Therapeutics GI Petkewicz – Flashcards

• Spinal Energy
• Neuropathy (Diabetes)

• Crohn's Disease
• Ulcerative Colitis

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 

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

Causative Agents

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

Therapeutic Agents

• Vancomycin (PO)
• Metronidazole (Flagyl)

• 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

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

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

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

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

Self-Limiting

Chronic

> 12 weeks

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

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

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

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

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

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

Hyperosmotic

MOA

• Draws water into rectum, rectal stimulation

Indication

• Lower bowel evacuation

ADE

• rectal irritation

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)

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

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

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

MOA

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

Indications

• chronic idiopathic constipation

CI

• known GI obstruction

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

• 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

• 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

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

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

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

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

• 5HT-3 Antagonist
• For IBS-D