Ch. 15 - Constipation

Question 1

Constipation

Answer 1

• Common GI complain
• <3 bowel movements/week that are strained and result in difficult passage of hard, dry stools
• Results from slow movement of feces in colon which results in accumulation in descending colon
• Elderly 5x more likely, women 3 x more likely than men

Question 2

Constipation described as… (5)

Answer 2

1. Straining for bowel movements
2. Passing hard, dry stools
3. Passing small stools
4. Feeling as though bowel movements aren’t complete
5. Reduced stool frequency

Question 3

Constipation Pathophysiology

Answer 3

• Food normally in stomach and small intestine for 3 hours each
• Ingestible matter absorbed and indigestible into large intestine and stored in sigmoid colon until defecation
• Peristaltic movement mores fecal matter into rectum and causes the desire to poop, relaxation of internal sphincter and tightening of abdominal wall muscles which causes a Valsalva maneuver forces poop down
• Defecation is this voluntarily inhibited or facilitated
• Primary or secondary in causation, primary is defecation disorders or slower-than-normal fecal movements
• Secondary causes: systemic, neurological, or psychological disorders or abnormalities that cause obstructions
• Dietary fiber dissolves or swells in intestinal fluids to increase fecal mass and peristaltic motions
• Diets low in calories, carbs, or fiber can lead to constipation
• Inadequate fluids and dehydration can cause constipation
• Exercise increases muscle tone and promotes bowel motility
• Resisting defecation urges can lead to constipation that may require retraining
• Medications can also cause constipation (Ex: opioids)

Question 4

Constipation Clinical Presentation

Answer 4

• Besides constipation, also anorexia, dull HA, lassitude, low back pain, abdominal discomfort, bloating, flatulence, and psychological distress
• Sporadic, temporary constipation okay to self-treat
• Constipation continuing over several weeks or months should be referred to PCP
• Complications can occur like hemorrhoids, fissures, anal bleeding, rectal prolapse, fecal impactations, ulcers, increase BP and cardiac disruptions

Question 5

Constipation Treatment Goals

Answer 5

1. Relieve constipation and reestablish normal bowel function
2. Establish dietary and exercise habits to prevent
3. Promote safe and effective use of laxatives

Question 6

Constipation General Treatment

Answer 6

• Adjust diet, increase fluid intake, exercise
• Pharmacologics should be used with these interventions together
• Don’t use pharmacologics for more than 7 days, if needed go to PCP
• Anal bleeding or persistent constipation after using laxatives - medical referral

Question 7

Constipation Exclusions

Answer 7

• Marked/severe abdominal pain
• Significant distension/cramping
• Marked/unexplained flatulence
• Fever
• N/V
• Sudden bowel habit changes
• Secondary constipation or constipation presenting with symptoms that may indicate secondary causes

Question 8

Constipation Nonpharmocologic

Answer 8

• Increase in fruit, vegetable, fiber, and whole grain intake
• 25 g of fiber for women, 38 g of fiber for men daily
• Limit intake of foods with little to no fiber (cheese, meals, processed foods)
• Can also supplement with fiber supplements like inulin, psyllium, and methylcellulose
• Benefits may take 3-5+ days
• Could initially cause erratic bowel habits, flatulence, and abdominal discomfort for 1st few weeks
• Slowly increase fiber intake over 1-2 weeks, also increase fluid intake to 2 L/day
• Encourage regular physical activity

Question 9

Constipation Pharmacologic

Answer 9

Ideal laxative:

1. Nonirritating and nontoxic
2. Only act on descending colon/sigmoid
3. Produces normal bowel movements in a few hours and then laxative stops action and normal function occurs
   - NO LAXATIVE HAS ALL THESE, choose based on patient need/etiology

Question 10

Bulk-Forming Agents

Answer 10

• Methylcellulose, polycarbophil, psyllium
• Swell/dissolve in small and large intestines to form emollient gels that increase peristalsis and fecal passage
• Many dosage forms available
• Onset: 12-24 hours, may be delayed up to 72 hours
• Provides short term relief for patients on low-fiber diets, postpartum women, older adults, patients with colostomies, IBS, or diverticulitis
• Don’t increase dose pass recommended, could cause obstruction
• Avoid in those who have difficulty, swallowing, restricted fluid intake, palliative care patients
• Avoid psyllium if you are allergic to it
• Many inhibit drug absorption by binding to medications
• Calcium polycarbophil decreases absorption of oral tetracyclines and quinolones by calcium chelation
• Separate bulk laxatives by 2 hours to other medications
• Don’t take if you have intestinal ulcers, stenosis, or disabling adhesion
• Potential SE: diarrhea, abdominal discomfort, flatulence, excessive fluid loss, abdominal cramping
• Access calcium intake in hypercalcemia risk patients, sugar content in diabetes, and aspartame intake in those with phenyketonuria

