PHARM: Constipation and Diarrhea Flashcards by Rachael Petry

What type of laxatives are:
Psyllium hiusk
Semisynthetic celluloses
Plycarbophils

Dietary fiber (bulk forming laxatives)

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What type of laxatives are:
Docusates (dioctyl sodium sulfosucinate)
Poloxamers
Castor Oil

Surfactant Laxatives

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What type of laxatives are:
Diphenylmethanes
Anthraquinones

Stimulant laxatives

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What type of laxatives are:
Magnesium Containing Laxatives
Phosphate Containing Laxatives
Nondigestable Sugars/Alcohols (Lactulose, Glycerin, and polyethylene glycol solution)

Osmotic Laxatives

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What type of laxatives are:
Mineral Oil
Caster Oil

MIscellaneous laxatives

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What is the most potent class of laxatives?

stimulant laxatives

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Which stimulant laxative is a synthetic prodrug?

diphenylmethanes (converted by enteric bacteria into desacetyl active form)

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Which stimulant laxative is a natural laxative?

anthraquinones

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In a patient with diarrhea, what MUST be done before treating for diarrhea?

Stool culture needs to be taken before you treat! RULE OUT infection!

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Which diarrhea treatments act by absorbing water?

Cellulose Derivatives

Semisynthetic Polysaccharides

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Which diarrhea treatments are adsorbers of etiological factors in the lumen?

Bismuth Subsalicylate

Charcoal

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Which diarrhea treatments alter intestinal motility?

Opiods

Anticholinergics (antispasmodics)

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MOA: unabsorbed material that sucks water into the colon so that there is more water in the stool, increases bulk of stool, and reduces pressure in the sigmoid colon.

Psyllium Husk
Semisynthetic celluloses
Polycarbophils

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MOA: Salt that decreases the surface tension between the stools and rectal epithelium to result in easier passage of the stool. NO effect on peristalsis

Dioctyl Sodium Sulfosucinate

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What are surfactant laxatives used for?

stool softeners

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MOA: NON-ionic substance that decreases the surface tension between the stools and rectal epithelium to result in easier passage of the stool. NO effect on peristalsis

Poloxamers

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MOA: NON-ionic substance that decreases the surface tension between the stools and rectal epithelium to result in easier passage of the stool. STIMULATES peristalsis.

castor oil

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Which surfactant laxative is used for complete evacuation of the bowels (catharsis)?

Castor oil

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MOA: increase permeability of intestinal (colon) mucosa

Diphenylmethane and Anthraquinones (more gentle)

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What is the effect of increasing colonic mucosa?

leakage of the water back into the lumen after it is absorbed, increase the propulsive contractility of the colon (nerve plexus activation) and stimulate PG synthesis and increase intestinal secretions

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MOA: stay in intestine and draws water in (so it stays isoosmotic) to make stool more watery.

Magnesium sulfate
Magnesium Hydroxide
Magnesium Citrate
Sodium Phosphate

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What is the other MAJOR action of osmotic (Mg-containing) laxatives?

These also stimulate the release of CCK (increase motility and secretion).

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Which Mg-containing laxative is used for colonoscopy prep?

Magnesium citrate

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What other osmotic laxatives are used for colonoscopy prep (but can be ORAL or enema)?

sodium phosphate

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MOA: Semisynthetic disaccharide which is NOT absorbed and produces an osmotic laxative effect (metabolized by enteric bacteria into organic acids→ fecal acidification that traps ammonia in the non-toxic ammonium form.

Lactulose

MOA: Sugar alcohol that is used as suppository—stay in intestine and draws water in (so it stays isoosmotic) to make stool more watery

glycerin

MOA: Electrolytes stay in intestine and draws water in (so it stays isoosmotic) to make stool more watery and provide COMPLETE EVACUATION.

Polyehtylene glycol electrolyte solution | GOLYTELY

How and why is GOLYTELY taken?

Solution that is dissolved into 4L and ingested 8 oz every 10 minutes for colonoscopy

MOA: Mixture of hydrocarbons that penetrates and softens the stool.

Mineral oil

MOA: Emulsion that irritates the mucosa and produces a cathartic effect.

castor oil

MOA: Activates intestinal Cl- channels in a PKA-independent fashion. Activation of these channels increases intestinal fluid secretion and motility and alleviates the symptoms associated with chronic idiopathic constipation.

lubiprostone

MOA: Peptide agonist of guanylate cyclase 2C that acts on intestinal cells to indirectly activate the Cl- channel (cGMP made from GTP to activate PKG II which activates channel)

Linaclotide

MOA: Adsorbs harmful bacteria, viruses or toxins that cause diarrhea.

Bismuth Subsalicylate

MOA: OVERALL increase contact time between ingested material and reabsorptive intestinal epithelium!

Paregoric Diphenoxylate with Atropine Loperamide

What diarrhea treatment is esentially grinded up opiates?

paregoric

What diarrhea treatment is a mixture of opiate and anti-cholinergic to reduce dose and abuse?

Diphenoxylate with Atropine

What diarrhea treatment is an opiate that inhibits calmodulin (Ca2+ binding protein)?

Loperamide

How do opiates prevent diarrhea?

- Decrease secretions (salivary, gastric, and intestinal) - Decrease motility (stomach, intestines), - Increase muscle tone - Increase tone of intestinal sphincters (including external anal sphincter→ reduce urgency) - Act as antispasmodics (decrease cramps)

MOA: Block cholinergic receptors and reduce vagal stimulation—antispasmodic!

Propantheline | Dicyclomine

What type of drugs are propantheline and dicyclomine?

Quaternary ammonium derivatives of atropine (do NOT cross BBB).

What is the indication for propantheline and dicyclomine?

reduce cramps

What drug is an Anticholinergic + benzodiazepine?

Librax

What is the indication for Librax?

Cramps and Anxiety

Describe the cause of cyclical laxative use.

Over time, the overuse of laxatives leads to thorough constipation that requires several days to accumulate bulk (this lag is interpreted by patient as continued constipation so this encourages them to take more).

True or false: over time, the bowel can become unresponsive to laxatives.

TRUE

TOXICITY: Allergic rxn, flatulence, borborygmi, obstruction, may inhibit coumarin absorption

Psyllium husk

TOXICITY: May bind and impede drug absorption

Semisynthetic celluloses

Which type of laxative is CONTRAINDICATED with tetracyclines because it releases calcium?

Polycarbophils

What drugs are NOT for use with abdominal pain, N/V?

Dioctyl Sodium Sulfosucinate | Poloxamers

Why can Dioctyl Sodium Sulfosucinate only be used for a short time?

over time, it may injure the epithelium/intestinal mucosa and lead to malabsorption or increased absorption of various drugs

TOXICITY: diarrhea

Poloxamers

What laxative is contraindicated in pregnancy?

castor oil (can induce uterine contractions)

Which drug can cause colic, dehydration, and electrolyte imbalance if overdosed?

castor oil

What drug can cause excessive fluid and electrolyte loss (intestinal enterocyte damage leading to colonic inflammatory response) in overdose?

Diphenylmethanes

TOXICITY: Large doses can cause abdominal pain nephritis, melanotic (dark) pigementation of colonic mucosa, and abnormal urine coloration

anthraquinones

What drugs are used in the treatment of inflammation from IBD?

Glucocorticoids

What types of targeted therapy can be used with IBD?

Anti-TNF-alpha based therapy

Which drug is a monoclonal antibody against TNF-alpha that binds to TNF-alpha in the blood and this decreases the inflammation?

infliximab

What do you usually administer with infliximab?

immunosuppressive therapy (ex. mercaptopurin)

What drug is a fusion protein containing the ligand binding portion of TNF-alpha receptor linked to Fc portion of human IgG1?

etanercept

What do you usually administer with etanercept?

NOTHING, does not require concomitant immunosuppression

What drug is a humanized mAb to TNF-alpha?

adalimumab

MOA: inhibits certain immune cell molecules from binding to cells in the intestinal lining to decrease production of antibodies

Natalizumab

What type of immune cell molecules does Natalizumab target? What is their MOA?

integrins- usually tell B cells to secrete more antibodies

What is the purpose of giving 5-Aminosalicylic Acid Derivatives in IBD?

deliver aspirin deep into the intestinal crypts to reduce inflammation

MOA: enteric coated tablets that are broken down by intestinal bacteria into 5-ASA and sulfapyridine

Sulfasalazine

What is the role of 5-ASA (breakdown product of sulfasalazine)?

aspirin that gets released into the crypt where it inhibits PG synthesis and inflammation

What is a negative aspect of sulfasalazine?

sulfapyridine (breakdown product) causes side effects like anemia, rash and impotence

What is the difference between sulfasalazine and dimer 5-ASA Mesalalamine?

with 5-ASA-Mesalalamine, you get more sulfapyridine than 5-ASA (worse IMPOTENCE)

What drug for IBD is a immune suppressant anti-metabolite?

Mercaptopurine

What drugs are used to keep portal systemic encephalopathy patients alive long enough for transplant?

Rifaximin | Lactulose

Why do you use Rifaximin to treat PSE?

locally acting (not absorbed) antibacterial given orally for 14 days to reduce bacteria in the colon (so less ammonia made)

Why do you use lactulose to treat PSE?

acidifies the stool so that ammonia can be converted into ammonium (not absorbed). This will have an osmotic laxative effect

Inner ear motion is transmitted via what nerve?

8th CN

What signaling molecules/receptors work to transmit inner ear motion?

cholinergic receptors (Ach and histamine)

What is the role of the chemoreceptor trigger zone?

analyze composition of CSF

What nerves tell the vomiting center about the status of the intestines?

Visceral afferents (along vagal and sympathetic nerves)

What receptors/neurotransmitters are used by visceral afferents from the intestines to the vomiting center?

5-HT3 using serotonin receptors

What is responsible for processing horrific sights, smells, pain, etc. to lead to nausea and vomiting?

limbic system

MOA: Blocks cholinergic fibers of the auditory nerve from activation by Ach (no signaling the CTZ)

Scopolamine

What is the indication for scopolamine?

motion sickness

MOA: Anti-cholinergic effects in addition to antihistaminic (H1) effects

Dimenhydrinate Cyclizine Meclizine Promethazine

Which H1 antihistamine is for use with motion sickness (OTC prophylaxis 30-60 min before trip)?

Dimenhydrinate

Which H1 antihistamines are used for vestibular disturbances like Vertigo or Menier’s disease (by depressing hyperstimulation of labrynth function)?

Cyclizine | Meclizine

Which H1 antihistamine is used for nausea and vomiting?

Promethazine

Which H1 antihistamine is VERY sedative?

Promethazine

MOA: Block dopamine receptors in the chemo-receptor trigger zone.

``` Chlorpromazine Prochlorperazine Thiethylperazine Droperidol Trimethobenzamide ```

Which antidopaminergic also inhibits the vomiting center?

Thiethylperazine

What is special about chlorpromazine?

antidopaminergic and anticholinergic

What is the indication for chlorpromazine?

N/V and intractable hiccups

Which antidopaminergic is used post-operatively to treat N/V?

Droperidol

Which antidopaminergics have extrapyramidal side effects and are for short term use ONLY?

Droperidol | Trimethobenzamide

What are the adverse effects seen with scopolamine?

Sedation, extrapyramidal (drowsiness, dry mouth)

MOA: Blocks chemo-iactivation of D2 receptors in CTZ; stimulates gastric emptying

metoclopramide

What is the indication for metoclopramide?

Given post-op for N/V; prophylaxis for chemo.

What drug class is the CORNERSTONE OF DRUG THERAPY IN CHEMOTHERAPY PATINETS?

serotonin antagonists

What are the serotonin antagonists

Ondansetron Granisetron Dolasetron Palonosetron

How do serotonin antagonists prevent vomiting?

Block 5-HT3 receptors in stomach and small intestines that transmit stimuli through vagal/ sympathetic afferents to the CTZ and VC through solitary tract nucleus. Block 5-HT3 receptors in CTZ immediately involved in stimulating VC with emesis

What is the ONLY selective 5-HT3 antagonist that prevents emesis by high dose cytotoxic drugs (cis-platinum and radiation)

ondansetron

Which serotonin antagonist is more potent than ondansetron?

granisetron

Which serotonin antagonist has the longest half-life?

Dolasetron

Which serotonin antagonist is given IV for N/V associated with chemotherapy?

palonosetron

MOA: Stimulates CB-1 subtype of cannabinoid receptors

Dronabinol (marijuana)

MOA: Prevent production of PGs associated with chemo/radiation

dexamethasone

MOA: Weak, central Substance P/ neurokinin 1 receptor antagonist that crosses BBB

aprepitant

TOXICITY: Psychomimetic reactions; abuse

dronabinol (marijuana)

What are the conditions for the treatment of dronabinol?

Antiemetic in chemo ONLY if patients don’t respond to other therapy

What drug class is given to chemo patients with anticipatory emesis?

benzodiazepines

Name the benzodiazepines used as antiemetic adjuncts?

Lorazepam | Alprazolam

What is the effect of benzodiazepines?

Cause somnolence and amnesia lasting for hours. Anti-anxiety

PHARM: Constipation and Diarrhea Flashcards

(110 cards)