Constipation Flashcards
True or false: the poor quality of life that is experienced from constipation is comparable to osteoarthritis and diabetes
true
Describe the physiology of the gut.
interplay of intestinal smooth muscle
-parasympathetic stimulates motility
-sympathetic inhibits motility
-GI hormones
-serotonin (90% of serotonin is in the gut)
-CNS (ex: emotions)
gastro-colic reflex
What is the gastrocolic reflex?
physiological reflex that controls the motility of the lower GI tract following a meal
as a result, the colon has increased motility in response to the stretch of the stomach with the ingestion of food
What is “normal” BM activity?
wide range: 2x per week to 3x per day
What is the normal flora of the gut?
lactobacillus
bifidobacterium
saccharomyces
Describe fluid recovery in the gut.
9L of fluid enters duodenum per day
-2L from diet and 7L from intestinal secretions
approx 8L absorbed by small intestine
large intestines absorbs about 850ml
about 150ml excreted in stool/day
What is the etiology of constipation?
not a normal part of aging but aging comes with:
-disease states
-drug causes
-immobility
-fluids (maybe)
True or false: constipation only means passing infrequent stools
false
could also mean hard stools or sense of incomplete emptying after a bowel movement
What is a good question to always ask in a constipation counsel?
whats normal for you?
What are some complications of constipation?
hard stools
anal fissures
rectal bleeding
hemorrhoids
What is the most common pattern of bowel movement?
one bowel movement per day
this pattern is seen in less than 50% of people
True or false: in the majority of cases, constipation is harmless
true
Is pain a characteristic symptom of constipation?
not really
if pain consistently enters the equation, start thinking another cause such as IBS
What should be kept in mind for differential diagnosis when you are doing counsel surrounded around bowel movements?
medication-induced constipation
diabetes
colon cancer
IBS
depression
How many days without a bowel movement is concerning for us?
3 days or more
What are the red flags for constipation?
changes in stool texture
blood in stool
hemorrhoids
weight loss
decreased appetite
nausea and vomiting
frequent pain
narrower stools
unresponsive to treatments
For someone who has been experiencing lingering constipation, what is the time frame at which they should seek an MD?
three weeks or more
the context is constipation, not the lack of BM for 3 weeks
What is the answer to how long is too long for constipation?
depends on how often they poop in the first place
add more clinical symptoms=refer faster
What is a large bowel obstruction?
part or all of the large intestine is blocked
waste cant move through the bowel properly and out of the body
What is the most common cause of a large bowel obstruction?
a growth or tumor that blocks the intestine such as cancer
What are the symptoms of large bowel obstruction?
cramping and pain
swelling and bloating
unable to pass gas
constipation
vomiting
more than normally seen with simple constipation or IBS-C
How much fiber does a woman need per day? What about men?
women: 25g
men: 38g
At what speed should fiber be added to someone’s diet?
add it slowly
Which fiber is given credit for better effect on BM?
insoluble fiber
True or false: the majority of Canadians consume the recommended amounts of fiber
false
What should someone expect as a side effect when they start adding more fiber to their diet? How much should fiber be added when increasing your intake?
gas
go slow, increase by up to 5g/day
How much fiber is in the following: granola bars, cashews, apple, bran flakes, bran muffin
granola bars: 1g
apple: 3g
cashes (1/4 cup): 1g
bran flakes (3/4 cup): 5g
bran muffin: 4g
What is bowel re-training?
re-establishing the gastrocolic reflex
-defecation stimulation post meal
finding the best time for BM
more applicable to the nursing home world
Are prunes a natural laxative?
prunes contain sorbitol which has a laxative effect
prunes contain insoluble and soluble fiber
if it worked quickly, it was due to the sorbitol
How many prunes should be given to adults if they are considering it for constipation?
prunes: start with 4
prune juice: start with 1/2 cup
What are the agents of choice for prevention of constipation?
bulk-forming agents
True or false: bulk-forming agents are insoluble fiber
false
soluble fiber
What are the bulk-forming agents?
psyllium
polycarbophil
guar gum
wheat dextran
inulin
methylcellulose
bran
What is the MOA of bulk-forming agents?
swell in intestinal fluid–>creates gel–>facilitate passage
What are the expectations to provide with bulk-forming agents?
usually takes a few days (2-3)
patient preference for taste
needs fluids (240ml water)
not easy to swallow sometimes (not ideal if strong gag reflex)
How should psyllium be taken when first starting?
