Constipation

Question 1

Definition

Answer 1

• Less than 3 BMs/week + straining/ difficult passage of hard, dry stools
• Patient descriptions:
• Straining to have a BM
• Hard, dry stools
• Small stools
• Feeling that BM is incomplete
• Decreased stool frequency

Question 2

Pharmacologic Causes

Answer 2

• Analgesics and opioids
• Antacids (calcium)
• Anticholinergics, anti-motility agents, antihistamines
• Diuretics, iron
• Serotonin agonists (ondansetron)

Question 3

Lifestyle Contributions

Answer 3

• Inadequate dietary fiber
• Sedentary lifestyle
• Insufficient fluids
• Ignoring the urge to defecate

Question 4

Signs & Symptoms

Answer 4

• Decreased frequency or difficulty passing stools
• Anorexia
• Dull headache
• Lassitude
• Low back pain
• Abdominal discomfort
• Bloating/distention
• Flatulence
• Psychosocial distress

Question 5

When to Refer to Provider

Answer 5

• Age <2 years old
• Severe symptoms (abdominal pain, significant cramping/distention, N/V, fever)
• Marked or unexplained flatulence
• Chronic condition (paraplegia/quadriplegia, [IBD], colostomy)
• Anorexia/weight loss
• Bloody or black/tarry stools
• Marked change in character of stool (e.g., becomes pencil thin)
• Duration of symptoms >2 weeks or recur over at least 3 months
• Symptoms that recur after dietary or lifestyle changes
• No improvement with self-treatment >7 days

Question 6

Non-pharmacologic Treatment

Answer 6

• Balanced diet with F/V/WG
• Daily fiber intake (14 g/1000 kcal), 25g/d W and 38g/d M
• Gradually increase insoluble fiber over 1-2 weeks; may take 3-5 days before effective
• If dietary modification is not effective, may use fiber supplement
- Inulin (FiberChoice®, Metamucil Clear & Natural®)
- Wheat dextrin (Benefiber®)
• Increase fluids to 2 L/day
- Pregnant (extra 300 mL) and lactating women (extra 750-100 mL)
• Bowel training
• Exercise

Question 7

OTC Pharmacologic Options

Answer 7

1. Bulk-forming agents
2. Hyperosmotics
3. Emollients
4. Lubricants
5. Saline
6. Stimulant agents

Question 8

Bulk Formers, Brands

Answer 8

• Methylcellulose (synthetic fiber) - Citrucel®
• Polycarbophil (synthetic fiber) - FiberCon®
• Psyllium (natural fiber) - Metamucil®, Konsyl®

Question 9

Bulk Formers: Indications

Answer 9

• Patients on low-fiber diets
• New mothers in the postpartum period
• Older adults
• Patients with colostomies, IBS, diverticular disease
• Prophylactically (surgery)

Question 10

Bulk Formers: MoA, Onset

Answer 10

• Swell in fluid of small/large intestines, form emollient gels (facilitate passage and stimulate peristalsis)
• Onset: 12-24 hrs, up to 72 hrs

Question 11

Bulk Formers: AEs, Counseling

Answer 11

• Abdominal cramping / flatulence / acute bronchospasm (if inhaled)
• Mix 1 tablespoon and drink with 8 oz of fluid/dose, separate by 2 hours of other medications

Question 12

Bulk Formers: Interactions, Warnings

Answer 12

(separate by 2 hours)
- All interfere w/ absorption of warfarin, digoxin, salicylates, Polycarbophil-oral tetracyclines and fluoroquinolones

• Avoid if swallowing difficulties, esophageal strictures, or on fluid-restricted diets
  • Hypercalcemia (calcium polycarbophil caplets and renal disease)
  • Dextrose content (concern w/ diabetes)

Question 13

Hyperosmotics: Brands, MoA

Answer 13

1. Polyethylene glycol (PEG) 3350 (MiraLAX®)
2. Glycerin (Fleet’s®)

MoA
• Large, poorly absorbed ions or molecules draw water into colon or rectum through osmosis to stimulate BM

Question 14

PEG 3350, MiraLAX: Info, AEs

Answer 14

• Short-term/occasional constipation (safe/efficacious)
• Used for bowel prep prior to colonoscopy
• Powder (17 g, 1 capful or 1 packet) daily PRN mixed in 4-8 oz of water
• Onset: 12-72 hrs, up to 96 hrs
• Caution in renal disease or IBS
• Available for self-care in age 17 and above

• Adverse effects: bloating, abdominal discomfort, cramping, flatulence, >34 g/day may lead to diarrhea and excessive stools

Question 15

Glycerin

Answer 15

• Rectal suppository for lower bowel evacuation
• Available in solid or liquid formulations
• Onset is quick! (15-30 minutes)
• Adverse effect: rectal irritation from overdosage

Question 16

Emollients (stool softeners): Brands, MoA, Onset

Answer 16

1. Docusate sodium (Colace®): capsule/liquid in varying strengths
2. Docusate calcium: capsule, 240 mg

MoA:

• Anionic surfactants in SI/LI that increase the wetting efficiency of intestinal fluid
• Facilitate mixture of aqueous and fatty substances to soften fecal mass

