PHARM: Constipation and Diarrhea Flashcards
What type of laxatives are:
Psyllium hiusk
Semisynthetic celluloses
Plycarbophils
Dietary fiber (bulk forming laxatives)
What type of laxatives are:
Docusates (dioctyl sodium sulfosucinate)
Poloxamers
Castor Oil
Surfactant Laxatives
What type of laxatives are:
Diphenylmethanes
Anthraquinones
Stimulant laxatives
What type of laxatives are:
Magnesium Containing Laxatives
Phosphate Containing Laxatives
Nondigestable Sugars/Alcohols (Lactulose, Glycerin, and polyethylene glycol solution)
Osmotic Laxatives
What type of laxatives are:
Mineral Oil
Caster Oil
MIscellaneous laxatives
What is the most potent class of laxatives?
stimulant laxatives
Which stimulant laxative is a synthetic prodrug?
diphenylmethanes (converted by enteric bacteria into desacetyl active form)
Which stimulant laxative is a natural laxative?
anthraquinones
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!
Which diarrhea treatments act by absorbing water?
Cellulose Derivatives
Semisynthetic Polysaccharides
Which diarrhea treatments are adsorbers of etiological factors in the lumen?
Bismuth Subsalicylate
Charcoal
Which diarrhea treatments alter intestinal motility?
Opiods
Anticholinergics (antispasmodics)
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
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
What are surfactant laxatives used for?
stool softeners
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
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
Which surfactant laxative is used for complete evacuation of the bowels (catharsis)?
Castor oil
MOA: increase permeability of intestinal (colon) mucosa
Diphenylmethane and Anthraquinones (more gentle)
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
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
What is the other MAJOR action of osmotic (Mg-containing) laxatives?
These also stimulate the release of CCK (increase motility and secretion).
Which Mg-containing laxative is used for colonoscopy prep?
Magnesium citrate
What other osmotic laxatives are used for colonoscopy prep (but can be ORAL or enema)?
sodium phosphate
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