constipation

Question 1

constipation definition

Answer 1

decreased frequency plus:

cramping, bloating, lumpy/hard/dry stools, straining, sensation of incomplete evacuation

Question 2

constipation etiology

Answer 2

over 4 million in US are frequently constipated
more common is: women, non-white, elderly
*most patients treat themselves
$500-800 mil./year
30-50% of elderly frequently use laxative (higher in LTCF)
disorder of colonic motility or anorectal function

Question 3

acute constipation

Answer 3

less than 3 bowel movements/week

usually brought on by change in condition or drug

Question 4

chronic constipation

Answer 4

symptoms lasting more than 6 weeks
may respond to laxative, but sxs return when d/c
does not respond to dietary changes alone
chronic idiopathic

Question 5

common causes of constipation

Answer 5

elderly
dietary - poor fluid intake, decreased caloric intake
failure to heed defecation reflex
impaired physical mobility
lack of privacy (LTCF)
increased psychological distress
disease states that slow down GI motility* - DM, parkinsons, CNS and spinal cord injury or disease
drugs

Question 6

drugs that cause constipation

Answer 6

analgesics* - opioids (PO more than IV, can occur w/in 3 hours, mu receptor in GI tract) NSAIDs to a lesser extent (inhibition of PGs)
antacids (Al, Ca)
strong ACh properties (AHs, antimuscarinics, amitriptyline)
verapamil, clonidine, CCBs
iron
diuretics (remove fluid from system)

Question 7

when to refer

Answer 7

sxs have persisted for greater than 2 weeks* w/o significant relief
black or tarry stools
marked abdominal pain or discomfort
fever
severe NV (obstruction)
FH of IBD or colon cancer
drastic change in severity or nature of symptoms

Question 8

nonpharm treatment

Answer 8

include ample fluids and fiber in diet (6-8 glasses of water/day)
add high-fiber foods to diet slowly - 20-30 g/day, increase over 7-10 days (minimizes gas b/c natural fiber is degraded by bacteria), vegetables, fruits, beans, whole grains
prunes (dried plums) - high conc of simple sugars (sorbitol), 1 cup = 12 g fiber, dihydrophenylsatin (natural laxative)
power pudding - 1/2 C prune juice, 1/2 C applesauce, 1/2 C wheat bran flakes, 1/2 C whipped topping, 1/2 C prunes - blend, cover, refrigerate, take 1/4 C daily w breakfast
do not ignore urge to go
establish a regular, unhurried time for BMs (first thing in AM, 30 min after meals)
morning coffee?? craft beer???
SF gummy bears - sorbitol
routine physical activity
lexatives are generally for occasional* use only

Question 9

bulk laxatives

Answer 9

psyllium (metamucil), methylcellulose (citrucel), calcium polycarophil (fibercon)
MOA: forms emollient gels which retain water, smells and stimulates BM, tension on GI wall creates peristalsis
advantages: softens stool beter than docusate, well tolerated, few SE
disadvantages: taste, must have adequate fluid intake, gas formation, impact on drug absorption*, not ideal for bed ridden patients
methylcellulose considerations: must mix with cold water, produces less gas

Question 10

surfactant/emollient

Answer 10

docusate 100 mg QD or BID
MOA: decreases fecal surface tension, stool softener
advantages: safe, helps prevent hard stools
disadvantages: efficacy??, not effective for active constipation**

Question 11

lubricant

Answer 11

mineral oil 30-60 ml QD
MOA: lubricates lumen of colon, “slide on through”
advantages: lubricates, softens
disadvantages: poor patient acceptance, oily, may decrease absorption of fat soluble vitamins
“magic mousse”

Question 12

saline laxatives

Answer 12

MOM, Mg citrate
MOA: draws fluid into colon which stimulates motility
advantages: used for acute management of constipation, quick onset, most economical
disadvantages: taste +/-, avoid in renal patients (Na, Mg)***
fleets saline enema - rapid onset

