Week 13: GI Meds Flashcards

1
Q

Prototype GI Meds

A

14:

Famotidine
Omeprazole
Sucralfate
AlOH and MgOH
Simethicone
Dimenhydrinate
Promethazine
Metoclopramide
Ondansetron
MgOH
Bisacodyl
Psyllium
Docusate
Loperamide

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2
Q

Famotidine (Pepcid) Classification

A

Antihistamine (H2 Blocking Agent)

different from H1 receptor blockers like true antihistamines

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3
Q

Action of Famotidine

A

Competitive antagonist acting on H2 receptors and mediates parietal cell acid production

Inhibits vagal stimulated gastrin enzyme release

*Basically blocks histamine action at parietal cells in the stomach to stop acid secretion

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4
Q

Routes for Famotidine

A

Oral or Parenteral

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5
Q

ADRs of Famotidine

A

UNCOMMON! (w/ short term use)

CONFUSION (Can see in older individuals since H2 is blocked)

PNEUMONIA

Other: HA, tiredness, constipation

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6
Q

Why is pneumonia a potential ADR of famotidine

A

because increasing gastric pH means organisms that are killed off normally can be aspirated

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7
Q

How often is famotidine given for GERD

A

20-40 mg TWICE DAILY

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8
Q

What does the suffix “-idine” mean

A

H2 blocker

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9
Q

Omeprazole (Prilosec) Classification

A

Proton Pump Inhibitor (PPI), gastric acid secretion suppressent

(Suppresses acid production)

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10
Q

Action of omeprazole

A

a “prodrug” converted to active form in parietal cells

active form inhibits H+K+-ATPase (enzyme producing gastric acid)

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11
Q

ADRs of omeprazole

A

Short Term Use (4-8 weeks): HA, NVD

Long Term: CHRONIC KIDNEY DISEASE, Dementia, Mg Deficiency, Pneumonia, Weakened Bones (Ca absorption)

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12
Q

What is considered to be one of the most effect acid secretion suppression drugs? What is the issue with it

A

Omeprazole

the issue is the ADRs increase with long term use such as chronic kidney disease

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13
Q

What is the most effective class of drugs for suppressing gastric acid secretion

A

PPIs (ex: omeprazole)

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14
Q

What does the suffix “-prazole” mean

A

PPI (ex: Omeprazole, Protonix is Pantoprazole)

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15
Q

What is important to know aboutb the tablet of Prilosec/omeprazole

A

it is enterically coated in a delayed release capsule so do not crush it

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16
Q

Sucralfate (Carafate) Classification

A

Anti Ulcer

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17
Q

What is unique about sucralfate

A

it is a unique drug with no other drug being like it

It “patches” the ulcerated area in the stomach mucosa

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18
Q

Action of sucralfate

A

exact mechanisms not fully defined

exerts LOCA ACTION - forms an ULCER ADHERENT COMPLEX (gooey sticky patch) at the ulcer site to protect it against further acid attack, pepsin, or bile salts

Also inhibits pepsin activity

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19
Q

Where does sucralfate act

A

acts locally (on the GI tract) not the bloodstream by patching the ulceration on mucosa

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20
Q

Sucralfate must be given…

A

on an empty stomach

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21
Q

What is important to know about the absorption and distribution of sucralfate

A

only 3-5% is absorbed since it has local low absorption

It is distributed on the GI tract and lasts about 5 hours

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22
Q

ADRs of Sucralfate

A

Most Common: CONSTIPATION

Other: Diarrhea, Nausea, Gastric Discomfort, Indigestion, Dry Mouth, Rash, Pruritis, Back Pain, Dizziness, Vertigo

*generally well tolerated)

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23
Q

Why can sucralfate not be given with an antacid within a half an hour period

A

because the stomach mucosa needs to be pH <4 for activation

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24
Q

sucralfate may interfere with what

A

absorption of fat soluble vitamins (blocks that mucosa)

