laxative

Question 22

Lubiprostone/Amitiza

Answer 22

activates Cl- channels = new mechanism of laxative

-used in IBS-C pts

Question 23

Lubricant laxatives

Answer 23

Retards water absorption to lubricate and soften stool

Question 24

Stool Softener

Answer 24

Not effective as a laxative

-decreases surface tension of stool

Question 25

Adsorbants

Answer 25

= Antidiarrheals - coats the gut wall - can bind to stuff (bugs, toxins, but also other drugs) to expedite their excretion - can cause tongue to turn black ex: pepto-bismol, kaopectate

Question 26

Pepti-bismol

Answer 26

= Adsorbant = Antidiarrheal

Question 27

Systemic anti-diarrheals

Answer 27

- opiate biased - slows GI mobility/peristalsis to allow for increased water absorption -also can use anticholinergics as systemic antidiarrheal

Question 28

What is the most universal symptom of IBS?

Answer 28

Abdominal pain 2nd most common = altered bowel habits

Question 29

Amitripyline

Answer 29

= TCA (tricyclic antidepressant) - inhibitory effect on the gut - used as antiemetic and to reduce sensitivity to pain in IBS

Question 30

Serotonin receptor blockers in IBS

Answer 30

- 5 HT3 and 5 HT4 antagonists previously used to treat IBS but taken off the market b/c of side effects - 5 HT3 antagonist => ischemic bowel (but a dif form used as antiemetic) - 5 HT4 antagonist => cardiac events

Question 31

What is Ogilvie's syndrome?

Answer 31

= pseudoobstruction = mimics acute large bowel obstruction -colon distends (most common in cecum) and risk of perforation is high => very high mortality if distends enough => if distends to a certain degree use Neostigmine (Ach-ase inhibitor) to cause decompression

Question 32

What can be used to treat pruritis in cholestatic disease?

Answer 32

- bile acid sequestrant | - CHolestyramine = Questran

Question 33

Medication for variceal bleeding

Answer 33

Somatostatin mimic = Octreotide = Sandostatin -inhibits release of many GI hormones (ex: gastrin, CCK etc) => decreases secretion from intestine and pancreas and decreases GI motility