Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PDAT2 > 27 - GI Pharmacology > Flashcards

27 - GI Pharmacology Flashcards

1
Q

Gastric Secretion

A

Acid is secreted from
Gastric Parietal Cells
stimulated by:
Histamine / Acetylcholine / Gastrin
which all share a final-common pathway:
activate H+/K+ ATPase Proton Pump

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q
  • *Prostaglandin E2 & E2**
  • *Function**
A

INHIBIT ACID

Stimulate Secretion of:
Mucus & Bicarbonate

DILATE mucosal blood vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

REDUCE INTRAGASTRIC ACIDITY

Pharmacological Mechanisms for treating PUD

A

Block Gastric Acid secretion
multiple mechanisms

  • *Neutralize Excess Gastric Acid**
  • *antiacids**
  • *Eradicate H.Pylori**
  • *antimicrobials**
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

PROMOTE MUCOSAL DEFENSE
Pharmacological Mechanisms for treating PUD

A
  • *Repair Mucosal Barrier Breakdown**
  • *Cytoprotectants**

Prostaglandin-Stimulated Cytoprotection
Prostaglandin - analogs
ALSO reduce gastric acid secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

H2RA
MoA

-tidine

A
  • *Competitive Antagonist of H2 Receptor**
  • virtually NO h1 Antagonist*

Inhibit GASTRIC ACID secretion
from Histamine / Analogues / Food
reduce:
Volume of GA secretion / H+ concentration
Gastrin / Pepsin / IF secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

H2RA
ADR / Side Effects

-tidine

A

Cimetidine = many DI’s

Usually MINOR side effects

Microorganisms
from BASIC/hypoChloridic Stomach

Bradycardia –> Rapid IV, not usually givin IV though

CNS-Mental Confusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q
  • *PPI**
  • *MoA**
A

PRODRUG
needs acidic environment –> absorbed in intestine
forms Disulfide bridge w/
H+ /K+ -ATPase Enzyme
Proton Pump
VVVVV
Decrease Gastric Acid Secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

PPI
ADR’s

A
  • Relatively MINIMAL side effects:*
  • HA / Nausea / Diarrhea / Ab pain / Rash*

Potential for mucosal hyperplasia

  • *Concerns about LONG TERM use**
  • *Dementia?**
  • *rebound HYPERacidity** –> TAPER OFF

DI’s –> other drugs that decrease acid secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • *CNS ACTIVE**
  • *Anti-Muscarinics**
A

ATROPINE

SCOPOLAMINE

CNS ​inactive
probantheline / methscopolamine / glycopyrolate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Antimuscarinics
Scopolamine / Atropine

MoA

A

Block M1 & M3 Cholinergic Receptors
M1 –> histamine containing paracrine cells
M3 –> on parietal cells
most are non-selective

do NOT totally inhibit gastric acid secretion
LEAST effective class of antisecratory agents
usually used in tandem / with another drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

AntiMuscarinics
Scopolamine / Atropine

ADRs

A

Peripheral PARA-Sympatholytic Activity
Tachy Cardia // Constipation // Blurred Vision
drying/slowing

  • *CNS** if it crosses BBB
  • *sedation / memory disruption**
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Types of Antacids

A

SCAMM
Systemic –> bloodstream​
•Sodium bicarbonate
•Calcium bicarbonate

non-systemic –> poorly absorbed from intestine
•Aluminum hydroxide
•Magnesium hydroxide

•Magnesium trisilicate/Aluminum trisilicate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Antacids

MoA

A

CHEMICAL NEUTRALIZATION of Gastric HCL

RAISE pH of stomach contents
thereby
decreasing acid load –> to duodenum
& reducing PEPSIN activity

FAST ACTING // Short duration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Systemic Antacids

A

Sodium Bicarbonate >> Calcium Bicarb

Are ABSORBED –> BLOODSTREAM
so they have a potential to:
Increase blood pH & alkalinize URINE

hazardous if used chronically
days - weeks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Non-Systemic Antacids

