Laxatives and Anti Diarrheal Flashcards
Constipation affects _____ people worldwide
2.5million
____&_____ more likely to complain of constipation but that doesn’t mean
women and elderly
doesn’t mean that they are more likely to suffer from it
Symptoms of constipation
Less than 3 stools a week
Straining
Hard, dry stools
Feeling as though there is incomplete emptying of bowel
Most people who complain of constipation do not actually
suffer from it
Bulk-Forming Laxatives
are used to tx?
how long do they take to work?
constipation
1-3 DAYS
ex: Metamucil, fiber advance
examples of bulk forming laxatives
Psyllium, methylcellulose, polycarbophil
how do bulk forming laxatives work?
Composed of indigestible hydrophilic colloids that absorb water
Forms bulky, emollient GEL
Mechanism: distension of colon triggering peristalsis
side effects of bulk forming laxatives
bloating and gas (because its this bulk gelatenous mass sitting in your gut)– can create more of a problem for constipation
-May prevent absorption of other drugs—don’t want to take them with meds because meds can get stuck in this gelatenous mass and not get absorbed (so 2-3hr separation from other drugs)
Who are bulk forming laxatives good for/not good for?:
Not good for people on opiods– because we stopped a receptor in gut
Good for people with diarrhea or people with “melty poop” soft/loose stools ??
if someone comes in and says “I’m constipated” are bulk forming laxatives the drug of choice?
NO….because it can lead to further constipation and it takes 1-3 days to work.
Stool Softeners known as \_\_\_\_\_\_\_\_\_\_ takes how long to work what is their function? is it a laxative?
surfactants
1-3 DAYS (like bulk forming laxatives)
literally just soften the stool
NOT a laxative
Examples of stool softeners
Docusate (Colace), glycerin, fleet enema
are stool softeners good for people on opioids?
Not good for people on opioids (constipated) because
stool softeners do not increase peristalsis
Good for people with pellet stools
Not a laxative—just a stool softener—can be given with laxative to help someone pass the stool
Do stool softeners cure you of constipation?
Mechanism
Mechanism: soften stool to allow for water and lipid incorporation
Doesn’t really cure you of constipation
Mineral oil is a type of:
what is the deal with it?
stool softener
lubricates fecal material
can tx impaction in kids/adults
not good to take orally anymore because you can aspirate and cause lipid pneumonitis
long term use may impair fat soluble vitamin absorption
Osmotically active agents work to tx
constipation
What are some examples of Osmotically active agents
1) Saline Laxatives (magnesium sulfate, citrate, hydroxide)
2) Nondigestible sugars and alcohols (lactulose)
3) Polyethylene glycol-electrolyte solutions
Osmotically active agents take how long to work ?and how do they fxn?
1-3HOURS
brings water into colon leading to distension and peristalsis
Osmotically active agents–watch out for patients with
Use with caution in patients with renal insufficiency, electrolyte imbalances, cardiac disease, and those on diuretics
Magnesium citrate works like a charm and very quickly if someone is ________-whereas bulk forming laxative would not be the choice.
very constipated (severely constipated)
Nondigestible sugars and alcohols
Lactulose
can be used to tx
chronic constipation from opioids, safe in the elderly, and pts with idiopathic chronic constipation
Nondigestible sugars and alcohols
Lactulose
how to dose?
weird dosing
Given as 15-30ml hs (bedtime)
pt may have some Abdominal discomfort and distension initially but subsides with continued use
- **weird dosing. if you see someone taking lactulose 20-30g 3-4x a day, they are being treated for hepatic encephalopathy
- -it removes ammonia from the gut
Polyethylene glycol-electrolyte solutions
examples of these drugs
**mostly used for
Golytely, Moviprep, Trilyte
colon preps
Polyethylene glycol-electrolyte solutions
OTC version=
Miralax – constipation treatment (OTC version)
**mix with water before using
Stimulant Laxatives
how long do they take to work?
how do they work?
6-8 hrs
not fully understood
example of stimulant laxative:
Bisacodyl (Dulcolax)
when to take it
how long does it take to work
Bisacodyl (Dulcolax) (overnight relief)
Available as a tablet or suppository (suppository works in 30-60 minutes)
Do not use more than 10 days due to risk of developing atonic colon
Often seen in combination with PEG for colonoscopy prep
ex of Stimulant Laxative
Senna (senokot, Ex-Lax)
how do they work? safe? convienent? covered by: long term use?
Gut bacteria converts drug into active form of drug
Safe and covered by medicaid
Poorly absorbed
According to the literature, long-term use does not appear to harm the functioning of the gut nor is it carcinogenic
This drug treats
- chronic idiopathic constipation
- constipation predominant IBS (IBS-C)
- opioid-induced constipation in patients with non-cancer pain
Lubiprostone (Amitiza)
How does Lubiprostone work?