Question 11

Hyperosmotic Agents

Answer 11

• Polyethylene glycol 3350 and glycerin
• Contain large, poorly absorbed ions that draw water into colon or rectum via osmosis
• PEG 3350, good for 17 y.o.+, 17 g mixed in 4-8 oz of water
• Onset: 12-72 hours, delay up to 96 hours
• Only 0.2% systemically absorbed, quickly metabolized
• Safe and effective, few SE
• ASE: bloating, abdominal discomfort, cramping, has
• Caution use in diabetics and IBS
• No significant DD interactions
• Glycerin, suppository that works primarily in colon
• Onset: 15-30 minutes
• Safe for occasional use by all age groups
• Overdose: rectal irritation (don’t use enema version due to this) and decrease serum potassium concentrations
• Minimal SE and insignificant DD interactions

Question 12

Emollient Agents

Answer 12

• “Stool softeners,” anionic surfactants increase wetting efficiency of intestinal fluid to soften stool
• Primarily used to decrease straining and painful defecation in those with anorectal disorders
• Often combined with stimulant for long-term treatment of opioid-induced constipation
• Docusate onset: 12-72 hours, effective ~48 hours, sometimes medication requires 3-5 days
• Possible SE: diarrhea, mild abdominal cramping (well tolerated), weakness, sweating, muscle cramps, irregular heartbeat
• Don’t use in combination with mineral oil
• Not appreciably absorbed from GI and doesn’t hamper with nutrition absorption

Question 13

Lubricant Agent

Answer 13

• Mineral oil only non-Rx lubricant
• Coats fecal matter and prevents colon absorption of fecal
• Available as a liquid for oral or rectal administration
• Onset: 6-8 hours orally, 5-15 minutes rectally
• Prevent straining and painful defecation
• Not as safe as docusate
• Biggest safety concern: lipid pneumonia from aspiration into lungs after oral dose
• Caution use in young children (<6 y.o.), elderly, debilitated or bedridden, swallowing troubles, dysphagia, pregnant women
• Other ASE: anal pruritis, cryptitis, perianal conditions, foreign body reactions from reaching lymph nodes
• May impair fat soluble vitamin and medication absorption, don’t take with food

Question 14

Saline Laxative Agents

Answer 14

• Magnesium citrate, magnesium hydroxide, dibasic sodium phosphate, monobasic sodium phosphate, and magnesium sulfate
• Liquid or solid forms for oral or rectal use
• Ions retrained in small and large intestine and draw water in to increase intraluminal pressure and intestinal motility
• Use for occasional constipation relief or acute evacuation before a procedure

Question 15

Magnesium Hydroxide

Answer 15

• Magnesium hydroxide - good for occasional constipation in health patients; onset: 30 minutes - 6 hours
• Other preparations generally used for acute catharsis; onset: 30 minutes - 3 hours (oral), or 2-15 minutes (rectally), not recommended for OTC use since there are safer options
• ASE: cramping, N/V, or dehydration (drink with glass of water to decrease this SE)
• Can cause serious electrolyte imbalances after prolonged use or high doses
• Don’t recommend for electrolyte restricted diets
• Increased risk of magnesium toxicity in newborns, elderly, and renally impaired (avoid in these population)
• Magnesium preparations interact with tetracyclines
• Magnesium + Sodium Polystyrene Sulfate: systemic alkosis can occur

Question 16

Magnesium Toxicity Syndromes

Answer 16

• Hypotension
• Muscle weakness
• Fatigue

Question 17

Sodium Phosphate

Answer 17

• Should be used cautiously in renally impair, cardiac patients (CI: CHF), sodium restricted diets, diuretic or electrolyte altering drug users, megacolon, GI obstruction, imperforate anus, or colostomy
• Don’t use for bowel preparations, leads to renal impairment, not available OTC
• General DD Interactions: anticoagulants, digitalis glycosides, phenothiazines

Question 18

Stimulant Agents

Answer 18

• Anthraquinones (senna) or diphenylmathanes (bisacodyl)
• Don’t recommend unapproved supplements, NOT SAFE
• Work in colon to increase motility by causing local irritation to mucosa or selectively working on intramucal nerve plexus of intestinal small muscle
• Also increases water and electrolyte secretion in intestine
• Senna/Biscodyl onset: 6-10 hours, may take up to 12 hours (oral) or 15-60 minutes (rectal)
• Bis. often used as preparation for colonoscopies, also combined with docusate for opioid-constipation
• Overdose: sudden N/V, diarrhea, severe cramps (need medical attention
• Can cause electrolyte, water, and nutrition deficiencies
• Prolonged senna use can also cause reversible melanotic pigmentation of colonic mucosa (seen in scopies and biopsies
• Can turn urine pink, red, violet or brown
• Don’t take EC bisacodyl with antacid, H2RA, PPIs, or milk within 1 hour of administration

Question 19

Constipation Combination Products

Answer 19

• Often take advantage of different MOA
• Example: stimulant + emollient
• Can also combine things for immediate relief and then regularity promotion
• Example: Senna + Bulk-forming agent
• Increase potential for SE, especially when both act on one part of body

Question 20

Pharmacotherapeutic Compaison

Answer 20

• No good comparative evidence
• Recommend products with decrease likelihood of ASE
• PEG believed to have strongest support for efficacy safety
• Shown to be more effective than psyllium

