Laxatives Lecture PDF Flashcards
If colon fluid reabsorption is excessive, stool consistency will be ___, if insufficient, then ___
dehydrated and harder to pass (constipation), watery diarrhea
Best source of fiber
Bran (about 40% fiber raw)
Constipation 1 criteria that must exist to diagnose
feces being hard and dry (regardless of how often they are passed)
Indications for laxative use (4)
- reduce painful elminiation associated with episiotomy, hemorrhoids and other anorectal lesions
- patients with CV disease to prevent straining
- compensate for loss of tone in abdominal and perineal muscle in geriatric patients
- empty bowel prior to procedure or those on narcotics
Rapid acting laxatives definition and examples (2)
Act within 2-6 hours but impart watery consistency to stool, useful for diagnostic procedures or surgery
- saline laxatives
- polyethylene glycol
Bulk forming agents mech of action
Effects identical to dietary fiber, form stool 1-3 days after treatment initiated, swell in water and form gel softening fecal mass and increasing bulk
Bulk forming agents indications (3)
- temporary constipation
- IBS or diverticulosis
- symptomatic diarrhea relief
Bulk forming agents ADR’s (1)
-administration with full glass of water to prevent esophageal obstruction
Bulk forming agents examples (3)
- psyllium
- methylcellulose
- polycarbophil
Surfactants mech of action
Produce soft stool after several days of treatment, alter consistency by lowering surface tension facilitating passage of water into feces
Surfactant examples (1)
-docusate sodium/potassium/calcium
Stimulant (irritant) laxatives mech of action
ACt on intestinal wall to produce net increase in amount of fluid and electrolytes within the intestinal lumen, promote accumulation by increasing secretion of water and ions into intestine and reducing water and electrolytes absorption, most act on colon within 6-12 hours
Bisacodyl (dulcolax) drug class and function
Stimulant laxative, indicated for intermittent use to treat constipation or as bowel prep
Senokot (x lax) drug class, mech of action, and ADR (1)
Anthraquinone derivative, thought to stimulate aurbach’s plexus, changes urine color
Castor oil
Only stimulant laxative that acts on the small intestine, metabolized in the GI tract to active compound, acts within 2-6 hours to produce stool of watery consistency but is too powerful for routine management of constipation
Osmotic laxatives mech of action
Poorly absorbed salts draw water into intestinal lumen increasing fecal mass stretching intestinal wall stimulating peristalsis
Osmotic laxatives function, ADRs (3)
low dose produce semisoft stool in 6-12 hours, high dose in 2-6 hours for bowel prep
-Dehydration, renal dysfunction, heart failure
Polyethylene glycol (miralax) function and ADR’s (3)
Osmotic laxative relatively safe for occasional constipation,
- N/V
- bloating
- flatulence
Mineral oil drug class and function
Lubricant laxative given orally or rectally posesses greater potential adverse effects than docusate and thus routine use should be discouraged
Laculose and sorbitol function
Saccharides used orally or rectally as having an osmotic effect allowing fluid to retain in colon, resulting in soft stool in 1-3 days, reserved as second line for patients who do not respond to bulk forming laxatives, can enhance intestinal excretion of ammonia (useful for portal hypertension)
Immunomodulators for inflammatory bowel dz
2nd line agents being used earlier in treatment to induce remission and maintain
TNF inhibitors 3 examples and funcion
-infliximab (remicade)
-adalimumab(humira)
certolizumab (cimizia)
Treatment for moderate to severe ulcerative colitis and crohns and RA
TNF inhibitors ADR’s (2)
- increased risk of serious infection
- reactivation and dissemniation of Tb
Tofacitinib (xeljanz) drug class and function and ADR’s (2)
Synthetic PO inhibitor of janus kinase, 1st PO agent approved for moderate to severe ulcerative colitis treatment
-TB and other opportunistic infections, bone marrow suppression
dicyclomine drug class and function, ADR’s (3)
anti-spasmodic used to treat irritable bowel syndrome, dry mouth, urinary retention, blurry vision
What antibiotic is preferred for travelers diarrhea in pregnant women?
Azithromycin
Natalizumab (tysabri) function and ADR
Maintenance of moderate to sever crohn’s, ADR is progressive multifocal leukoencephalopathy (PML)