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25
Antacids
base salts that increase gastric pH by doing so, they relieve symptoms of hyperacidity, GERD, and the pain of duodenal ulcers
26
AlOH & MgOH (Maalox) Classification
Antacid, Non sytemic
27
When do we give antacids
2 hours after other drugs to prevent interactions Also given after meals WHEN ACID IS ALREADY PRODUCED
28
Action of AlOH & MgOH (Maalox)
local activity of neutralization of gastric acid by chemical reaction leading to higher pH
29
Absorption of AlOH & MgOH (Maalox)
it is not absorbed AT ALL
30
ADRs of AlOH & MgOH (Maalox)
Aluminum products cause constipation Magnesium products cause diarrhea Maalox attempts to balance these two effects out
31
What is important to know about taking other drugs alongsde AlOH & MgOH (Maalox)
the maalox can reduce absorption of drugs like tetracyclines, digoxin, iron, etc so they are all taken separately from antacids
32
Simethicone (Mylicon) Classification
anti flatulent
33
Action of simethicone
alters surface tension of gas bubles - they then coalesce and free the gas through belching or flatus Disperses and prevents formation of mucus surrounded gas pockets in the GI tract so its easier for the body to expel these big bubbles
34
In essence what is simethicone doing
it is not PREVENTING gas from being made, it just is finding new ways of epelling it
35
ADRs of simethicone
VERY WELL TOLERATED so mild it can be used on infants (can help with colic)
36
Route of simethicone
oral (80-120 mg qid)
37
Is simethicone often found in combination with anything else
its often found combined with other GI drugs like antacids
38
Why is simethicone the last drug you should take
because it works faster in dissolving than other drugs since its pink and chewable
39
dimenhydrinate (Dramamine) Classification
ANTIEMETIC, Anticholinergic, Antihistamine
40
What is dimenhydrinate often used for
PREVENTION of motion sickness
41
Action of dimenhydrinate
decreases GI motility and GI spasm (that usually causes vomiting) due to its anticholinergic action Some H1 - antihistamine action affect neural labyrinth pathways by competing for receptor sites
42
ADRs of dimenhydrinate
ANTICHOLINERGIC SE - Dry mouth Sedation Blurred vision Urinary Retention (slow GI effect)
43
When should dimenhydrinate be taken
take .5-1 hour before activity like a car ride, boat ride, coaster, etc - it should be on board and working prior for prevention
44
dimenhydrinate is contraindicated when
if a patient has glaucoma as it increases intraocular pressure
45
What is a problem that dimenhydrinate may mask
It can mask ototoxicity symptoms if the patient is on other drugs since it is chemically related to diphenhydramine (Benadryl)
46
Promethazine (Phenergan) Classification
Antiemetic (Phenothiazine family)
47
What is the phenothiazine family structurally similar to
anti psychotic drugs
48
Action of Promethazine
Acts on the CTZ (Chemorecetor trigger zone) / Vomiting center by interacting with dopaminergic receptors to suppress the response
49
What is important to know about the absorption and route of promethazine
It is given oral NEVER IV It has almost complete absorption
50
why is promethazine never given IV
it can cause severe necrosis of tissues and blood vessels
51
ADRs of promethazine
1. PERIPHERAL ANTICHOLINERGIC EFFECTS (dry mouth, constipation, blurred vision, urinary retention) 2. Sedation, Hypotension, Dystonia - unusual muscular activities
52
Is promethazine effective for motion sickness
no
53
Why is promethazine commonly given in conjunction to narcotic therapy
it has a synergistic effect for analgesia with narcotic and non narcotics
54
Metoclopramide (Reglan) Classification
Antiemetic
55
Action of Metoclopramide
Blocks dopaminergic receptors in CTZ/Vomit Center including antagonism of emesis Stimulates AcH effect to enhance motility of smooth muscles from the esophagus to the small intestine Accelerates gastric emptying and transit of intestinal contents from duodenum to ileocecal valve
56
ADRs of Metoclopramide
1. CNS - drowsiness, dizziness, ANXIETY, RESTLESSNESS 2. Extrapyramidal symptoms esp with high IV doses (nystagmus, pill rolling, tongue movement) GI - constipation, nausea, diarrhea, dry mouth Endocrine - gynecomastia
57
Metoclopramide is considered what kind of agent
a Pro Motility agent - it stimulates GI because of its AcH stimulating effect
58
What does it mean for metoclopramide to be pro acetylcholine
it is a GI stimulant it will boost motility while there is no NV like in diabetic gastroparesis (early satiety) and give pro motility effects before eating to prevent vomiting
59
Why is it important to never mid metoclopramide (or phenergan) with a CNS depressant
metoclopramide has a sedative nature already
60
When should metoclopramide be administered
30 minutes prior to meals
61
Metoclopramide is highly effective with what sort of agents
highly emetic anti cancer agents
62
When is metoclopramide contraindicated
in the presence of : obstruction (pressure against the wall leading to perforation) hemorrhage perforation of the GI tract
63
Ondansetron (Zofran) Classification
anti emetic / selectric serotonin receptor antagonist
64
Action of ondansetron
selective serotonin 5HT3 receptor antagonist - NOT a dopamine receptor agonist like other anti-emetics blocks stimulation of serotonin receptors in CTZ to prevent NV - not very well understood
65
What drug has replaced Phenergan and Reglan
ondansetron (Zofran)
66
Is odansetron for prevention only?
no- it mostly is for preventing NV but it can be given IV for vomitting episodes
67
Routes of Absorption for odansetron
IV for episodes oral for prevention
68
Distribution of odansetron
widely distributed - including ending up in breast milk However, 70-75% of it will be protein bound