1 serving each day, as you adjust you can increase to 3 servings per day
- >12yrs:one tsp (7g) in 240ml water
- 6-12yrs: 1/2 tsp (3.5g) in 240ml water
- <6yrs: do not use
start with BID
Who shouldnt take the flavoured versions of psyllium?
diabetics
the flavoured versions have sugar
True or false: psyllium-induced obstruction is fairly common
false
extremely rare
What are the symptoms of psyllium-induced obstruction?
pain/cramps/nauseous
can maybe feel a mass
no fecal output
diarrhea (there can be some leakage)
True or false: inulin is more effective than psyllium
false
psyllium is more effective
Differentiate between psyllium and inulin.
psyllium:
-more effective
-thickens
-OD to TID
-mix with H20
-lowers cholesterol (5%)
inulin:
-much more palatable
-non-thickening
-OD to TID
-can add to fluid or food
-less cholesterol effect
True or false: psyllium capsules are not a good choice as you must take lots of capsules each day (6-8)
true
How long should someone use psyllium for?
try for a month and then re-assess
can use it forever
What is an example of a stool softener?
docusate
How does docusate work?
anionic surfactant
=better mixing of aqueous and fatty compounds to soften the fecal mass
In what manner is docusate commonly used?
prevention
common on maternity wards and with palliative care
added to other laxatives (for the “gentle touch” marketing)
What does the efficacy of docusate benefit from?
efficacy benefits from increase in water
How long does it take for docusate to work?
1-2 days (up to 3-5 days in some)
What is the adult dose of Colace (docusate)?
1-2 caps per day
4 caps per day in nursing homes
up to 8 caps in palliative care
What is the reputation of docusate?
not a strong agent or maybe not even effective at all
probably because of underdosing
What is a contraindication of docusate?
use with mineral oil
What is a lubricant used for constipation?
mineral oil
How does mineral oil work for constipation?
softens fecal matter by “coating it”
What are the main problems of mineral oil for constipation?
anal seepage
lipid pneumonia (esp when lying down so avoid HS dosing)
Does mineral oil decrease the absorption of fat soluble vitamins?
no
would have to be taken at the same time as food for this to occur but we eat multiple times a day so its not an issue
What should the patients expect with mineral oil for constipation?
orally takes about 6-8 hours
mineral oil enema (Fleet) works very quick
What are some products that have attempted to make mineral oil taste better?
Agarol (agar + MO)
Magnolax (MgOH + MO)
Lanosyl (MO jelly)
What is the difference between heavy vs light mineral oil?
heavy has less chance of sticking to throat and better at sticking around GIT
What are saline (osmotic) laxatives?
non-absorbale ions (ex: Mg citrate, MgOH)
remains in the gut–>highly osmotic–>draws water in
What are the indications for osmotic laxatives?
bowel evac for exams (Citro-Mag, PicoSalex)
bowel evac for acute constipation (Fleet enema)
general use (ex: overnight relief)
In which patients should osmotic laxatives be used carefully?
patients with congestive heart failure and chronic renal insufficiency
How fast do osmotic laxatives work?
Philips: overnight treatment
Fleet enema: 2-5 minutes
What is the youngest age we are comfortable giving an enema to?
2yrs is the youngest for an enema
How do glycerin suppositories work?
osmotic effect and a local irritant effect
in infants, just the mass can lead to defecation
What is the agent of choice for constipation for very young kids?
glycerin suppositories
How fast do glycerin suppositories work?
bowel evac within 30 min
True or false: oral lactulose reaches the colon virtually unchanged
true
How does lactulose work?
in the colon–>bacteria–>lactic acid–>osmotic pressure–>increase stool volume
What is the dosing for lactulose?
15-60ml OD
works in 1-2 days
What is the main side of lactulose?
gas/bloating
Is lactulose safe in diabetics?
yes
What is the use of PEG 3350?
prevention therapy
How long does PEG 3350 take to work?
a few days
What is the dosing of PEG 3350?
start with one capful (17g), then titrate q2-3 days by 25% to achieve mushy stool consistency
dissolves completely in fluid
How many days should PEG 3350 be used for?
label states use <7d unless MD
What is the age use for PEG 3350?
not for kids <18 unless MD
What are all the non-saline osmotic laxatives?
glycerin supp
lactulose syrup
PEG 3350
What is the MOA of stimulant laxatives?
irritant to gut lining
What is the onset of action of stimulant laxatives?
