Constipation Assessment and OTC Pdts Flashcards
constipation is more commo in ?
Constipation is a symptom.
◦ Establishing the cause is important in correcting.
More common in the elderly – incidence 40% or higher.
Incidence female>male (2.5 fold)
Many patients will self-treat.
Definition of constipation
Definition: ”unsatisfactory defecation – infrequent stools, difficulty passing stools or both”
Infrequent bowel movements
◦ Often use stool frequency of less than 3 stools per week.
Difficulty in passing stools, often with straining
Stool consistency – hard/lumpy
Other symptoms: sensation of incomplete evacuation,
bloating, discomfort
Diagnostic Criteria for Chronic Constipation
ROME IV
Presence of > 2 of the following for last 3 months (onset at least 6 month before dx): Straining Lumpy/hard stools Sensation of incomplete evacuation Sensation of anorectal obstruction/blockage Manual help to facilitate defecation <3 spontaneous bowel movements per week Loose stools not present (could be IBS) NOT IBS symptoms
What is normal bm?
“Normal” frequency can vary from person to person
Having a BM everyday is not always “normal” for every
person.
Constipation is essentially change in bowel habits form what is normal for that person
causes of constipation
Primary constipation:
No identifiable underlying cause
3 types:
◦ Normal transit constipation: no changes in gi transit, most common
◦ Dys-synergic (disordered) defecation: 25%, inability to coordinate muscles involved
◦ Slow transit constipation: slow down GI tract
Causes of constipation
Secondary constipation:
Identifiable underlying cause: ◦ Lifestyle factors ◦ Medical conditions ◦ Medications See Table 1 of handout
What drugs cause constipation?
Calcium supplements, antacids, iron supplements, antihistamines, antidiarrheal agents, dimenhydrinate
Rx: opiods, anticholinergics, ccb, TCA, antidepressent
diuretics, antispasmodics, antipsychotics, antiepileptics
Complications of constipation
Hemorrhoids Fissures Fecal impaction Megacolon Straining—negative effects on cerebral, coronary and peripheral arteries Malnutrition Rare: pelvic organ prolapse in women, very rare - intestinal perforation
Patient Assessment
1) Identify the predominant symptoms.
what q;s would you ask?
◦ Clarify patients definition of constipation.
◦ Determine normal bowel habits.
◦ Frequency/last bowel movement
◦ Duration - distinguish acute vs chronic
Onset abrupt or gradual?
What do you mean by constipation?
What is your normal bowel patterns?
If you pass any stools, can you describe its
consistency and colour? (bristol stool chart)
Type 6-7 diarrhea
Type 4 is ideal
Patient Assessment
◦ Patients description of severity
• mild severe
◦ Other accompanying symptoms:
abdominal pain, bloating, sensation
of incomplete evacuation, straining,
nausea/vomiting, reduced appetite,
weight loss, rectal bleeding
Do you experience any other symptoms?
Patient Assessment
2. Identify possible secondary
causes or aggravating factors
◦ Medical conditions
◦ Identifiable drug causes check for Rx, OTC and natural health products, new additions or changes
◦ Non-drug/lifestyle causes Describe diet/fluid intake
What makes your constipation worse?
Are there any triggers?
Patient Assessment:
3. Assess for “red flags” that require further
assessment
Blood or mucus in stool or rectal bleeding Unexplained iron deficiency anemia Unexplained weight loss >5% Persistent or severe abdominal pain Palpable abdominal mass Fluctuates with diarrhea Sudden acute/severe onset Symptom onset >50 years of age Family history of colon cancer
Patient Assessment
4. Assess what has been tried to help with constipation
(lifestyle, laxatives, etc)?
◦ For how long?
◦ What doses?
◦ How did it work?
◦ Were there any side effects?
Treatment approaches: Non-pharmacologic
diet
how much fiber?
fluid intake?