69
ADRs of odansetron
TRANSIENT BLURRED VISION (only IV form) Other: Constipation, Rashes
70
Doses of odansetron are based on ...
weight
71
Odansetron is especially effective with what unique NV situations
chemotherapy induced NV post - op NV anticipatory NV - smells or thoughs from chemo that trigger it
72
When is odansetron given in reference to chemotherapy treatment
it is given 30 minutes prior
73
What is the one kind of NV that odansetron cannot prevent
CINV - chemo induced NV which is a delayed form of vomiting from the chemo Emend - another drug - does however
74
Cathartic
Laxative
75
Magnesium products cause
diarrhea
76
Magnesium Hydroxide Mixture (MgOH) - Milk of Magnesia (MOM) Classification
Saline Cathartic (Laxative)
77
Action of MgOH/MOM
In the stomach it reacts with HCl to form Magnesium Chloride which causes the laxative effect Water will be retained in the bowel causing peristalsis - and this water is pulled from the intestinal lumen
78
Absorption of MgOH/MOM
Almost none is absorbed - maybe only a small amount from the intestine
79
Distribution and Onset of MgOH/MOM
onsert is .5-3 hours SO THEY MUST HAVE ACCESS TO A BATHROOM
80
ADRs of MgOH/MOM
Occasionally Diarrhea (mostly with more than 1 use a day) MAY have absorption of ions and cause imbalance of Mg (only a problem with renal impairment as it accumulates)
81
Can MgOH/MOM be used on children
yes it is a very mild saline laxative
82
while MgOH/MOM is the mildest saline cathartic, what must be kept in mind while taking it
to avoid fluid imbalance, adminsiter with large amounts of water caution in renal failure
83
Polyethylene Glycol
Miralax Used for chronic constipation - a nonabsorbable compound that retains water in the intestinal lumen like a saline cathartic like MOM/MgOH However, takers 2-4 days potentially for a BM
84
What is used prior to a colonoscopy
polyethylene glycol and electrolytes for bowel cleansing
85
Is laxative dependence proven
it is not proven by researchers
86
bisacodyl (Dulcolax) Classification
Cathartic, Stimulant (or contact)
87
Action of Bisacodyl
stimulates peristalsis by 1 of 3 ways: 1. Stimulating nerve plexus 2. irritating mucosa 3. direct action on smooth muscle *Comes into contact with mucosa to cause peristalsis
88
Route of Bisacodyl
1. Rectal Suppository 2. Enteric Coated Tablet (Oraal)
89
ADRs of Bisacodyl
1. Suppository MAY produce mild burning sensation in rectum (irritation of mucosa and its not pain) Other: Intestinal Crampes, increased mucus secretion, diarrhea
90
What is important to know about the oral form of bisacodyl
do not give oral tablet with antacid or milk and do not cut, crush, or chew the tablets (they are v small to prevent this)
91
Psyllium (Metamucil) Classification
Laxative, Bulk Forming Agent (it is a fiber supplement more than a cathartic - not a true cathartic)
92
Action of psyllium
absorbs water (fiber), enlarging bulk of fecal mass This mass mechanically stimulates the bowel and promotes formation of soft, water retaining gelatinous residue in the lower bowel in 12-72 hours
93
How do fiber supplements like psyllium differ from true cathartics
fiber supplements dont work right away - they get you more regular so they take time to work and keeps things moving through the GI tract and adds bulk
94
Why does psyllium need to be drank immediately
it comes in a powder form that you mix in liquid and drink immediately it thickens like oatmeal quick so you have to drink asap also does have a capsule and wafer form
95
ADRs of psyllium
RARE
96
Sodium Docusate (Colace) Classification
emollient agent (stool softener)
97
Action of Sodium Docusate
acts as a detergent and allows water and fatty substances to penetrate and mix well with fecal material It is an emollient by mixing the water with stool to soften the mass, but does not cause bowel movement right away
98
How does sodium docusate differ from cathartics and fiber supplements
it does not make you have to go, but rather when you do it is softer
99
ADRs of sodium docusate
negligible, but occasional diarrhea
100
What is a special caution with sodium docusate
may promote absorption of mineral oil (a fat) if given concurrently
101
Loperamide (Imodium) Classification
antidiarrheal
102
Action of loperamide
structurally similar to the opioid meperidine So, it suppresses bowel motility and fluid secretion into the intestinal lumen by binding gut wall opioid receptors this stops them from going
103
What is a real life situation when loperamide may be helpful
when travelling incase of water induced diarrhea
104
ADRs of loperamide
1. CONSTIPATION Other: Nausea, Abdominal Cramps, Dizziness, Drowsiness
105
Black Box Warning of loperamide
TORSADES DE POINTES (only at higher than normal doses) It is a very serious life threatening cardiac rhythm
106
Why can torsades de points be a big problem with loperamide
because loperamide is available OTC and is not controlled
107
Lotomil
an antidiarrheal similar to loperamide it is diphenoxylate (opioid) plus atropine The opioid will stop diarrhea but the atropine will discourage opioid abuse because the atropine will make you miserable before an opioid high
108
You are helping a home care client schedule her medications. When would be the most appropriate to receive a proton pump inhibitor? A. At Night B. After fasting at least 2 hours C. About 30 min before a meal D. About 2-3 hours after eating
C. about 30 min before a meal
109
Your patient is ordered to receive MgOH for post op constipation. What would you assess first? A. BP B. Bowel Sounds C. The patient's ambulatory status D. Patients Mg Levels
C. The patients ambulatory status (so when they do have to go they get there safely - bowel sounds are good but not the point)