Constipation and Diarrhea Flashcards
Definition of constipation
Infrequent passage of stool or passage with difficulty
When is constipation more common?
Elderly
Women
Pts of low SES
Rome Criteria for constipation
Two or more of the following sx for at least 3 mos
- Hard stools at least 25% of the time
- Two or fewer BMs per week
- Difficulty passing (straining) at least 25% of the time
- Incomplete evacuation at a minimum of 25% of the time
What to ask the pt about constipation
Current bowel movements and consistency Usual bowel movements and consistency Associated sx Medical conditions Dietary habits Meds
Sx of constipation
Nausea -Can be present with or without vomiting Abdominal pain -Often described as "colicky" Urinary incontinence Diarrhea -Fecal matter higher in the colon is broken down and moves past the hard impacted fecal mass -Ask them when they had a meaningful BM
Alarming sx-constipation
Severe abd pain N/V Blood in stool A change in bowel habits >2 wks Worsening of constipation despite tx Tx >7 days unless directed by a PCP
Common reversible causes of constipation
Meds Reduced physical activity Reduced fluid intake -Dehydration Reduced food intake
Other common causes of constipation
Ileus Malignancy Autonomic dysfunction Mechanical obstruction Metabolic abnormalities Spinal cord compression
Meds that can cause c onstipation
Iron NSAIDs Opioids Diuretics Anticholinergics CCBs, esp. nondihydropyradine Calcium-containing antacids
Tx for constipation- goals
Prevention easier than tx
-Increase exercise, dietary intake fiber, fluid intake
Identify reversible causes and correct if possible
-Diet and meds commonly
Goal is two or three nl BMs per week with pt comfort being a goal as well.
Non-pharmacological tx options for constipation
Encourage fluids Activity as tolerated Encourage fiber in diet as tolerated -25-30 g per day -Whole veggies and fruit Avoid constipating meds if possible Provide a comfortable and private environment for defecation Educate about appropriate use of laxatives to minimize laxative abuse syndrome
Selection of tx for constipation
Minimal evidence to select one agent over another
Selection of a specific agent should depend on several factors such as cause, associated sx, medical hx, pt preference (administration), and cost
Laxative classifications
Lubricants Surfactants Prokinetic agents Osmotic laxatives Stimulant laxatives Bulk-forming agents Opioid receptor antagonists
Examples of bulk-forming agents
Psyllium
Methylcellulose
Polycarbophil
Advantages of bulk-forming agents
Natural
Cheaper
Well-tolerated
Onset of action of bulk-forming agents
12-72 hrs
More preventative than acute
SEs of bulk-forming agents
Bloating
Cramping
Flatulence
Clinical pearls of bulk-forming agents
Often considered first-line therapy
Requires adequate hydration, at least 8 oz of water per dose
Caution in debilitated pts
Example of chloride channel activator
Lubiprostone (Amitiza)
Use for chloride channel activator
Reserved for chronic idiopathic constipation: failed other therapies
More appropriate niche is IBS
Very expensive
What do the lubricants do for constipation?
Mineral oil inhibits water reabsorption in the colon
SEs of mineral oil
Depletion of fat-soluble vitamins
Clinical pearls of mineral oil
Reserved- last line
Oral formulation not recommended in debilitated pts- risk of aspiration
Examples of osmotic constipation meds
Lactulose or sorbitol
Polyethylene glycol- OTC
-Also comes in PEG-ES for bowel evacuation
Used more in hepatic encephalopathy (lactulose)
Use for osmotic constipation meds
2nd line
Onset of action of polyethylene glycol
24-96 hrs
Examples of osmotic/saline meds for constipation
Magnesium citrate or hydroxide
Use for magnesium citrate or hydroxide
Reserved- can cause electrolyte disturbances
Avoid in renal insufficiency and CHF
What are examples of opioid antagonists for constipation?
Methylnaltrexone
Alvimopan- hospital use only
Use of methylnaltrexone
For chronic opioid therapy
Does not cross blood-brain barrier, only acts on GI tract
Use of alvimopan
To prevent bowel obstruction after bowel resection surgery- reserved
What is an example of a prokinetic agent for constipation?