Onset: 12-72 hrs, 3-5 days

Question 17

Emollients: Info

Answer 17

• To prevent straining and painful defecation in patients with anorectal disorders or when straining should be avoided (recent abdominal or rectal surgery)
• Combine with a stimulant (senna or bisacodyl) as long-term treatment for opioid-induced constipation
• Increases systemic absorption of mineral oil
• Larger than recommended doses may cause weakness, sweating, muscle cramps, and irregular heartbeat
• Counseling: increase fluids to increase softening of stool

Question 18

Lubricants - Mineral oil (liquid petrolatum)

Answer 18

• Softens feces in colon by coating stool and preventing colonic absorption of fecal water
• Onset: 6-8 hrs (oral), 5-15 minutes (rectal)
• Adverse effects/concerns:
- Lipid pneumonia (aspiration into lungs after oral dose)
- Do not use in <6 years old, pregnancy, immobile or older adults, or those with difficulty swallowing
- Anal leakage and pruritus (high doses)
- Immune reaction if reaches lymph nodes (long-term use)
- Impairs absorption of fat-soluble vitamins

(USE DISCOURAGED! TOO MANY SAFETY CONCERNS)

Question 19

Saline Laxatives: Forms, MoA

Answer 19

• Dosage forms

• Liquid or solid for oral administration
• Liquid for rectal administration

• MoA
- Draw water into SI/LI (oral products) or colon (rectal products) by osmosis, increase intraluminal pressure, and promote GI motility

Question 20

Saline Laxatives: Onset, Brands

Answer 20

• Mg OH: Milk of Magnesia, 30min-6hrs (oral)
• Mg citrate: Mg Citrate oral solution, 30min-3hrs (oral) and 2-15min (rectal)
• NaPhos: “Enema” products, 30min-3hrs (oral), 2-15min (rectal)
• MgSulf: Epsom salts: AVOID!

Question 21

Saline Laxatives: AEs, ed.

Answer 21

• AEs: abdominals cramping, N/V, dehydration
• NO if cannot tolerate fluid loss
• Oral doses of Mg salts -> 8 oz of water after
• Use at bedtime for occasional constipation

Question 22

Saline Laxative Concerns

Answer 22

RECOMMEND MAGNESIUM HYDROXIDE VS SODIUM PRODUCTS

Question 23

Stimulants: Brands, MoA

Answer 23

1. Senna (Senokot®)
2. Bisacodyl (Dulcolax®, Correctol®) - preferred stimulant

• 2nd line after bulk-formers or PEG 3350 for simple constipation
• MoA
• Increase intestinal motility by local mucosal irritation by acting on the intramural nerve plexus of intestinal smooth muscle
• Also increase secretion of water and electrolytes in the intestine

Question 24

Stimulants: Onset, AEs

Answer 24

• Onset: 6-10 hours after oral, up to 24 hrs. 15-60 minutes after rectal
• Adverse effects
• Severe cramping
• Electrolyte and fluid deficiencies
• Enteric loss of protein
• Malabsorption due to excessive hypermotility and catharsis
• Hypokalemia

• Senna may color urine pink-red, red-violet, or red-brown
- Do not crush or chew or take bisacodyl within 1 hr after taking antacid, H2RAs, PPIs, or milk

Question 25

Opioid-induced Constipation

Answer 25

• Chronic users should receive a long-term laxative to prevent and/or treat constipation • Stimulant laxatives (senna or bisacodyl, +/- docusate or PEG 3350) are most commonly recommended - Senokot-S® = senna 8.6 mg/docusate sodium 50 mg tablet

Question 26

Complementary Therapies

Answer 26

* Flaxseed - don’t recommend d/t limited efficacy and safety data * Aloe - unsafe and ineffective as laxative per FDA * Cascara - unsafe and ineffective as laxative per FDA * Probiotics - limited evidence

Question 27

To Pick a Med

Answer 27

• Consider what most mimics normal BMs - Bulk-formers closest but may take 72 hrs or longer - If faster onset is desired or bulk former is inappropriate/ineffective, PEG 3350 should be tried; consider stimulant if that doesn’t work - Use lowest dose and reduce once sx subside - Refer to provider after 7 days of non-rx if no benefit

Question 28

Children

Answer 28

- Most products not for < 6 y.o. w/o PCP advice - Mild constipation: diet (increase fluids, prune/apple juice) and behavior modification - Age 2-5: oral docusate sodium or magnesium hydroxide first, and senna; glycerin or sodium phosphate suppositories if ineffective - Age 6-12: methyl cellulose, calcium polycarbophil, docusate sodium, or magnesium hydroxide first, magnesium citrate, senna; glycerin, biscodyl, or sodium phosphate suppositories for quicker onset

Question 29

Elderly

Answer 29

- Review lifestyle modifications and medications first - Avoid bulk-formers if dehydrated, very frail, bedridden, or unable to drink fluids; avoid mineral oil and saline laxatives

Question 30

Pregnant/Brest-feeding

Answer 30

* Dietary measures first * Bulk formers or PEG 3350 first * Docusate if hard, dry stools * Short-term use of senna or bisacodyl also ok * AVOID castor oil, mineral oil, and saline laxatives * Senna, bisacodyl, PEG 3350, and docusate ok for breastfeeding (minimally absorbed or do not accumulate)