Question 21

Product Selection Guideline

Answer 21

• Bulk-forming often initial choice so it can mimic natural physiological process
• PEG 3350 also considered first line for faster onset desires
• Stimulant should be considered in PEG isn’t giving satisfactory results, use lowest effective doses and decrease dose once symptoms improve
• No response after 7 days of treatment, medical referral

Question 22

Constipation - Children

Answer 22

• Delay in bowel movements 2 weeks+
• Unavailable toilet facilities, emotional distress, febrile illness, medical conditions, family conflict, dietary changes, fear of defecation, and changes to daily routine/environment can all increase constipation
• Identify causes/extraneous factors and decrease them
• Recommend dietary changes if impactation is suspected, medical referral
• Increase fluid intake with sorbitol there introduce high fiber foods into diet, fiber intake for 2 y.o.+ is their age + 5g per day
• < 2 y.o. needs medical referral
• Oral docusate, magnesium hydroxide, and glycerin are primary for children 2-6 y.o.
• Senna, sodium phosphate, and mineral oil are used second and used when the first line fails or under medical superversion
• 6-12 y.o. pretty much anything but PEG
• PEG 3350 approved for 17 y.o.+ but increasing use in kids
• 6-12 y.o. primarily use bulk-forming laxatives, docusate, or magnesium hydroxide; use stimulants if all else fail
• Use glycerin/bisacodyl suppository for fast relief
• Don’t recommend magnesium sulfate and castor oil - safer/better options

Question 23

Constipation - Elderly

Answer 23

• Greater risk due to dietary changes, decreased physical activity, comorbid conditions, increased medical use
• First, do a medication review to see if any medications are causing the constipation and if alternatives are available
• Recommend lifestyle changes (prune juice!)
• Assess for dehydration as possible cause
• If these fail, Bulk-forming laxatives - first line; don’t use in bedridden, dehydrated, frail, unable fluid intake
• PEG 3350 also first line for faster relief or if bulk-forming isn’t tolerated
• Stool softeners may be helpful with anal fissures or hemorrhoids
• Don’t use mineral oil and magnesium hydroxide
• Caution with saline and stimulant laxatives (fluid/electrolyte imbalance)
• Maybe avoid sodium phosphate due to phosphorous imbalances
• Discourage laxative overuse recommend by doctor

Question 24

Constipation - Preggo/BF

Answer 24

• Want soft stools without laxatives
• Primary: diet changes THEN laxatives if insufficient
• Bulk-forming is first line, docusate may also be good for dry, hard stools and is included in some prenatal vitamins
• Bisacodyl, senna, and PEG 3350 also acceptable choices especially for short-term use
• In severe cases, medical referral
• Avoid castor oil, mineral oil, long term saline laxative use
• Senna, bisacodyl, PEG 3350,and docusate are okay for breast feeding
• Don’t use castor or mineral oil while breast feeding

Question 25

Constipation Patient Factors

Answer 25

- Dosage forms and condition/diet restrictions need to be considered - Enemas routinely used for surgery prep, child birth, GI radiologic or endoscopic exams - Veggie oils lube, soften, and help pass hard stool - Tap water, saline, sodium phosphate bulk via osmotic effect (don't use sodium phosphate long term, significant fluid/electrolyte alterations) - Follow ALL directions when using enemas

Question 26

Constipation Patient Preferances

Answer 26

- Palatability and convenience are important - Mixing oral solution with water, milk, or juice can help - Warn against products labels grit, flavor, or taste free may be diet supplements instead - Cost also important, find a balance

Question 27

Constipation Complementary Therapies

Answer 27

- Common: flaxseed, aloe, cascara, and probiotics - Limited safety/efficacy for flaxseed, don't recommend - Choose FDA approved stimulant if indicated (Ex: aloe and cascara generally unsafe and uneffective) - Little evidence to support claims of probiotic efficacy, MAY benefit but considered investigational

Question 28

Constipation Assessment

Answer 28

- Get lifestyle and medication information before recommendation - Evaluate for signs of significant GI problems that may warrant medical referral - Ask about caliber, color, texture, and frequency of stools to understand level of severity - If cause can't be determined or questioning patient disease state then give them a medical referral

Question 29

Constipation Counseling

Answer 29

- Inform of nondrug measures first - Preggo and kids especially, recommend proper diet, fluid intake, exercise - Explain why a particular laxative is appropriate if use, how to use it, when you'll see results, possible ASE, and precautions to take

Question 30

Constipation Evaluation

Answer 30

- Consider type, severity, and chronicity of symptoms when determining appropriate treatments - Diet changes, exercise, bulk laxatives may take days to weeks to see effects - Hyperosmotic, saline, or stimulant laxatives: 3-72 hours for effects - Enemas: evacuation in minutes - Repeat therapy as needed per package directions - If relief isn't achieved within 7 days, medical referral - If laxative use for extended period of time is needed need a medical referral (can be a sign of severe constipation, medication side effects, or medical conditions) - High fiber diets and fluid intake should be maintained as consistently as possible regardless of pooping status