Define constipation
infrequent bowel movements (less than 3 per week) or difficulty in passing stools (straining, lumpy/hard stools, pushing for more than 10 mins, digital evacuation)
When constipation persists for several weeks or longer, and the cause is unknown, it is termed
chronic idiopathic constipation (CIC)
Idiopathic constipation is associated with chronic or recurrent
abdominal discomfort that is relieved by defecation is termed irritable bowel syndrome with constipation (IBS-C)
Medical conditions that can cause constipation
IBS-C, anal disorders (fissures), MS, cerebrovascular events, parkinson disease, spinal cord tumors, diabetes, hypothyroidism
Non-drug treatments for constipation
increasing fluid intake, limiting caffeine and alcohol intake and increasing physical activity
First-line treatment for constipation and treatment of choice in pregnancy
bulk-forming drugs
MOA of bulk-forming drugs
they absorb water in the intestine which adds bulk to the stool. this increases peristalsis and decreases stool transit time
MOA of osmotics
they draw fluid into the bowel lumen through osmosis which distends the colon and increases peristalsis
MOA of stimulant laxatives
directly stimulate neurons in the colon, causing peristaltic activity
MOA of stool softeners
emollients that reduce surface tension of the stool oil-water interface, allowing more water and fat to mix with the stool
MOA of lubricants
they coat the bowel and stool with a waterproof film
What drugs are bulk-forming
psyllium, calcium polycarbophil, methylcellulose, wheat dextrin
Brand name of psyllium
Metamucil
Brand name of calcium polycarbophil
FiberCon
Brand name methylcellulose
Citrucel
Brand name of wheat dextrin
Benefiber
What drugs are osmotics
magnesium hydroxide, polyethylene glycol, glycerin, lactulose, sodium phosphates, sorbitol
onset of action for bulk-forming drugs
12-72 hours
Side effects of bulk-forming drugs
flatulence, abdominal cramping, bloating, bowel obstruction
onset of osmotics
30 mins to 96 hours (oral), 5-30 mins (rectal)
Side effects of osmotics
electrolyte imbalance, abdominal cramping, abdominal distention, dehydration
lactulose is commonly used for
hepatic encephalopathy
What drugs are stimulant laxatives
senna, bisacodyl
Brand name of senna + docusate
Senna S or Senokot S
Onset of action of stimulant laxatives
6-12 hours (oral), 15-60 mins (rectal)
What drugs are emollients
docusate sodium
Brand name of docusate
Colace
Onset of action for emollients
12-72 hours (oral), 2-15 mins (rectal)
docusate is preferred when
straining should be avoided (postpartum, post-MI, hemorroids)
What drugs are lubricants
mineral oil
onset of action for lubricants
6-8 hours (oral), 2-15 mins (rectal)
MOA of lubiprostone
acts on chloride channels in the gut leading to increased fluid and peristalsis
Brand name of lubiprostone
Amitiza
Indications for lubiprostone
CIC, OIC, IBS-C in adult women
MOA of linaclotide and plecanatide
guanylate cyclase C agonist- increase chloride and bicarbonate secretion into the lumen of intestine, increasing the speed of GI transit and reducing abdominal pain
Brand name of linaclotide
Linzess
Brand name of plecanatide
Trulance
Indications for Linzess and Trulance
CIC, IBS-C
Common side effect of Amitiza
Nausea
Common side effect of guanylate cyclase C agonist
Diarrhea
MOA of peripherally-acting mu-opioid receptor antagonists (PAMORAs)
act on mu-opioid receptors in the GI tract, decreasing constipation
What drugs are PAMORAs
alvimopan, methylnaltrexone, naloxegol, naldemedine
Brand name of alvimopan
Entereg
Brand name of methylnaltrexone
Relistor
Brand name of naloxegol
Movantik
Entereg is for
hospitalized surgery patients to decrease risk of postoperative ileus
What are the indications of Relistor, Movantik and Symproic
OIC
Brand name for naldemedine
Symproic
MOA of prucalopride
serotonin 5HT-4 receptor agonist- release ACh which causes muscle contractions and increases GI motility
Brand name of prucalopride
Motegrity
Which laxative used for whole bowel irrigation has a boxed warning for nephropathy
OsmoPrep
Generic name for OsmoPrep
sodium phosphates
Brand name for PEG electrolyte solution
Colyte, GoLytely
Brand name for sodium sulfate, potassium sulfate and magnesium sulfate
Suprep Bowel Prep Kit
Most common bacterial cause of diarrhea
E. Coli
Non-drug treatment management of diarrhea
fluid and electrolyte replacement
Patient with non-infectious diarrhea who require symptomatic relief can use short-term
bismuth subsalicylate or loperamide prn
MOA of antimotility drugs
slows intestinal motility, prolonging the time for water absorption
Which drugs are antimotility
loperamide and diphenoxylate
MOA of eluxadoline
mixed mu-opioid receptor agonist- binds to opioid receptors as an agonist to treat diarrhea
Brand name of eluxadoline
Viberzi (C-IV)
Side effects of bismuth subsalicylate
black tongue/stools, salicylate toxicity (tinnitus, metabolic acidosis), nausea, abdominal pain
What antidiarrheal can cause an increased risk of bleeding when used with anticoagulants and antiplatelets
bismuth subsalicylate
Brand name for loperamide
Imodium A-D
How to take loperamide
4 mg PO after the first dose, then 2 mg after each loose stool
(max 8 mg/day)
Brand name of diphenoxylate/atropine
Lomotil (C-V)
Brand name of dicyclomine
Bentyl
Contraindication for Viberzi
patients without a gallbladder
Which medications for diarrhea have anticholinergic effects
Lomotil and Bentyl
What drug is a serotonin 5HT-3 receptor antagonist and approved for women only but has restricted use due to the risk of ischemic colitis
Alosetron (Lotronex)