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)