Question 13

hyperosmotic agents

Answer 13

sorbitol 30-60 ml QD, lactulose 30-60 ml QD, PEG 17 g in 4-8 oz H2O QD
MOA: draws fluid into colon due to high conc of sugar, PEG, or glycerin
advantages: well tolerates, softens while stimulating BM, excellent for chronic constipation
disadvantages: 1-3 day onset, sweet taste (lactulose), minor nausea, cramping
glycerin suppositories - child or adult, quick onset
karo corn syrup - used in children, 1 tsp in 6-8 oz formula

Question 14

stimulant laxatives

Answer 14

senna 2 tabs 1-2x/day, bisacodyl 1-2 tabs QD, castor oil 30-60 ml
MOA: locally irritates nerves which stimulate mobility
advantages: 6-12 hours to onset, works in patients w motility disorders, DOC for patients on opioids**
disadvantages: cramping, avoid long-term use in patients with normal GI motility
bisacodyl suppository 10 mg PR, quick onset

Question 15

chloride channel activator

Answer 15

lubiprostone (Amitiza)
activates chloride channels in small intestive resulting in increased intestinal fluid
chronic idiopathic constipation in adults
24 mcg BID with food*
diarrhea/nausea/HA
expensive
avoid in pregnancy*
reserved for patients who don’t tolerate other laxatives

Question 16

guanylate cyclase-C receptor activator

Answer 16

linaclotide (Linzess)
increases chloride and bicarbonate secretions into the intestinal lumen; also inhibits sodium absorption
chronic idiopathic constipation in adults
145 mg QD 30 min before 1st meal of the day
expensive

Question 17

treating acute constipation for patients seeking rapid symptomatic relief

Answer 17

0.5-3 hours: magnesium citrate, larger doses of PEG
0.5-1 hours: enemas (fleets, tap water, soap), suppositories (bisacodyl, glycerin)
6-24 hours: MOM, standard doses of PEG, bisacodyl, senna

Question 18

follow up and assessment

Answer 18

1-2 days for acute constipation
1-2 weeks for chronic constipation
stool frequency, episodes of diarrhea, dietary changes, any SEs

Question 19

step wise treatment of chronic constipation

Answer 19

1: be sure dietary interventions have been attempted (“power pudding”)
2: bulk forming laxative + adequate fluid intake
3: sorbitol/lactulose/PEG
4: short term stimulant laxative
5: lubiprostone, linaclotide

Question 20

treatment of special populations w constipation

Answer 20

spinal cord injury: routine use of bowel stimulants (usually suppositories)
pregnant: diet, fiber, docusate, senna in severe cases
children: glycerin supp, karo syrup
diabetics: metoclopramide, stimulants
opioids: stimulants, then + docusate, lactulose, sorbitol or PEG PRN, avoid bulk laxatives*, “push not gush”
post op: start with MOM or PEG, then stimulants, push fluids

Question 21

methylnaltrexone

Answer 21

useful for patients on opioids
use when other treatment doesn't work
dosed based on weight
8-12 mg SQ QOD
expect BM within 30 min
\$\$$

Question 22

naloxegol

Answer 22

useful for patients on opioids
mu opioid receptor antagonist
25 mg PO QD
\$\$$
can be crushed
take 1 hours before 1st meal or 2 hours after (empty stomach**)

Question 23

alvimopan

Answer 23

indicated for tx of post-op ileus
12 mg PO 30 min before surgery
12 mg PO BID starting day after surgery
max of 15 doses
restricted access program
\$\$$

Question 24

preps for GI procedures

Answer 24

hyperosmotics or saline laxatives, clear liquid diet starts day prior to procedure, prep starts in afternoon prior to procedure
PEG - 2-4 L, 8 oz q 10 min, refrigerate, taste??? cyrstal light
osmoprep, visicol - Na phosphate, $$$
suprep - NaSO4, KSO4, MgSO4
suclear - NA sulfate, K sulfate, Mg sulfate, PEG 3350
prepopik - Na picosulfate, Mg hydroxide, anhyrous citric acid, lowest volume prep - 10 oz
avoid previous 4 with HF, renal disease, electrolyte abnormalities