A

Mg & Al
Hydroxide

POORLY absorbed from SMALL INTESTINE
so they are NOT
likely to alter BLOOD / URINE pH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Misoprostol = Cytotec

Class // MoA

A

Prostaglandin Analog
synthesized in GI mucosa –> reduce gastric acid production by:
inhibiting AC synthesis of cAMP
Stimulate secretion of mucus = Cytoprotectant

Used WITH NSAIDS to Prevent ULCER Formation
NSAIDS –> inhibit produciton of PG’s & cause ulcers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Prostaglandin Analog
Misoprostol = Cytotec

ADR

A

GI Cramping & Diarrhea
increased secretory activity –> accumulation of fluid in bowel

  • *Increases UTERINE CONTRACTIONS
  • NOT FOR PREGNANT WOMEN***
18
Q

Sucralfate = Carafate

Class // MoA

A

CYTOPROTECTANT
Al-Sucrose-Sulfate
Basic –> @pH 4 –> polymerizes to from a viscous gel

  • *Complexes w/ proteins** on ulcer surface to form a
  • *PROTECTIVE LAYER** against:
  • *HCL / PEPSIN / BILE**

inhibits PEPSIN activity & absorbs BILE ACIDS

19
Q

Cytoprotectant
Sucralfate = Carafate

PK & Uses

A
  • POORLY Absorbed from GI TRACT*
  • *GOOD = want to COAT**, not absorb

6-12 hours

Increases rate of PEPTIC ULCER HEALING

efficacy is comparable to H2RA’s

20
Q

Bismuth Subsalicylate = Pepto Bismol

MoA

A

Binds to an ulcer base –> providing Protective Coating

INCREASES SECRETION of:
Prostaglandin // Mucus // BiCarbonate

  • REDUCES H. PYLORI*
  • *antimicrobial**
21
Q

Bismuth Subsalicylate

ADR

A

very FEW serious side effects

SALICYLATE concerns

STAINS –> difficult to remove

22
Q

Gut Absorption Process

A

Normal gut absorption is dependent on the
BALANCE of:
Absorption // Secretion
of Water & Electrolytes

  • *Small Intestine = 80% of fluids**
  • colon absorbs the rest*
23
Q

Antigrade Motility of GI Tract

A

SLOWER Transit –> GREATER FLUID ABSORPTION

Faster Transit –> less fluid absorption

24
Q

Types of ANTIDIARRHEALS
& Goals

A

INCREASE water&electrolyte Absorption from the gut
by decreasing GI motility –> INCREASES transit time

Opiates

Bismuth

Gel-Forming Substances

Antimuscarinics

5-HT Antagonist

25
Q

Opiates that do NOT cross the BBB
Anti-Diarrheals

A
  • *LOPERAMIDE**
  • *Imodium**
  • *Diphenoxylate + Atropine**
  • *Lomotil**
26
Q

Loperimide & Diphenoxylate+Atropine
Opiates that do NOT cross the BBB

MoA

A
27
Q

Increase SEGMENTAL CONTRACTIONS
of both small/large intestines
but this is NON-Synchronized –> slows down movement
in turn Increasing ABSORPTION

Decrease Secretion of FLUID & E- into lumen

CNS-Active
increase transit time & accumalation of fluid in lumen via CNS sites

A
28
Q

Kaolin + Pectin

MoA / Drug Class

A

GEL-FORMING SUBSTANCE
for Diarrhea

MoA:
forms a clay-like gel when hydrated
which PROMOTES stool formation
adsorbs:
toxins / bacteria / absorbs fluid

29
Q

Issue with
ANTIMUSCARINICS + OPIATES

A

DO NOT WANT TO PATIENTS TO TAKE A LOT OF THESE

if you SLOW down GI activity with these drugs
you run the risk of the
PATHOGEN ENTERING THE BLOOD STREAM

30
Q

Antimuscarinics as Anti-diarrheals

Drugs // MoA

A

Dicyclomine // Propantheline // Hyoscyamine

MoA:
reduce GI MOTILITY

reduce SECRETIONS
by inhibiting parasympthetic impulses

31
Q

Alosetron (Lotronex)

