Therapeutics GI Petkewicz Flashcard

Etiologies of Chronic Neurogenic Diarrhea

  • Spinal Energy
  • Neuropathy (Diabetes)

Etiologies of Chronic Immunogenic Diarrhea

  • Crohn’s Disease
  • Ulcerative Colitis

Differences between Osmotic Diarrhea and Secretory Diarrhea

Osmotic Diarrhea

  • Poorly absorbed substances retain intestinal fluid — due to osmotic pressure
  • Malabsorption syndromes, lactose intolerance, Mg2+ containing antacids
  • Symptoms WILL subside as fasting occurs

Secretory Diarrhea

  • Stimulating substance decreases absorption of water and electrolytes and can cause increased secretion
  • VIP, unabsorbed dietary fat, hormones, bacterial toxins (cholera), excessive bile salts
  • Large stool volumes (> 1L/day)
  • Fasting DOES NOT change symptoms or stool volunes 

Exudative Diarrhea Etiologies

Inflammatory Bowel Disease

  • Crohn’s Disease
  • Ulcerative Colitis

-Stools may consist of only mucus, exudate, and blood

-Other issues including gut motility, secretory, and absorption properties affected due to large stool volume compensation

Antibiotics that lead to and treat Clostridium difficile Colitis

Causative Agents

  • Clindamycin (#1)
  • Fluoroquinolones
  • Cephalosporins
  • Penicillins

Therapeutic Agents

  • Vancomycin (PO)
  • Metronidazole (Flagyl)

Symptoms (Red Flags) of Diarrhea That Require Referral

  • Purulent, Bloody stools
  • Fever
  • Severe pain
  • Duration > 48-72 hrs with no improvement 
  • Marked dehydration (sunken eyes, skin turgor test, dry mucous membranes)
  • < 6 months of age, Elderly
  • Pregnancy

Oral Rehydration Solutions

  • Rehydrate Solution
  • Infalyte Solution
  • Resol Solution
  • Naturalyte Solution
  • Pedialyte Solution
  • Pedialyte Freezer Pops

Oral Rehydration Solution Indication
Preferred therapy for mild-moderate dehydration secondary to diarrhea, especially children
Oral Rehydration Solutions Clinical Pearls

Two Phases:

 

1. Rehydration — replace water/electrolyte deficits to restore normal body composition

2. Maintenance — maintain normal body composition

  • Premixed products preferred for safety/convenience
  • Content should not exceed 2:1 ratio of carbohydrate:Na+ to avoid carbohydrate induced osmotic diarrhea

 

 

Loperamide: MOA, Indications, ADE, CI

MOA

  • Peripheral μ receptor agonist
  • Slows intestinal motility and decreases secretion

Indications

  • Relief of non-specific acute diarrhea, traveler’s diarrhea (if patient is on antibiotic), or chronic diarrhea associated with IBD

ADE

  • Dizziness, constipation

CI

  • Avoid in patients with fecal leukocytes, high fever, blood/mucus in stool

 

Bismuth Subsalicylate: MOA, Indication, ADE, Rx-Rx, CI

MOA

  • Inhibits intestinal secretions and antimicrobial activity

Indication

  • Relief of mild nonspecific acute diarrhea, prevent traveler’s diarrhea

ADE

  • Salicylate toxicity (mild tinnitus)
  • Reye’s syndrome in children with viral illness
  • Black stools/darkening of tongue

Rx-Rx

  • warfarin
  • valproic acid
  • methotrexate
  • probenecid
  • tetracycline
  • quinolones, antibiotics

CI

  • Hypersenstivity to aspirin
  • Avoid use in pregnancy/breast feeding
  • Avoid use in children recovering from viral illness
  • Avoid use in patients with AIDS

Acute vs Chronic Constipation Duration

Acute

 

Self-Limiting

 

Chronic

 

> 12 weeks

Constipation Etiologies

1. Idiopathic

 

2. Primary

  • Normal transit
  • Slow transit
  • Outlet obstruction
  • Pelvic dysfunction

3. Secondary

  • GIT
  • Endocrine/Metabolic (DM)
  • Neurologic Disorders (MS, Parkinson’s disease)
  • Psychological
  • Ignoring urge
  • Medications

 

Medications that cause constipation

1.  Analgesics

  • Inhibitors of prostaglandin synthesis
  • Opiates

2.  Anticholinergics

  • Antihistamines
  • Antiparkinsonian agents (benztropine, trihexaphenidyl)
  • Phenothiazines
  • TCAs

3.  Antacids containing:

  • Calcium Carbonate
  • Aluminum Hydroxide

4.  Ca2+ Channel Blockers

  • Verapamil (most often)
  • Diltiazem

Symptoms (Red Flags) of Constipation That Require Referral

  • Blood in stool
  • N/V
  • Fever
  • Severe cramping, abdominal discomfort, pain
  • FH of IBS or colon cancer
  • Failure of self-care options

Bulk-Forming Laxatives: MOA, Indication, ADE, Rx-Rx, CI, Clinical Pearls

MOA

  • Dissolves/swells intestinal fluid

Indication

  • short-term therapy for relief of constipation, prophylaxis of constipation

ADE

  • Abdominal cramping, flatulence

Rx-Rx

  • Anticoagulants, digitalis glycosides, salicylates, tetracyclines

CI

  • Intestinal ulcerations
  • stenosis
  • disabling adhesions
  • fluid restricted patients
  • hypersensitivity to agent

