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Treatment of Constipation and Diarrhea UPDATED
Pharm Assessment 9
60
Pharmacology
Graduate
11/13/2011

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Cards

Term
What is coupled to Na+ entry into the villous enterocyte?
Definition
absorption of glucose and amino acids
Term
How is electrical neutrality maintained in the enterocyte?
Definition
movement of Cl- from the lumen through intercellular spaces to the interstitial compartment
Term
How is Na+ extruded from the enterocytes?
Definition
by Na+,K+ATPase located in the basolateral membrane
Term
What factors Enhance fluid absorption in the colon?
Definition
Short-chain fatty acids
Aldosterone (enhanced Na+ uptake)
Somatostatin
antidiuretic hormones
dopaminergic agonists
adrenergic agonists
Term
What factors Reduce fluid absorption in the colon?
Definition
Long-chain fatty acids
dihydroxy bile acids
cholinergic agonists
prostaglandins
vasoactive intestinal peptide
cholera toxin (cAMP activation)
Term
What factors can cause constipation?
Definition
Excessive water reabsorption
Decreased Motility
Term
What factors can cause diarrhea?
Definition
Increased motility
Excessive Secretion
Decreased absorption
Term
What are the 5 groups of Laxatives?
Definition
Dietary Fiber and Bulk-forming laxatives
Surfactant laxatives
Osmotic Laxatives
Stimulant Laxative
Miscellaneous laxatives
Term
Dietary Fiber and Bulk-forming Laxatives
Definition
Psyllium husk
Semisynthetic celluloses
Polycarbophils
Term
Effer-syllium
Metamucil
Definition
Psyllium Husk

Hydrophilic muciloid that forms getatinous mass when mixed with water
Term
Citrucel
Cologel
Definition
Semisynthetic celluloses

Hydrophilic and digestible
Forms a colloid mass with water

(Citrocel and Cologel form Colloid)
Term
What bulking agent may inhibit coumarin absorption?
Definition
Psyllium husk
Term
Which bulking agent can cause allergic reactions, flatulence, and intestinal obstruction?
Definition
Psyllium husk
Term
What bulking agent can cause borborygmi?
Definition
Psyllium Husk
Term
Which Bulking agent may bind and impede drug absorption?
Definition
Semisynthetic celluloses
(Citrucel and Cologel)
Term
Surfactant Laxatives
Definition
Docusate Sodium
Castor Oil
Term
What Surfactant Laxative is weakly acting Anionic Surfactant?
Definition
Docusate
Term
What Surfactant Laxative is not to be used during abdominal pain, nausea, or vomiting?
Definition
Docusate
Term
What Surfactant Laxative can irritate the intetinal mucosa and increase intestinal absorption of other drugs?
Definition
Docusate
Term
What surfactant laxative stimulates intestinal peristalsis?
Definition
Castor Oil
Term
How does Castor oil work?
Definition
Hydrolyzed to Ricinoleic Acid-> produces catharsis-> complete evacuation of bowels
Term
What surfactant can induce uterine contraction in pregnant women?
Definition
Castor Oil
Term
What are the most potent laxatives?
Definition
Stimulant Laxatives
Bisacodyl
Senna
Term
What is the mechanism of action of the stimulant laxatives?
Definition
a. Act on Large Bowel
b. Increase permeability of intestinal mucosa
c. Increase Back diffusion of water and electrolytes
d. Increase propulsive contractility of colon by stimulating colonic mucosal myenteric plexus
e. Stimulate prostaglandin synthesis and increase intestinal secretions
Term
What stimulant laxative is a prodrug that is converted by enteric bacteria into it's active form?
Definition
Bisacodyl
Term
What Stimulant Laxatives act by promoting colonic motility?
Definition
Senokot (Senna)
Term
What Stimulant laxative can cause melanotic pigmentation of the colonic mucosa in large doses?
Definition
Senna
(Senokot)
Term
How do Saline laxatives work?
Definition
Laxatives containing magnesium cations or other nonabsorbable molecules
Exert an osmotic effect which retains water in the lumen of the GI tract
Term
What are the Magnesium containg laxatives? How do they work?
Definition
Magnesium sulfate: Epsome Salt
Magnesium hydroxide: Milk of Magnesia
Magnesium citrate: Citroma (cathartic)

Osmotic effect and release of CCK-> increases motility and secretion
Term
How are Posphate containing laxatives administered?
Definition
Enema
Fleet Enema
Oral Sodium Phosphate tablets (Visicol, OsmoPrep)
Term
What are the Nondigestible sugars and alcohols?
Definition
Lactulose (Cephylac)
Polyethylene glyco
Term
How does Lactulose work?
Definition
Produces Osmotic effect
Metabolized by enteric bacteria to organic acids-> lactic, formic and acetic acid
Fecal Acidifier-> traps ammonia in ammonium form (non-toxic)
Term
What laxative is a mixture of hydrocarbons that penetrates and softens the stool?
Definition
Mineral Oil
Term
What are some general side effects of laxative abuse?
Definition
Overuse leads to thorough constipation that requires several days to accumulate bulk
Lag in defecation is interpreted as continued constipation
Take more laxatives-vicious cycle
Bowel becomes unresponsive
Term
What are the 3 groups of Antidirrheal agents?
Definition
Agents that absorb water
Absorbers of etiological factos in the lumen
Agents that alter intestinal motility
Term
What antidirrheal agents are used to absorb water?
Definition
Cellulose derivatives
Semisynthetic polysaccharides
(metamucil)
Term
How do Bismuth subsalicylate, charcoal, Attapulgite, and Magnesium Aluminum Disilicate work as antidirrheal agents?
Definition
Adsorb harmful bacteria, viruses, or toxin.
Term
How do Opiates work as antidirrheal agents?
Definition
*Increase contact time between ingested matter and the reabsorbtive intestinal epithelium*

Decrease salivary, gastric and intestinal secretions
Decrease motility of stomach and intestines
Increase muscle tone
Increase sphincter tone(reduce urgency)
Anti-spasmodics - decrease cramps
Term
What Opioid is formulated for diarrhea?
Definition
Loperamide
Term
What Opioid interacts with intestinal opioid receptors and binds to and inhibits the calcium-binding protein calmodulin?
Definition
Loperamide
Term
What opioid should not be used in Ulcerative colitis?
Definition
Loperamide
Term
What is the mechanism of action of the anticholinergic antidirrheal agents?
Definition
Block cholinergic receptors and reduce vagal stimulation.
Anti-spasmodic
Term
What type of drugs are used in the treatment of motion sickness?
Definition
Anticholinergics
H1 antihistamines
Term
What is the mechanism of action of Scopolamine?
Definition
Anticholinergic
Blocks activation of muscarinic receptors by acetyl choline, to inhibit cochlear sensation of motion projected via cholinergic fibers of the auditory canal to the CTZ
Term
What are some side effects of Scopolamine?
Definition
Sedation, dry mouth
Term
What is the mechanism of H1 antihistamines on the treatment of motion sickness?
Definition
Older Antihistamines exhibit anti-cholinergic effects in addition to H1 effects
Term
What is the H1 antihistamines used for motion sickness?
Definition

Dimenhydrinate

Term
What H1 agent is used for prophylaxis of motion sickness?
Definition
Dimenhydrinate (Dramamine)
Term
What is the Antidopaminergics used as antiemetics?
Definition

Chlorpromazine

Term
What is the mechanism of the Antidopaminergics?
Definition
Block dopamine receptors in the CTZ
Term
What Antiemetic is used for N&V and intractable hiccough?
Definition

Chlorpromazine

(anticholinergic and antidopaminergic)

Term
What antiemetic is a centrally acting anticholinergic and antidopaminergic?
Definition
Chlorpromazine
Term
What are the side effects of Antidopaminergics?
Definition
Extrapyramidal - Dystonias
(short-term use)
Term
What are the most effective antiemetics?
Definition
Serotonin antagonists
Term
How do the antiemetic serotonin antagonists work?
Definition
Block 5-HT3 receptors in the stomach and small intestines
Block 5HT3 receptors in the CTZ that are involved in stimulating the VC to produce emesis
Term
What are the Serotonin Antagonists?
Definition
Ondansetron
Granisetron
Term
What antiemetic drug is used to prevent emesis induced by cytotoxic agents like cisplatin?
Definition
Aprepitant
Term
What drug is give via a transdermal patch behind the ear? What it is it's mechanism?
Definition

Scopolamine

 

Anticholinergic - blocks muscarine receptors on CNVIII travelling to the CTZ

Term
Why are corticosteroids (dexamethasone and methyl prednisolone) used in combo with other antiemetics?
Definition
Enhance antiemetic effects and reduce side effects of other drugs
Term
What antiemetic is a Substance P/Neurokinin 2 receptor antagonist?
Definition

Aprepitant

 

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