Week 5 - Constipation Flashcards
what is constipation
- defined as infrequent or hard to pass bowel movements
what is constipation a common cause of??
- painful defacation
what can severe constipation cause (2)?
- obstipation (failure to pass stools and gas)
- fecal impaction
what can obstipation & fecal impaction progress to? (2)
- bowel obstruction
- life-threatening
list 6 causes of constipation
- idiopathic primary or functional constipation
- diet
- meds
- metabolic & muscular
- structural & functional abnormalities
- psychological
what is idiopathic primary or functional constipation
- ongoing symptoms for greater than 6 months in the absence of other cause
what kind of diet promotes constipation (3)
- low fibre
- low liquid
- dieting (bc it lowers fecal bulk)
list a few examples of meds that cause constipation
joe said we dont have to memorize all these
- opioids
- diuretics
- antidepressants
- antihistamines
- anticonvulsants
- aluminum or calcium antacids
- calcium channel blockers
list a few examples of metabolic & muscular disorders that cause constipation
(once, again dont need to memorize all these but can if you want)
- hypercalcemia
- hypothyroidism
- DM
- celiac
- cystic fibrosis
- muscular dystrophy
list a few examples of structural & functional abnormalitirs that cause constipation
(same thing as others)
- spinal cord lesions
- parkinsons
- colon cancer
- anal fissures
- paralytic ileus
what is meant by psychological causes of constipation
- voluntary withholding of the stool
ex. fear of using public toilets
what is the type of drugs for constipation called?
laxatives
list 6 categories of antilaxatives
- bulk forming
- emollient (stool softener)
- hyperosmotics
- saline
- stimulants
- peripherally acting opioid antagonists
what are emollients?
- stool softeners & lubricants
what is the MOA of emollients (2)
- promote more water & fat in the stools
- lubricate the fecal material & intestinal walls
what is an example of stool softeners
- docusate salts (Colace)
what is an example of lubricants
- mineral oil
what are bulk forming agents?
- fiber based laxatives
what is the MOA of bulk forming agents (2)
- absorb water to increase bulk
- distend bowel to initiate reflex bowel activity
list 2 examples of bulk forming agents
- psyllium (Metamucil)
- methylcellulose (Citrucel)
what are hyperosmotics (osmotic agents)
- laxatives that work through osmosis
= draws water into the intestine & colon & increase fecal water content
what do hyperosmotics result in? (3)
- bowel distension
- increased peristalsis
- evacuation
what are 2 examples of hyperosmotics
- polyethylene glycol (PEG, lax-a-day)
- lactulose
what is another use of lactulose
- to reduce elevated serum ammonia levels
what are saline agents?
- agents that increase osmotic pressure within the intestinal tract = more water enters the intestines
what do saline agents result in? (3)
- bowel distension
- increased peristalsis
- evacuation
what is an example of a saline agent
- magnesium hyroxide (milk of magnesia)
what is the MOA of stimulants
- increases peristalsis via intestinal nerve stimulation
what are 2 examples of stimulants
- senna (Senekot)
- bisacodyl (Dulcolax)
describe the use of peripherally acting opioid antagonists
- treatment of constipation related to opioid use and bowel resection therapy
what is the MOA of peripherally acting opioid antagonists (3)
- block entrance of opioid into the bowel
- but not from the brain or spinal cord
- allow bowel to function normally with continued opioid use
what is one important thing to remember with peripherally acting opioid antagonists
- strict regulations for use
what are 2 examples of peripherally acting opioids antagonists
- methylnaltrexone (relistor)
- naloxegol (movantik)
what are 2 side effects of all laxatives
- diarrhea
- electrolyte imbalances (K, bicarb)
