colonic motility

or anorectal function

6 weeks

(may respond to laxatives but returns when laxatives are removed)

*Does not respond to dietary changes alone*

Common causes of Constipation

• dietary (poor fluid intake, ↓caloric intake)
• failure to heed defecation reflex
• impaired physical mobility
• lack of privacy
• psychological distress
• disease that slows GI motility
• drugs

• Opiods
• Antacids
• Anti-cholinergics
• Antidepressants
• Antihypertensives (verapamil, clonidine)
• Iron
• Diuretics
• Chronic use of stimulant laxatives (only in those who have GI motility)
  

• sx for >2 weeks
• black/tarry stools
• abdominal pain/discomfort
• fever
• N/V
• FH of inflamm bowel disease (crohn's) or colon cancer
• drastic change in severity/nature of sx

Length of constipation

Frequency of normal bowel movements

Size and Color of stools

Constipation with bouts of diarrhea?

Change in caliber of stools

Gas

Appetite/Weight change

Transit time in the GI

harder feces indicating slower transit

• include ample fluids and fiber in diet
• add high-fiber foods to diet slowly
• do not ignore the urge to have a bowel movement
• establish a regular, unhurried time for BM
• encourage defecation first thing in AM or w/in 30 minutes after meals
• routine physical activity
  

20-30g/day

Dried Plums

(affectionately known as Prunes)

• contain high conc of simple sugars (sorbitol)
• 1 cup = 12g of fiber
• dihydrophenylsatin (natural laxative)

*Good for adding fiber to diet*

magnesium citrate

sodium phosphate

Large doses of PEG

enemas

bisacodyl/glycerin suppositories

Milk of Mag

standard doses of PEG (Miralax)

bisacodyl/senna tablets (oral)

1. dietary interventions (failed prior)
2. bulk forming laxatives + adequate fluid intake
3. sorbitol/lactulose/PEG
4. stimulant laxative (short term)
5. lubiprostone (Amitiza)(Rx only)

routine use of stimulant laxative (suppositories)

attempt to "train bowel" (bowel program)

diet, fiber, docusate

senna in more severe cases

glycerin

Karo syrup (infants)

metoclopramide (↑GI motility)

stimulant laxative

Stimulant laxative

Then add lactulose, sorbitol, or PEG PRN

AVOID Bulk laxatives (bc no GI motility, will only lead to increased probs due to inability to move feces out)

Methylnaltrexone (Relistor) mu opiod receptor antagonist

8-12mg SC every other day

BM w/in 30 min

hyperosmotics/saline laxatives

clear liquid diet beginning day prior

prep with laxative starts afternoon before

large quantities of fluids

heart failure

renal disease

electrolyte abnormalities

*use in these patients is why these agents are Rx only

+ soften stools better than docusate

+ well tolerated with few SE

- taste

-must have adequate fluid intake

- gas formation (only with metamucil)

- impacts drug absorb

- not good for bedridden patients (bc have poor GI motility)

- Not for patients on chronic opiods

Metamucil (psyllium)

Citrucel (methylcellulose)

Fiber tabs

aka stool softeners

Docusate (100mg QD or BID)

decrease fecal surface tension

stool softener

+ safe

+ helps prevent hard stools (hemorrhoids)

- efficacy is questionable

- Not Effective for Active Constipation

lubricate lumen of colon

Mineral Oil (30-60mL QD)

- poor patient acceptance (oily and can be leaky)

- may ↓ absorption of fat-soluble vitamins (A,D,E,&K)

MOA: draw fluid into colon which stimulates motility

milk of mag

Mg Citrate

Phospha-soda

Fleet's Saline Enema

+ quick onset

+ most economical

- avoid in renal patients bc have a hard time excreting Na and Mg

Sorbitol (30-60mL QD)

Lactulose (30-60mL QD)

PEG (17g in water QD)

PEG = Miralax

+ well tolerated

+ softens while stimulating bowel movement

+ excellent for Chronic constipation

- 1-4 DAY onset

- sweet taste of some

- minor nausea, cramping

glycerin

fast onset

polythylene glycol

(Nulytely, Golytely, HalfLytely)

hyperosmotic agent

used as bowel prep (4L)

8oz Q 10 minutes

hyperosmotic agent

sometimes used in kids

1 tsp in 6-8 oz formula

Senna (2T QD to BID)

Bisacodyl (enteric coated) (1-2T QD)

Castor Oil (30-60mL)

Bisacodyl suppositories (10mg PR)

quick onset

+ 6-12 H onset

+ works for patients with mobility issues

+ DOC for patients on opiods

- risk of cramping

- avoid long-term use in patients with GI motility

Lubiprostone (Amitiza)

24mcg BID with food

8mcg BID for women with IBS

increase influx of fluid into small intestine

diarrhea/nausea/HA

Expensive

Avoid in pregnancy

1-2 days for acute

1-2 weeks for chronic constipation

look for:

stool frequency, diarrhea episodes, dietary changes