Flashcards in Pharm GI drugs 2 Deck (63)
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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
3
what is used to treat persistent symptoms of GERD?
-alginic acid antacids
-promotility drugs (cisapride or metoclopramide)
-H2 receptor blockers (-tidines)
4
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
5
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
8
domperidone mechanism, treats, SE
-mechanism: improves gastric tone
-treats: gastroparesis
-SE: none listed
9
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
12
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.)
15
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)
25
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
28
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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