GI Drugs II Flashcards
what are neostigmine and bethanechol used for
neostigmine: colonic pseudo obstruction in hospitalized patient
bethanechol: bowel and bladder retention post op
mechanism and use of erythromycin
acts on motilin receptors of GIT –> used for GI emptying before upper GI procedure
major categories of anti emetics
5 ABCCD HN
5HT3 antagonists Antimuscarinics Benzodiazepines Corticosteroids Cannabinoids D2 antagonists H1 antagonists NK1 antagonist
what are the 5-HT3 blockers used as anti emetics
Ondansetron
Granisetron
when are 5 HT3 blockers anti emetics used?
chemo induced emesis
post op nausea and vomiting
what are the H1 blockers and Antimuscarinic anti emetics used and when used?
H1 blocker: Diphenhydramine, Meclizine, Cyclizine for motion sickness and chemo
Antimuscarinics: scopolamine for motion sickness
what are the NK1 blockers used for anti emetics
Aprepitant
Fosaprepitant
adverse effects of NK1 antagonists (name them again)
aprepitant and fosaprepitant
dizziness, fatigue, diarrhea, CYP inhibition
corticosteroids anti emetics
Dexamethasone
Methylprednisolone
D2 receptor antagonist anti emetics
PPD
Prochlorperazine
Promethazine
Droperidol
adverse effects of prochlorperazine
extrapyramidal symptoms, hypotension, sedation
benzodiazepines anti emetics
LAD
Lorazepam
Alprazolam
Diazepam
benzos do not work too well as anti emetics so what then is their significant uses
sedative, anxiolytic, and amnesic properties
cannabinoid anti emetic and what it works on
Dronabinol - CB1 receptor agonist
what are the antidiarrheal drugs
SOB i shit my pants
Somatostatin analogs - Octreotide
Opioid agonist - Loperamide and Diphenoxylate
Bismuth compounds - Bismuth Subsalicylate
how do the opioid agonist anti diarrheals work (name them)
Loperamide and Diphenoxylate
-slow down gut motility by acting on GI mu-opioid receptor –> inhibition of acetylcholine release and decreased peristalsis
adverse effect of opioid agonists antidiarrheals (name them)
Loperamide and Diphenoxylate
- toxic megacolon in those with severe colitis
- Diphenoxylate is formulated with atropine to reduce abuse potential but high doses can cause CNS effects
mechanism of the somatostain antidiarrheal (name it) and types of pts that use it
Octreotide
potent inhibitor of GH, glucagon, and insulin
diarrhea and flushing in carcinoid syndrome and diarrhea in VIPoma
what is bismuth subsalicylate used for
- mucosal lining protectant (antacid)
- antidiarrheal
- decrease inflammation binds to toxins (E coli)
classify the laxatives by their mechanisms of action
-BOSCOS Bulk forming Osmotic Stimulants Chloride channel activator Opioid antagonist Softeners
what are the stimulant laxatives and their adverse effects
CBS
Castor oil, Bisacodyl, Senna
cause cramping and chronic use leads to perceived need for laxative
what are the bulk forming laxatives and their mechanism
BPM
Bran, Psyllium, Methylcellulose
non soluble compounds that increase water retention leading to bulky stool –> distention of the bowel –> peristaltic stimulation of gut
What are the osmotic laxatives
PLOMM
Polyethylene Glycol Lactulose Osmotic Magnesium Hydroxide Magnesium Salts
how do the osmotic laxatives work
they pull water into lumen of GIT –> stimulates motility
uses of Lactulose
- as an osmotic laxative by forming lactic acid and acetic acid which increases osmotic effect
- treatment of hepatic encephalopathy –> converts ammonia to ammonium so it can be excreted from body and prevent hyperammonia
when is polyethylene glycol used
endoscopic and radiological procedures
what are the softener laxatives
DoMGS
Docusate
Mineral oil
Glycerine
Softeners
use of glycerine and side effect
used for enema and can cause irritate anal mucosa
how do you treat opioid induced constipation
Senna and decusate
chloride channel activator laxative and mechanism
Lubiprostone –> increases secretion into GI –> increases fluid content
opioid receptor antagonist laxative
Alvimopan
Methylnaltrexone
drugs used in Inflammatory Bowel Disease (Ulcerative Colitis and Crohns)
AAGI
Anti TNFalpha drugs Anti Integrins Aminosalicylates Glucocorticoids Immunosuppressants
what are the aminosalicylates and their mechanism
BAMS
Balsalazide
Aminosalicylates
Mesalamaine
Sulfasalazine
inhibit pro inflammatory mediators IL-1 and TNFalpha
in the GIT, what is released by sulfasalazine by colonic bacteria
- sulfapyridine (antibacterial)
- 5 aminosalicyclic acid (5 ASA) (anti-inflamm)
adverse effects of sulfasalazine
HeRS
Hypersensitivity to sulfa
Reversible Oligospermia
Suppression of bone marrow (related to the sulfapyridine)
mechanism of balsalazide
releases mesalamine (5 ASA) in large intestine at site of ulcerative colitis
glucocorticoids used in IBD and mechanism
Hydrocortisone
Prednisolone
Prednisone
Budesonide
inhibit IL-1, IL-8, and TNFalpha
immunosuppressant used in IBD and mechanism
Methotrexate (MTX)
Azathioprine (prodrug of 6-MP)
Mercaptopurine (6-MP)
mechanism of immunosuppressant used in IBD (name them)
MTX, Azathioprine, 6-MP
6-MP promotes apoptosis of immune response
MTX blocks dihydrofolate reductase (DHFR)
adverse effects of immunosuppressants of IBD (name them)
MTX, Azathioprine, 6-MP
GI mucositis, myelosuppression, hepatotoxicity (6-MP)
