Flashcards in Pharm GI drugs 2 Deck (63):
1
GERD pathophys
-lower esophageal sphincter disorder (inappropriate relaxation, low resting tone, anatomical alteration)
-acid hyper secretion (esp after meals)
-decreased acid clearance due to impaired peristalsis or abnormal saliva production
-delayed gastric emptying and/or duodenogastric reflux of bile salts and pancreatic enzymes
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lifestyle measures for treatment of GERD
-elevation of the head of the bed
-avoidance of food or liquids 2-3 hr before bed
-avoidance of fatty or spicy food, cigarettes, alcohol
-weight loss
-liquid antacid
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what is used to treat persistent symptoms of GERD?
-alginic acid antacids
-promotility drugs (cisapride or metoclopramide)
-H2 receptor blockers (-tidines)
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what is used to treat non response or relapse or barrett's?
-H2 receptor blocker - regular or double dose
-H2 receptor blocker + promotility agent
-proton pump inhibitors (-prazole)
-antireflux surgery
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what are the promotility drugs?
-metochlopramide (peripheral dopamine antagonist)
-cisapride (dopamine antagonist)
-domperidone
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metochlopramide mechanism, treats, SE
-increases motor tone in lower esophageal sphincter and stomach - also peripheral and CNS (vomiting) dopamine antagonist
-treats: GERD, anti-emetic, gastroparesis
-SE: hand tremor, possible extra-pyramidal
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cisapride mechanism, treats, SE
-mechanism: increases motor tone in lower esophageal sphincter and stomach
-treats: GERD, gastroparesis
-SE: sudden cardiac death
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domperidone mechanism, treats, SE
-mechanism: improves gastric tone
-treats: gastroparesis
-SE: none listed
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pathophys of vomiting
-mediated by chemo receptor Trigger Zone (CRTZ) and vomiting center in the medulla
-stimulated by: local irritation of stomach (drugs, alcohol, infection), CNS stimulation (infection, inflammation, mass effects, headache and drugs), pain
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what are the metabolic consequences of vomiting?
dehydration, electrolyte disturbances
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what is used for treatment of vomiting?
antiemetics (central actions of CRTZ)
1. phenothiazines
2. benzamide derivatives
3. tetrahydro cannabinol
4. serotonin receptor antagonists
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what are the phenothiazines?
1. prochlorperazine
2. prometazine
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prochlorperazine mechanism
probable CNS interaction with dopaminergic receptor-antagonist (leading to reduction of stimulation in the CRTZ in the medulla)
ANTI-EMETIC - phenothiazine
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prochlorperazine SE
extra pyramidal (torticollis - the neck muscles contract, causing the head to twist to one side.)
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promethazine mechanism
(antihistaminic H1 receptor) - anticholinergic
ANTI-EMETIC - phenothiazine
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what are the benzamide derivatives? what are their SE?
1. trimethobenzamide
2. metochlopramide
SE: extra pyramidal symptoms
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trimethobenzamide mechanism
unknown effect on CRTZ
ANTI-EMETIC - benzamide derivative
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trimethobenzamide SE
low-side effect profile; possible extra-pyramidal symptoms
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metochlopramide mechanism
CNS and peripheral dopaminergic receptor antagonism
ANTI-EMETIC, GERD, gastroparesis use
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tetrahydro cannabinol mechanism
THC - suppress the CRTZ by probable anticholinergic mechanism
ANTI-EMETIC
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what are the serotonin receptor antagonists?
-SETRON!!!
1. ondansetron
2. granesitron
3. dolasetron
used as anti-emetics
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serotonin receptor antagonists SE
headache, dizziness, somnolence
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what is gastroparesis?
outlet obstruction and/or loss of gastric tone (e.g. DM)
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what is used in treatment of gastroparesis?
promotility drugs (metochlopramide, cisapride, domperidone)
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what are the 5 types of diarrhea?
1. acute diarrhea
2. traveler's diarrhea
3. chronic and recurrent diarrhea
4. chronic diarrhea of unknown origin
5. incontinence
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what are the causes of acute diarrhea?
1. viral, bacterial, parasitic infection
2. food poisoning
3. drugs (acute or chronic)
4. fecal impaction
5. heavy metal poisoning (acute or chronic)
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what are the causes of traveler's diarrhea?
1. bacterial infections (enterotoxins, invasion of mucosa and inflammation)
2. viral and parasitic infections
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what is the mechanism of toxin mediated diarrhea?
increased production of cAMP = more Cl in lumen = osmotic diarrhea
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what are the causes of chronic and recurrent diarrhea?