6-12 hours (overnight)
What are the side effects of stimulant laxatives?
diarrhea and cramps if too much is given
-an effective dose for one person could see cramps for another
bisacodyl and senna are minimally absorbed
What is the name of the historical stimulant laxative?
phenolphthalein
What is the old thinking regarding stimulant laxative overuse?
cathartic colon occurs with chronic use of stimulant laxatives (>3 times per week for at least 1 year)–>atonic colon
when the drug is dc, changes in the colon may partially return to normal because of drug-induced damage to the colon
the new thinking suggests this is not true
What is the dosing for senna?
8.6mg: 2-4 tabs OD-BID HS
-HS not needed, go for 8am and 7pm
17.2mg: 1-2 tabs OD-BID HS
-same comment as above
What is the dosing for bisacodyl?
suppository: one supp per day
-onset in 15-60min
tabs: 1-2 tabs daily
-onset: 6-12 hours
How should we start the average patient on senna?
start around 8mg
make adjustments each night thereafter
How is senna used for a patient on T3s?
if T3 started late in day–>8mg first night
if T3 started early in day–>16mg first night
can make adjustments each night thereafter
True or false: use senna if its been 3 days with no BM when using preventive agents
true
Does it make sense to use Senokot S as prn use?
no
the docusate will just be going along for the ride because its underdosed
Why was castor oil put behind the counter?
was being used as an abortifacient
could spark contractions and premature labour
What are microlax enemas?
physical + chemical rx with fecal matter
5ml dose–>evacuation in 5-20 min
nursing home use is common
Describe Colyte (PEG).
used for pre-colonoscopy
has added electrolytes
drink 240ml q10min–>4L
expect 1 BM within first hour
What is lubiprostone used for?
management of chronic idiopathic constipation
predominantly IBS associated constipation in women and opioid-induced constipation
What is the role of probiotics in constipation?
nobody really knows
would be more so for prevention, not acute needs
What are the non-pharm measures to try prevent constipation in the elderly?
dietary efforts preferred over meds
-bran for prevention, prunes for acute needs
exercise (iffy value esp for seniors)
fluid intake (iffy value)
What are the red flags for elderly and constipation?
unexplained new onset/worsening
-a new med could be considered an “explained” onset
blood in stools
weight loss, anorexia
fever
nausea and vomiting
family history of colorectal cancer
What is normal BM for infants?
1 BM per each feed to 1 per week
breast feed ~3 a day
formula ~2 a day
What are the common causes of constipation in paeds?
starting solid foods
enough fluids
medical causes are rare
What is our process for constipation with infants?
always have MD referral in mind
rectal stim (Q tip with vaseline)
-1/4 inch and run it around ring of the rectum in a circular motion for up to 5 min
glycerin suppository
What are the reasons for constipation in children?
too busy to poop
dietary issues
toilet training issues
-stool lifts can help with propulsion
with-holding behaviour
-family conflict, anal fissures, bathrooms in strange places
What is the formula for fiber amount for kids?
age + 5=g amount
True or false: there are many suppositories that are contraindicated in kids
false
almost all are fine
Which laxative is a great choice for prevention of constipation in kids?
PEG 3350
start with 1/2 capful, then titrate
What is the main goal with treating constipation in kids?
soft stool each day
a child may need to take this medication for a long period of time (often up to 4-6 months)
dont make too many changes based on a single stool
How much do we decrease the dose of a laxative if the child is having regular loose stools or diarrhea?
25%
What percentage of pregnant women experience constipation?
~50%
If a woman is experiencing constipation during pregnancy and believes that her iron is to blame, is it our call to stop the iron?
no
Why are laxatives safe in pregnancy?
they have minimal systemic absorption
therefore they are not expected to be associated with an increased risk of congenital abnormalities
Which laxative is very common in pregnancy?
docusate
Do MoM, senna, or bisacodyl pose a birth defect concern?
no
uterine contraction concern? yes
True or false: diabetics would have less constipation than non-diabetics
false
What is the most common adverse effect with chronic opioid use?
opioid-induced constipation
-41 to 90% of users
True or false: lowering the dose of an opioid will improve constipation
false
Does tolerance develop to opioid-induced constipation?
no
What is a good move for ambulatory patients on T3s?
starting senna blindly
What are the laxatives recommended for opiate-induced constipation?
osmotic laxatives (lactulose, PEG 3350)
stimulants
What are some drugs that can induce constipation?
opioids
first gen antihistamine
TCA