Stimulate type 2 chloride channels (CIC-2) in small intestine increasing chloride-rich fluid secretion into small intesntine
-increased motility
What are a couple downfalls with Lubiprostone (amitiza)
Very poor bioavailability; rapidly metabolized in stomach and jejunum
methadone decreases activity of CIC-2
Not effective when given with methadone
What cytochrome system does lubiprostone use?
none
Lubiprostone (Amitiza) side effects?
dose adjustment?
contraindicated in?
Nausea
Diarrhea
Dyspnea
No dose adjustment in renal impairment; dose adjustment needed in moderate to severe hepatic failure
Contraindicated in obstruction
Opioid Receptor Antagonists are a type of
laxative
Opioid Receptor Antagonists (examples of these drugs)
Methylnaltrexone (Relestor) and alvimopan (Entereg)
Opioid receptor antagonists work well for people who are on opioids…how?
This seems counter intuitive because you are blocking the effects of the opioid, right? No because these opioid receptor antagonists do not cross BBB (so effects of opioid still work to relieve pain)
Important characteristic of Opioid Receptor Antagonists
do not cross BBB
Relestor– type of ?
fxn:
Opioid Receptor Antagonist
sub-q injection for patients with advanced illness receiving palliative care, as well as opioid-induced constipation in patients with chronic non-cancer pain
Entereg type of ?
fxn?
opioid receptor antagonist
capsule approved for acceleration of gut transit time following surgery with partial bowel resection
Restricted to hospital use only and only for 15 doses
Increased risk of MI
In treating diarrhea, what is our biggest concern?
rehydration!!!!
oral rehydration with electrolyte solution =#1 priority
Anti-diarrheal agents main fxn
increase transit time in the gut
the longer you are in the gut, it slows down the poop
in anti diarrheal agents, you should reserve tx for
patients with significant or persistent symptoms
Everyone is stressed gets diarrhea sometimes—don’t need tx all the time
Do not treat patients with anti-diarrheal meds if they present with
high fever
bloody stools
microorganisms in stool
Commonly used antidiarrheal OTCs
Bulk Forming Agents
Bismuth
Loperamide (Imodium) ** most effective
Bulk-Forming Agents
used to tx?
fxn?
does it totally get rid of diarrhea?
antidiarrheal
Modify stool texture and viscosity; patient perception of diarrhea improved
“bulk up” the stool but doesn’t totally get rid of diarrhea
May be useful in occasional mild diarrhea
Bismuth–used to tx?
fxn?
Bismuth- like peptobismal–anti diarrheal
Anti-secretory, anti-inflammatory, antimicrobial effects (can help if theres microbes ex: travelers diarrhea)
Works on abdominal cramping
Useful in traveler’s diarrhea
Loperamide (Imodium)
what type of drug specifically
potent?
anti diarrheal–opIoid AGONIST
~50 times more potent than morphine
Loperamide –how do you use it and not get high?
Does not cross BBB (that’s why you can’t get high off of it –like taking morphine just for your gut
If no improvement in 48 hours, loperamide should be discontinued
Useful in traveler’s diarrhea
Can be used in long term chronic diarrheal disease
Bile Acid Sequesterants are used to tx?
OTC or Rx?
Anti Diarrhea
Rx
Bile Acid sequestrants are good for
Good for patients with malabsorption of bile salts such as those with Crohn’s, or surgical resection of gut
Also bind drugs so require at least 2 hour separation (exception: colesevalam)
Side effects of Bile Acid Sequestrants
Bloating
Gas
Fecal impaction
Examples of Bile Acid Sequestrants
they all have the word ___ in them
Cholestyramine, colestipol (Colestid), colesevalam (Welchol
chole
Diphenoxylate (Lomotil)
Difenoxin (Motofen)
= meds to tx?
Diarrhea
Diphenoxylate (Lomotil)
Difenoxin (Motofen) structurally similar to ______ so it has potential for ______
how to deal with this problem?
Structurally similar to meperidine/demerol, potential for abuse (controlled substance)
-Opioid structure that DOES cross the BBB
So you formulate it with atropine so if someone takes large doses of it, they end up with severe side effects that they won’t like
Constipation and toxic megacolon may result from excessive use of
Diphenoxylate & Difenoxin
Other options to tx diarrhea
Codeine Paregoric (opium tincture) Clonidine Marijuana Colo syrup- brand name emetrol= for people that just become nauseous and we don’t know why they become nauseous
benzos–don’t stop N/V but they relieve the anxiety of someone who is nervous about vomitting/ancitpitory phase.
Clonidine is used in
side effects
Used in diabetic patients with autonomic neuropathy leading to chronic diarrhea
Side effects: hypotension, fatigue, depression
IBD is a ______, ________ chronic, inflammatory condition occurring in the GI tract
idiopathic, immune mediated
two types of IBD
ulcerative colitis, Crohn’s disease
what plays a role in developing IBD?
Genetics, environmental factors, and immune system all play a role
Inflammatory mediators are key
Women are more likely to develop ______
while men are more likely to develop _______
Crohns
ulcerative colitis
Onset of IBD
Onset: 15-30 years old; peaks again from 60-80