1. irritable bowel syndrome
2. inflammatory bowel disease
3. parasitic infections
4. malabsorption syndromes, lactase deficiency
5. drugs (acute or chronic)
6. heavy metal poisoning (acute or chronic)
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what are the causes of chronic diarrhea of unknown origin ?
1. surreptitious laxative abuse
2. irritable bowel syndrome
3. unrecognized inflammatory bowel disease
4. bile acid malabsorption
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what are the causes of incontinence?
1. sphincter dysfunction (anal surgery, episiotomy or tear during childbirth, anal crohn's, diabetic enuropathy, idiopathic)
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what are the goals of diarrhea treatment?
decrease GI secretion - present less fluid to colon
and decrease GI motility - more time for reabsorption of water and decrease cramps
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what drug classes are used for treatment of diarrhea?
1. anticholinergics
2. opioid agonists
3. colloids and pectins
4. antibiotics
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anticholinergic drugs and mechanism for treatment of diarrhea
atropine sulfate
-relax all bowel smoothe uscle
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opioid agonists drugs and mechanism for treatment of diarrhea
loperamide, diphenoxylate, codeine sulfate
-these drugs have less penetration to CNS - interact with mu or sigma receptors in GI tract
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difference between loperamide and diphenoxylate / codeine sulfate
diphenoxylate and codeine sulfate combined with atropine which relaxes bowel smooth muscle
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what is the contraindication for diphenoxylate and codeine sulfate?
children (respiratory suppression)
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colloids and pectins: drugs and mechanism for treatment of diarrhea
metamucil (colloid) and kaopectate (pectin)
-absorb water but don't prevent potential dehydration
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risk of metamucil and kaopectate (colloid and pectin)
doesn't prevent potential dehydration
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what is used for treatment of constipation?
1. irritants/stimulants
2. osmotic cathartics
3. bulk-forming (hydrophilic colloids)
4. lubricant and fecal softeners
5. receptor active agents
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what are the irritants/stimulants used for constipation?
1. castor oil
2. cascara sagrada
3. senna extract
4. bisacodyl
5. phenolphthalein
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what are the osmotic cathartics used for constipation?
1. magnesium citrate
2. magnesium sulfate (epsom salt)
3. sodium sulfate
4. milk of magnesia
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what are the bulk-forming hydrophilic colloids?
1. psyllium seed
2. methylcellulose
3. sodium carboxymethylcellulose
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what are the lubricants and fecal softeners used for constipation?
1. mineral oil
2. dioctyl sodium sulfo-succinate
3. poloxalkol
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what are the receptor active agents? what are their mechanisms?
1. lubiprostone (chloride channel activator - osmotic)
2. linaclotide (stimulates cGMP resulting in chloride and bicarb secretion)
3. naloxegol (mu opioid receptor antagonist)
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when is naloxegol used?
for people on chronic opioids (mu opioid receptor antagonist)
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inflammatory bowel disease pathophys
all are idiopathic (probably autoimmune)
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crohn's disease
inflammatory bowel of the small bowel, especially ileum
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ulcerative colitis
inflammatory bowel of large bowel
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granulomatous (crohn's) colitis
inflammatory bowel large bowel
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acute therapy for inflammatory bowel disease
1. anti-inflammatories
2. corticosteroids
3. antibiotics
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what are the anti-inflammatories used in inflammatory bowel disease?
1. mesalamine (delayed release -used for terminal ileum)
2. sulfasalazine (toxicity from systemic absorption of sulfapyridine)
3. olsalazine (less toxic than sulfasalazine)
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which corticosteroid is used in inflammatory bowel disease?
prednisone (systemically or as enema)
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what are the immunosuppressive agents used for chronic therapy of inflammatory bowel disease?
1. azathioprine (purine antimetabolite)
2. corticosteroids (prednisone, decadron)
3. methotrexate
4. anti TNFa antibodies
5. anti-integrin antibodies
6. cyclosporine (suppresses T helper and T suppressor lymphocytes)
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what is used for chronic therapy of inflammatory bowel disease?
immunosuppressive agents
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what are the anti TNFa antibodies?
infliximab, adalimumab, certolizumab
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what are the anti-integrin antibodies?
natalizumab, vedolizumab, ustekinumab
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what are the contributing causes of irritable bowel syndrome?
psychosocial factors, altered motility, and altered sensation
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what are the drug classes used to treat irritable bowel syndrome?
1. anticholinergics (antispasmodic)
2. serotonergic antagonist
3. serotonergic agonist
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what are the anticholinergics used to treat irritable bowel syndrome?
1. dicyclomine HCl
2. hyoscyamine sulfate
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what is the serotonergic antagonist used to treat irritable bowel syndrome? what does it block?
alosetron - blocks 5HT3
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side effect of alosetron
ischemic bowel and constipation (no longer used)
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