Diet
High fiber diet:
◦ Target 28 – 38 gm per day
◦ Increase fiber gradually to avoid bloating, cramping
Fluid intake (i.e. 2 - 3 L per day) to complement
increased fiber
Fruit in diet
Prune juice or figs (contain sorbitol – highest
amounts in prunes, also in pears, apples)
Sorbitol is a laxative in fruits
Fibre in the skin
Eating apple with skiin
Treatment approaches: Non-pharmacologic
Lifestyle
Regular exercise
Regular bowel movement
Avoid suppressing urge to defecate
If obese – weight loss will help
If low calorie diet – increase calories
Consider alternative drug if using constipating drug
(if possible)
If underlying medical cause – attempts to correct it
(for example hypothyroidism)
Biofeedback and relaxation training if chronic
constipation
Insoluble: wheat bran, fruits Soluble: beans, lentils Can consder combination Be cautious in pt with IBS Insoluble can cause bloating and abdominal pain
Four general classes of laxatives sold as OTC:
◦ Bulk forming laxatives ◦ Osmotic laxatives ◦ Stimulant laxatives ◦ Emollient/stool softener Prescription medications available. Usually follow a step-wise approach May have different approaches for different causes
Bulk Forming Laxatives
which are solube fibers?
which are synthetic and which are natural
Bran – soluble/insoluble fibers
Soluble fiber:
Psyllium (e.g. Metamucil®, generics) – natural fiber from husks of plant seeds, another name is ispaghula
Calcium polycarbophil (e.g. Fibercon etc) synthetic Methylcellulose (e.g. Citrucel®) – synthesized from plant cellulose
Others: all natural
◦ inulin (soluble fiber from chicory root)
◦ guar gum (e.g. Benefiber®)
◦ sterculia gum (e.g. Normacol®)
Bulk forming laxatives
AE
onset
Onset: 12 – 72 hours
Must be taken with adequate water (250 ml water)
Often first line of treatment except constipation from
poor GI motility or opioids.
Avoid: dehydrated or fluid restricted
Adverse effects: bloating, flatulence, diarrhea
Diarrhea is not a big concern unlike other laxatives
Soluble fiber -fermented by bacteria and causes an increase in short chain fatty acids
Bulk forming laxatives
how do they work
what is required
which type has more flatulence?
Retain water in stools
Causes normal GI motility
Qorks with bodys own system
Results in increased GI motility
Need water
Not first line if pt is not hydrated
Or if pt is on opiates as it affects GI motility, reduces motility
Good for mild or ongoing pt
Natural soluble fiber (esp psyllium) more flatulence
compared to synthetic fibers or methylcellulose
Drug interactions: avoid use within 2 hours of
administration
Osmotic laxatives
how do they work
types (2)
Poorly absorbed solutes or ions act by exerting an
osmotic gradient and retain water in the lumen.
Solutes or ions pooly absorbed in GI tract
Brings out water which stimulates the tract
Types of Osmotic Laxatives:
◦ Saline Laxatives
◦ Hyperosmotic
Osmotic laxatives: Saline
types (3)
onset
Poorly absorbed ions Quick onset – 0.5 – 3 hours Types: ◦ Mg hydroxide (Milk of Magnesia®, generics) ◦ Mg citrate (Citro-Mag®, generics) ◦ Sodium phosphate (e.g. Fleet® enema)
Mag for acute or chronic cnst
But needs to have normal renal; function
Osmotic laxatives: Saline
when s it used?
caution with which electrolyte abnormalities
Used for complete bowel evacuation.
Mg hydroxide/citrate can be considered for
acute/chronic constipation as long as normal renal
function.
Requires adequate fluid intake
electrolyte abnormalities (éMg, phosphate, low
calcium, low Na, low K), diarrhea and dehydration
Avoid if renal impairment or heart diseas
Osmotic laxatives: Hyperosmotic
types (name 3)
Glycerin suppositories
Polyethylene Glycol (PEG)-3350
Lactulose
Osmotic laxatives: Hyperosmotic
Glycerin suppositories
how it works
onset
AE
Retains fluid in rectum
Carbohydrate that causes GI contractions
Retians fluis in rectum
Very quick
Onset – quick, 15 – 30 minutes
Adverse effects: well tolerated but can cause local irritant effect
Not as good if you have very hard stools, better if you have some bowel movement
Useful for children
Instructions: moisten with lukewarm water then insert
and retain as long as possible (ie 15 – 30 minutes).