Drug Class / Use / MoA

A

5-HT3 Antagonist
for IBS w/ DIARRHEA

  • *GI 5-HT Blockade**
  • inhibits* unpleasant visceral sensations = Nasuea/bloating/pain
  • inhibits* colonal motility –> increased transit time
  • CNS 5-HT receptor inhibition*
  • REDUCES* brain response to visceral afferent stimulation
32
Q

Constipation

mainly an issue in
Babies & Elderly

A
  • *SYMPTOM**
  • not a disease*

Characteristics:
caused by host factors
size / frequency / consistency of bowel movements are
HIGHLY VARIABLE
often caused by dehydration of feces that stay too long in colon

33
Q

Laxative
CLasses & Drugs

A
  • *Chloride Channel Activator**
  • *Lubiprostone** = Amitiza
  • *Guanylate Cyclase C Agonist**
  • *Linaclotide** = Linzess

Dietary fiber & bulk-forming laxatives
Psyllium (Metamucil)

Osmotic laxatives
MoM // Golytely PEG

Stimulant laxatives (Cathartics)
Bisacodyl = Dulcolax

**_Emollient laxatives (Stool softeners)_**
Docusate sodium (Colace)
34
Q

How do LAXATIVES promote Defacation?

A

RETENTION of Fluid in colonic contents

reduction in NET absorption of WATER & NaCl

INCREASED Intestinal Motility

35
Q
  • *Psyllium** = Metamucil
  • *Methylcellulose** = Citrucel
A

BULK-FORMING LAXATIVES

Whole Grains // Fruits // Veggies
are similar
act as DIETARY FIBER

36
Q

Bulk-Forming Laxatives

MoA // ADR

A

Increase in

  • *Fecal MASS** // Rate of Colonic TRANSIT
  • *Water Content of feces –> form Bulky / Emollient gel**

Soften feces in 1-3 days
Relief of symptoms of CHRONIC DVT

ADR:
Gas / Bloating / Ab discomfort

37
Q

Osmotic & Saline Laxatives

Drugs / MoA / ADR

A

Magnesium Sulfate & Hydroxide
Epsom Salt // Milk of Magnesia

Osmotic Pressure –> retain water in colon

Sodium Phosphates = Fleet
stimulate secretion of cholescytokinin –> secretion & motility

ADR:
INCREASED Mg Salt absorption
Electrolyte Disturbances

38
Q

PEG Electrolyte Solution
NonAbsorbable Sugars

MoA // Class / ADR

A

Osmotic Laxatives

  • *Accumulation of Fluid** in LUMEN
  • *watery evacuation
  • -> 1-3 hours**

ADR:

  • *Flatulence & abcramps**
  • *N/V**
39
Q

Stimulant Laxatives

Drugs // MoA

A

Bisacodyl** // **Danthron** // **Castor oil
diphenymethane // senna(anthraquinone) // ricinoleic acid

INCONSISTANT EFFECTS
act DIRECTLY to stimulate colon
–> enteric neurons & GI smooth muscle

Soft or semisolid stool in
6-8 hours

40
Q

Emollient Laxatives = Stool Softeners

Drugs // MoA / ADR

A

Docusate Sodium** // **Lactulose
Colace

Stool softener by incorporating water –> fatty fecal matter
Surfactant = soap

Softens feces
in 1-3 days

ADR:
Nausea + AbCramp

41
Q

Lubiprostone = Amitiza

A

CHLORIDE CHANNEL ACTIVATOR
for CHRONIC CONSTIPATION

MoA
Specifically activates Cl- Channels in gut
Increases liquid secretion –> intestines
shortens Intestinal TRANSIT TIME

42
Q

Linaclotide = Linzess

A

GUANYLATE CYCLACE C AGONIST
used for CHRONIC Constipation

a poorly absorbed 14 AA peptide
MoA:
Binds to Guanylate Cyclace C receptor on GUT Enterocytes
activates cystic fibrosis transmembrane conductance channel
stimulates intestinal fluid secretion

PDAT2 (22 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions