Pharm - GI Potpourri Flashcards
1
Q
What are the salts commonly used in antacids?
A
- Mg++ salts
- Al++ salts
- Ca++ carbonate
2
Q
ADRs Mg salts
A
- diarrhea
- avoid in renal dysfunction
3
Q
ADRs of Al salts and Ca carbonate
A
- constipation
- avoid in renal dysfunction
4
Q
What is the place in therapy in the tx of GERD for antacids?
A
- used for pts w/ mild/intermittent sx
- can be taken on an “as needed” basis
5
Q
MoA of antacids
A
- weak bases that neutralize gastric acid to form salt and water
- also enhance GI mucosal defenses by stimulating prostaglandin production or binding substances that may be toxic
6
Q
onset and duration of antacids
A
- rapid onset
- short duration: 30min - 3 hrs
7
Q
counseling points for antacids
A
- separate by 2 hrs from tetracyclines and fluoroquinolones
- take 1 hr following a meal for most relief
8
Q
What are the H2 receptor antagonist (H2RAs) products?
A
- famotidine (pepcid)
- ranitidine (zantac) - preferred in pregnancy
- nizatidine (axid)
- cimetidine (tagamet)
9
Q
What is H2RA dosing based on?
A
a low dose (OTC) and standard dose (Rx)
10
Q
common ADR of H2RAs
A
tachyphylaxis (body learns how to work around it)
11
Q
place in therapy for H2RAs in the tx of GERD
A
- effective for mild to moderate GERD
- can be used on an “as needed” basis
12
Q
MoA of H2RAs
A
- reversible**, competitive antagonist of histamine at the H2 receptor on the membrane of acid-secreting parietal cells
- selective for H2, does not effect H1
13
Q
onset and duration of H2RAs
A
- slower onset compared to antacids
- reaches peak at 2.5 hrs but duration is 4-10 hrs
14
Q
counseling points for H2RAs
A
- faster osnet than PPIs, but tolerance develops
- use has declined since intro of PPIs
- pregnancy category B
15
Q
What is the drug of choice for the tx of moderate to severe GERD and PUD?
A
-PPIs: omeprazole
16
Q
ADRs of PPIs
-these are important to know
A
- infections: c. diff, pneumonia
- malabsorption
- kidney dz
- drug induced lupus
- mortality
17
Q
what malabsorption risks occur in using a PPI?
A
- mild reduction in iron
- mild reduction in B12
- significant impairment of magnesium absorption - hypomagnesemia
- significant impairment of Ca absorption
18
Q
what is the place in therapy for PPIs in the tx of GERD?
A
drug of choice in moderate-severe GERD
19
Q
MoA of PPIs
A
- irreversibly inhibits H+/K+ ATPase (proton pump) in the gastric parietal cell
- prodrugs
- irreversible and covalently bound so very powerful
20
Q
onset and duration of PPIs
A
-more potent and longer lasting than H2RAs
21
Q
counseling points for PPIs
A
- take 30 min before meals
- usually taken in the morning but can be taken at night if nighttime sx
- administer daily, not “as needed”
22
Q
drug interactions of PPIs
A
-omeprazole and clopidigrel** b/c omeprazole inhibits CYP2C19
23
Q
what are the PPI products available?
A
- omeprazole (prilosec) (one we have to know)
- lansoprazole (prevacid)
- dexlansoprzole (dexilant)
- esomeprazole (nexium)
- pantoprazole (protonix)
- rabeprazole (aciphex)
- omeprazole/sodium bicarb (Zegerid)
24
Q
Al hydroxide / sucrose sulfate product
A
-sucralfate (carafate)
25
sucralfate place in therapy for the tx of GERD
-most commonly used in the tx of and prevention of PUD
26
MoA of sucralfate
- forms viscous gel in the presence of acid
- adheres to epithelial cells and ulcers creating a barrier
- enhances GI mucosal protective factors
27
lifestyle modifications for the tx of GERD
- elevate head of bed (esp if night sx)
- weight reduction in obese pts
- avoid: fats, chocolate, alcohol, peppermint/spearmint
- avoid: spicy foods, OJ, tomato juice, coffee
- eat small meals
- avoid eating immediately prior to sleeping
- stop smoking
- avoid tight fitting clothes
28
drugs to avoid in GERD
- drugs that have a direct irritant effect on esophageal mucosa
- bisphosphonates
- tetracylcines
- K+Cl
- iron salts
- aspirin
- NSAIDs
- if can't be avoided: take w/ plenty of liquid
29
Tx of mild/intermittent GERD? And what is the appropriate step up therapy?
1. lifestyle modifications
2. PRN low dose H2RAs and/or antacids
3. increase to standard dose of H2RAs for 2 wks
4. if still not working, dc H2RA and start PPI (8 weeks max)
30
tx of severe/frequent sx of GERD or erosive esophagitis
-start w/ standard dose PPI daily for 8 weeks plus lifestyle change
31
management of recurrent sx and maintenance therapy of GERD
- many pts relapse when acid acid suppression is dc
- all GERD pts should have a trial off meds unless they have erosive esophagitis, they should remain on PPI
- pts w/ recurrent sx should be managed w/ same tx
32
given a pt w/ h. pylori, what is the first line combo tx for PUD?
- bismuth quadruple therapy:
- drug 1: omeprazole 20 mg po BID
- drug 2: bismuth subsalicylate (525 mg QID)
- drug 3: metronidazole 250-500 mg QID
- drug 4: tetracycline 500 mg QID
33
what is the duration of tx for the bismuth quadruple regimen for tx of PUD d/t h. pylori?
10-14 days
34
given a pt w/ h. pylori, what is another first line combo tx for PUD?
- concomitant regimen
- drug 1: omeprazole 20 mg po BID
- drug 2: clarithyomycin 500 mg po BID
- drug 3: metronidazole 250-500 mg QID
- drug 4: amoxicillin 1 g BID
35
what are the reasons for tx failure in PUD?
- poor compliance
- resistance of h. pylori strain
- clarithromycin resistance
- prior use of macrolide abx, metronidazole, and levoflaxacin increases risk of resistnace
36
what is the approach to salvage therapy when tx of PUD d/y h. pylori has failed?
- abx choice should be guided by pts initial tx
- can increase Bismuth quadruple therapy to 14 days
- levofloxacin triple therapy for 10 days
- high dose dual therapy for 14 days
- last resort: rifabutin therapy
37
levofloxacin triple therapy for salvage tx
- levofloxacin
- amoxicillin
- PPI
- 10-14 days
38
high dose dual therapy for salvage tx
- amoxicillin 1 g TID (or 750 mg QID)
- PPI
- 14 days
39
rifabutin therapy for salvage tx
- rifabutin 150 mg BID
- amoxicillin 1 gm BID
- PPI BID
- 10 days
40
What are the classes of med used to tx n/v
- dopamine receptor antagonists
- 1st generation H1 antagonists
- anticholinergics
- serotonin (5-HT3) antagonists
41
dopamine receptor antagonists
- prochlorperazine (compazine, compro)
| - metoclopramide (reglan)
42
1st generation H1 antagonists
- dimenhydrinate (dramamine)
- promethazine (phenergan)
- meclizine (antiver, bonine)
43
anticholinergics
-scopolomine (transderm scop)
44
serotonin (5-HT3) antagonists
-ondansetron (zofran)
45
ADR of prochlorperazine
- **cardiac arrhythmias (QT prolongation, torsades)
- **extrapyramidal sx
- hypotension
- sedation
- neuroleptic malignant syndrome
46
ADR of metoclopramide (reglan)
- extrapyramidal syndrome
- sedation
- tardive dyskinesia
- acute dystonic reactions
- nausea
- galactorrhea
47
contraindications of metoclopramide (reglan)
- GI obstruction/perforation, concurrent drugs that can cause extrapyramidal syndrome, hx of seizures
- black box warning: irreversible tardive dyskinesia w/ higher dosing and long term use
48
general ADRs of the first generation H1 antagonists
- anticholinergic
- CNS depression
- confusion
- sedation
- constipation
- dry mouth
- urinary retention
- blurred vision
*promethazine: EPS
49
ADRs of scopolomine
- orthostatic hypotension
- zerostomia
- blurred vision
- constipation
- urinary retention
50
ADRs of serotonin antagonists
- QT prolongation (at higher doses)
- contipation
- abdominal pain
- HA
- sedation
- zerostomia
- blurred vision
- fatigue
51
What med classes are used in the tx of constipation?