Metoclopramide
Use for metoclopramide
Reserved, think concomitant n/v
Often requires high doses
Examples of stimulants for constipation
Senna
Bisacodyl
Sodium phosphate
Onset of action for stimulants for constipation
6-12 hrs
SEs of stimulants for constipation
Nausea
Cramping
Electrolyte disturbance
Clinical pearls of stimulants for constipation
2nd or 3rd line
Possible dependence with long-term use
Sodium phosphate is last line agent
Use no longer than 7 days- exception might be opioid use
Senna and bisacodyl come in many different forms
What is a miscellaneous agent for constipation?
Linaclotide (Linzess)
Use of linaclotide
Chronic idiopathic constipation or IBS with constipation
What is an example of a surfactant for constipation?
Docusate sodium
Use of docusate sodium
Increases mixing of fatty materials in stool, 2nd or 3rd line
Requires adequate hydration
What is the indication for rectal drugs for constipation?
Institutionalized, one week of constipation, quick tx
Definition of diarrhea
Greater than or equal 3 unformed stools in 24 hrs
The passage of frequent, loose stools with urgency
Considered chronic if lasting longer than 30 days
4 broad categories of diarrhea
Secretory
Osmotic
Exudative
Altered intestinal transit
Common causes of diarrhea
AIDS Infection -Common in daycares and nursing homes Obstruction Meds Radiation therapy to bowel Malabsorption from cancers or resection
Meds associated with causing diarrhea
Abx Laxatives Cholinergics Mg antacids Chemo
Questions to ask for diarrhea
Diet -Changes in fiber, fat intake Appearance -Frequency, vol, consistency, and color Recent travel Med use Source of water Onset of sx and duration
Exclusions for self-tx of diarrhea
High-grade fever
Recent abx use
Severe abd pain
Pregnancy or child <6 mos
Pt is or is at risk for severe dehydration
Immunocompromised or severe chronic illness
If persists longer than 72 hrs or if gross blood or pus is present in stool
Tx principles of diarrhea
Dietary concerns Relieve sx Treat curable causes Treat any secondary d/os Prevent dehyrdation and electrolyte loss
Supportive care for diarrhea
Assess need for hydration and electrolytes
-Rarely needed in short-term
-Oral >IV
Clear liquids and simple carbs
Caution milk products to minimize risk of transient lactose intolerance
May d/c solid foods and dairy products x 24 hrs in adults
-Osmotic diarrhea
-Secretory: diarrhea persists
-Continue feeding children with acute bacterial diarrhea: BRAT diet: decreased morbidity and mortality
What are the general pharmacological classes for diarrhea?
Opioid agonists Anticholinergics Absorben (psyllium) Absorbent (attapulgite) Somatostatin analogues Mucosal prostaglandin inhibitors (bismuth subsalicylate)
What are the most effective oral agents for diarrhea?
Opioids
Loperamide facts
Often considered a drug of choice bc of efficacy, potency, and not crossing the blood brain barrier
Shown to inhibit peristalsis, prolong transit time, reduce fecal volume, and increase anal sphincter tone
Well tolerated with some peripheral opioid side effects
-Can still cause drowsiness
Loperamide dosing
4 mg PO initially, then 2 mg after each loose stool up to a max of 16 mg/day
Indications for loperamide
Traveler’s diarrhea
Nonspecific acute diarrhea
When pt has low grade fever no bloody stools
Codeine facts
DOES cross the blood brain barrier and can cause CNS depression
Effective but has many SEs
Other opioid antagonists are theoretically effective
Caution co-administration with other CNS depressants
Diphenoxylate with atropine facts
Prescription
DOES cross the blood brain barrier and can cause CNS depression
Little to no analgesic properties
Do not exceed 20 mg/day in adults
Combined with atropine to reduce abuse potential
MOA of anticholinergics for diarrhea
Work by decreasing secretions into the GI tract and possibly altering gut motility
SEs are numerous and efficacy is questionable
Do NOT recommend use for tx
Examples of anticholinergics for diarrhea
Atropine
Dicyclomine
Hyoscyamine
Lactobacillus preparations facts
Replace colonic microflora
Supposedly restores nl intestinal fxn and suppresses growth of pathogenic microorganisms
Use caution in IC pts
Wide range of cost
Lactase enzyme
For lactose intolerance
Directions specific to product selected
Monitoring for diarrhea
Viral infectious diarrhea is often self-limiting Monitoring should include: -Med adverse effects -S/sx of dehydration -Improvement in diarrhea within 48 hrs