Osmotic laxatives: Hyperosmotic Polyethylene Glycol (PEG)-3350
how it works
onset
AE
Polymers of ethylene glycol – binds to water molecules
◦ Not absorbed or metabolized by bacteria
Used a lot for chronic constipation
Good for elderly pt with littlee side effects and contraind
Onset: 48 – 96 hours
Adverse effects: bloating, flatulence (less compared to
other osmotic agents), diarrhea, high doses – electrolyte disturbances
Not as much flatulence cuz not met by bacteria
Drug interactions: avoid use within 2 hours of
administration
Osmotic laxatives: Hyperosmotic
PEG products for acutie/ chronic cons vs complete bowel evaculation
Acute or chronic constipation
I.e. Restoralax®, Lax-A-Day®, Pegalax®
Complete bowel evacuation (before surgery or
diagnostic procedures or for refractory constipation)
◦ Large volume (ie 2 L)
◦ I.e. Golytely® with electrolytes
Osmotic laxatives: Hyperosmotic Lactulose how it works onset AE
Lactulose Non-absorbable disaccharide (fructose, galactose) Disaccgride joined together Can be absorbed when broken down By bacteria
◦ Metabolized by bacteria in colon to low MW fatty
acids that cause osmotic effect
Onset: 24 – 48 hours
Use: acute or chronic constipation
Adverse effects: flatulence, bloating, nausea,
diarrhea (more flatulence due to bac)
Osmotic laxatives: Hyperosmotic
Lactulose
may decrease ________ absorption
Sweet taste – can be masked by diluting in water,
juice, or milk
Drug interactions: avoid use within 2 hours of
administration.
May decrease vitamin K absorption (increase
INR) – interaction with warfarin “moderate”.
Monitor INR
Sorbitol is a cheaper alternative.
Stimulant laxatives
3 tytpes
onset
when is it used?
Stimulant laxatives:
◦ Anthranoid laxatives – plant derived sennosides (ie Senokot®, Ex-Lax®, generics) cascara
onset: 8 – 10 h
◦ Bisacodyl (Dulcolax®, generics): - synthetic oral – 6 – 8 h, supp – 0.5 – 1 h large interpatient variability with dose
◦ Sodium picosulfate (Dulcolax Pico®)
Use: 2nd line to osmotic laxatives for acute constipation, may be used for opioid induced constipation
Not recommended for regular use without chronic constipation
Stimulate myenteric plexus, neurons that supply GI tract and cause GI motility to happen
Stimulant laxatives
AE
concerns about long term use
Adverse effects: abdominal cramps, hypokalemia, diarrhea, supp – irritation
Senna discolors urine/feces, goes into breast milk
Cramping–> more issues in elderly patients
Diarrhea is greater riskvery old or young
Concerns about long term use:
◦ Rectal atomy (cathartic colon) – little evidence (however, tolerance may develop BUT rare)
Rectal atomy: slowing down of tract, becomes lazy, needs stimulant to work
Little evidence that it happens, but you can see some tolerance
◦ Excessive use of anthranoids – melanosis coli
Melanosis coli: anthranoid laxatives, senna, melatonin, hyperpigmantation
Can be reversed, not life threatening, benign
Bisacodyl oral are enteric coated – caution with use of PPI or H2blockers
Emollient/stool softeners
how it works
onset
pdt names
Mix with fatty materials, aquesous materials to soften the stool
Docusate sodium, docusate calcium
◦ Colace®, generics
Onset: 12 – 72 hours
Have been found to be ineffective for constipation and
are no longer recommended.
Note: Mineral oil, also classified as an emollient, is not
recommended (can affect fat soluble vitamin absorption (A, D, E, K); cause
lipid aspiration)
Enemas
how it works
onset
Administering Enema
Lubricate nozzle (if not lubricated)
Lie on left side with knees bent
Insert the nozzle in the rectum, with pointing
towards navel
Gently squeeze the container, if discomfort than
it is too fast
Retain the solution until cramping is felt.
Stretches colon to produce urge to defecate Faster onset – within one hour Examples: ◦ Mineral oil retention enemas ◦ Phosphate enemas ◦ Tap water enemas Use: acute or chronic constipation