- stimulants
- stool softener
- osmotic laxative
- bulk forming agents
52
stimulants
- bisacodyl
| - senna
53
stool softeners
-docusate sodium/docusate calcium
54
osmotic laxative
- magnesium salts (hydroxide, citrate)
- sodium phosphates (fleet)
- glycerin (fleet)
- lactulose
- polyethlyn glycol (miralax)
55
bulk forming agents
- psyllium (metamucil)
| - polycarbophil calcium (fibercon)
56
bulk forming agent (psyllium) MoA
soluble fiber that absorbs water in the intestine to form a viscous liquid to promote peristalsis and reduce transit time
57
magnesium salts (osmotic laxative) MoA
-osmotically increases water content of feces and fluid volume in the intestinal lumen resulting in increased intraluminal pressure
which exerts a mechanical force to stimulate peristalsis
58
polyethylene glycol (miralax) (osmotic laxative) MoA
osmotically retains water to produce laxation
59
stool softener/docusate sodium MoA
surfactants that reduce the surface tension and allow intestinal fluids and fatty substances to penetrate the fecal material
60
stimulants MoA
- act as local irritant of intestinal mucosa
- increase propulsive activity
- increase motility by selective action on intramural nerve plexus
- increase mucosal permeability resulting in movement of fluid and electrolytes into intestinal lumen
61
What is the general approach in the tx of constipation?
- good hx is key
- look at all things before starting tx: drug cuases, diseases, lifestyle
- start w/ bulk forming agent
- then can go to osmotic laxative
- can add stimulant or use as rescue
62
what med classes are used in the tx of diarrhea?
- adsorbents:
* bismuth subsalicylate (pepto-bismol)
- opiods:
* loperamide (imodium)
* diphenoxylate/atropine (lomotil)
63
pepto bismol MoA
- bismuth has direct antimicrobial effects and binds enterotoxins
- salicylate component is thought to inhibit intestinal prostaglandin and chloride secretion
- leads to reduced stool frequency and liquidity
64
loperamide (imodium) MoA
- slows intestinal transit
| - enhances water and electrolyte absorption and strengthens rectal sphincter tone
65
diphenoxylate/atropine (lomotil) MoA
-diphenoxylate inhibits excessive GI motility and propulsion
66
What is the appropraite tx regimen to prevent traveler's diarrhea?
- CDC no longer recommends prophylaxis d/t resistance and ADRs
- can be considered in pts at high risk of complications d/t dehydration (IBD, sever vascular, renal or cardiac dz, or immunocompromised)
- non pharmacologic: common sense, avoid ice, certain foods, safe water, "boil it cook it peel it or forget it" and rule of "Ps"
67
What is the tx regiment to tx traveler's diarrhea?
- fluid replacement - important
- restricted diet (clear liquids)
- abx:
* fluoroquinolones
* azithromycin
* rifaxamin
* loperamid w/ abx
* bismuch subsalicylate
68
What med classes are used to provide symptomatic relief of hemorrhoids?
- topical analgesics and steroids: for acute pain and shrinking
- vasoactive agents: reduce swelling
- antispasmotic agents: reduce spasms
- sitz bath: relive inflammation/edema and relax muscles; releive pruritis
- protectants
- astringents
69
role of a low FODMAP diet in IBS
- only one w/ evidence
- eliminate FODMAPs for 6-8 weeks then gradual reintroduction to determine tolerance
- has been shown to improved IBS sx (abd pain, bloating, flatulence and dissatisfaction w/ stool consistency)
70
Given a pt w/ IBS-C, what is the appropriate tx regimen?
1. Fiber: increase in dietary fiber, supplementation, or both.
2. If not responsive to fiber, add osmotic laxative.
3. If 1+2 didn't work, consider lubiprostone (Amitiza) or linaclotide (linzess)
71
Fiber supplementation in IBS-C
- start low then increase dose
- use soluble
- psyllium (metamucil) is preferred
72
Given a pt w/ IBS-D, what is the appropriate tx regimen?
1. dietary modification
2. loperamide (imodium) - needs to be dosed regularly
3. Viberzi - controlled substance, contraindicated if pt doesn't have GB
4. in pts w/ persistent diarrhea despite antidiarrheals, consider bile acid sequestrants
73
What is the max dose of loperamide (imodium)?
16 mg/day
74
What are the meds used to tx pain and bloating in IBS?
- dietary modification
- antispasmodics/anticholinergics:
- dicyclomine (Bentyl)
- hyoscyamine (Anaspaz, Levsin)