Clinical Pearls

  • consider initial therapy for most forms of constipation
  • consume at least 8 oz of fluid for efficacy and decrease possibility of obstruction
  • Calcium polycarbophil has a great water binding capacity

Emollients: MOA, Indication, ADE, Rx-Rx, CI, Clinical Pearls

MOA

  • Increase wetting efficiency of intestinal fluid and facilitate mixture

Indication

  • Prophylaxis of constipation

ADE

  • Diarrhea, mild abdominal cramping

Rx-Rx

  • mineral oil — increased toxicity due to better absorption

CI

  • Avoid in patients with N/V, appendicitis, undetermined abdominal pain

Clinical Pearls

  • Increase fluid intake to facilitate stool softening

Saline Laxatives: MOA, Indication, ADE, Rx-Rx, CI, Clinical Pearls

MOA

  • Osmotic ions draw water into the intestine

Indication

  • No longer for acute bowel prep; only as PRN laxative

ADE

  • hypermagnesemia
  • abdominal cramping, N/V
  • excessive diuresis, dehydration

Rx-Rx

  • tetracyclines, digitalis glycosides, chlorpromazine, sodium polystyrene

CI

  • ileostomy
  • colostomy
  • dehydration syndromes
  • renal function impairment
  • CHF

Clinical Pearls

  • administer at least 8 oz fluid to prevent dehydration following oral use

Glycerin Suppository: MOA, Indication, ADE, Clinical Pearls

Hyperosmotic

 

MOA

  • Draws water into rectum, rectal stimulation

Indication

  • Lower bowel evacuation

ADE

  • rectal irritation

Acute Phosphate Nephropathy is caused by:

Saline Laxatives in patients with:

  • kidney disease
  • elderly patients (> 55)
  • drugs that affect renal perfusion pressure (ACEI, ARBs, NSAIDs, Diuretics)

Saline laxatives no longer used for acute evacuation (bowel prep)

Miralax Powder: MOA, Indication, ADE, Clinical Pearls

Hyperosmotic

 

MOA

  • Large, poorly absorbed ethylene glycol molecules have an osmotic effect leading to distension and catharsis

Indication

  • Occasional constipation

ADE

  • abdominal discomfort, flatulence, cramping

Clinical Pearls

  • Used for bowel prep

Senna: MOA, Indication, ADE, CI, Clinical Pearls

Stimulant Laxative

 

MOA

  • increase in motility

Indication

  • Bowel evacuation prior to procedure/surgery, chronic opiate-induced constipation

ADE

  • severe cramping, fluid/electrolyte deficiencies, hypokalemia
  • urine discoloration

CI

  • rectal bleeding, intestinal obstruction, appendicitis, pregnancy

Clinical Pearls

  • intensity of action is proportional to dose, individually effective doses vary
  • often abused

Bisacodyl: MOA, Indication, ADE, Rx-Rx, CI, Clinical Pearls

Stimulant Laxative

 

MOA

  • increase in motility

Indication

  • Bowel evacuation prior to procedure/surgery, chronic opiate-induced constipation

ADE

  • severe cramping, fluid/electrolyte deficiencies, hypokalemia

Rx-Rx

  • antacids, H2RA, PPIs, milk

CI

  • rectal bleeding, intestinal obstruction, appendicitis, pregnancy

Clinical Pearls

  • intensity of action is proportional to dose, individually effective doses vary
  • often abused
  • effective in patients with colostomies

Lubipristone: MOA, Indications, CI

MOA

  • local acting selective chloride channel activator
  • very little absorbed systemically — no known rx-rx interactions

Indications

  • chronic idiopathic constipation

CI

  • known GI obstruction

Patient education for constipation

  • Lifestyle changes may restore normal bowel function
  • Most OTC products should not be used for more than 1 week

IBS is defined as:

  • A GI syndrome characterized by chronic abdominal pain and altered bowel habits in absence of any organic disease
  • BOTTOM LINE: IBS patients demonstrate increased motor reactivity of the colon and SI to a variety of stimuli and altered visceral sensation associated with lowered sensation thresholds that may result from CNS-enteric nervous system dysregulation

Signs and Symptoms of IBS

  • Lower abdominal pain
  • Abdominal bloating and distension
  • Diarrhea symptoms, > 3 stools/day
  • Extreme urgency
  • Mucus passage
  • Constipation symptoms, < 3 stools/week, straining, incomplete evacuation
  • Psychological symptoms such as anxiety and depression

IBS Symptoms that require Physician Referral

  • Weight loss
  • Anemia
  • Family history of colon cancer
  • Onset at > 50 yrs of age
  • Rectal bleeding
  • Nocturnal symptoms

Flow Chart: Treatment for IBS-C

Increase dietary fiber and fluid intake

Add bulk-forming laxatives and consider antispasmodic agents

Add serotonin-4 agonists (tegaserod)

Add psychotherapeutic behavior modifications, including stress reduction, and consider antidepressants for associated pain symptoms

Flow Chart: Treatment for IBS-D

Lactose-free, caffeine-free diet.  Counsel on other drugs and food to avoid.

Add loperamide or other antispasmodic

Add serotonin-3 antagonists (alosetron)

Add psychotherapeutic behavior modifications, including stress reduction, and consider antidepressants for associated pain symptoms

Tegaserod: MOA, Indication

  • 5HT4 Agonist
  • For IBS-C
  • Only available for life-threatening situations

Alosetron: MOA, Indication

  • 5HT-3 Antagonist
  • For IBS-D

Amitiza: Indication
IBS-C

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