GI pharm Flashcards
sodium bicarbonate
Alka seltzer Mech: obsolete antacids, drugs neutralizing gastric acid Pharm: fast acting, short duration Side effect: belching, flatulence Uses: occasional dyspepsia
Calcium carbonate
Tums
Mech: obsolete antacids, drugs neutralizing gastric acid
Pharm: fast acting, short duration
Side effect: rebound increase H+ secretion
Uses: occasional dyspepsia
Magnesium hydroxide and aluminum hydroxide combo
Mylanta, Maalox
Mech: antacid. drug neutralizing gastric acid
Pharm: fasting acting, short duration
Contraindicated: renal insufficiency
Side effect: minimal toxicity, diarrhea (Mg), constipation (Al)
Uses: occasional dyspepsia
Simethicone
Anti foaming agent
Mech: added to reduce esophageal reflux
Proton pump inhibitors
Mech: reduce gastric acid secretion, most useful
- may interfere with gastric absorption of some drugs that are acidic or weak bases
Pharm: takes a couple of days
histamine 2 receptor blockers
Less effective than proton pump inhibitors
Pharm: faster onset than proton pump inhibitors
Mech: reduce gastric acid secretion
- may interfere with gastric absorption of some drugs that are acidic or weak bases
Antimuscarinic agents
Less effective at reducing gastric acid
- may interfere with gastric absorption of some drugs that are acidic or weak bases
Omeprazole, esomeprazole, lansoprazole
Mech: proton pump inhibitors
Pharm: once a day dosing, prodrugs
- give on empty stomach
- concentrates in canaliculi of parietal cells via acid trapping
- converted to active form for irreversible block
Side effects: slight increase in GI infections, short half life not a lot of drug interactions
Uses: first line treatment for GERD, ulcers, NSAID ulcers
- also prevent stomach bleeding
- H pylori treatment with antibiotics
Cimetidine, ranitidine, famotidine
Mech: histamine blockers
Pharm: faster onset, less effective than PPIs
Side effects: cimetidine has many drug interactions (CYP inhibitors) and weak inhibition of androgen receptors otherwise safe drugs
Uses: prevent stress related gastritis in critically ill patient
- tx/prevention of dyspepsia/heart burn OTC
Sucralfate
Pharm: slurry dosed 4 x daily via NG tube
Uses: prevent stress related gastritis
Misoprostol
PGEI analog
Pharm: oral tablets 4 x per day
Uses: prevent NSAID ulcers, expel aborted fetus (causes uterine contractions)
Side effects: diarrhea, abdominal cramps/ pain
Bismuth
Peptobismol
Pharm: antisecretory, antimicrobial effects
- antinflammatory effects of salicylic acid
Uses: dyspepsia, diarrhea
- included in 2nd line H pylori regimens
Metoclopramine/ droperidol
Pharm: D2 blockade plus weak serotonin antagonism
Mech: suppreses inhibitory dopamine effects on Ach release, increase GI contractions
Uses: increase stomach emptying in diabetic or post surgical gastric stasis
- treat GERD resistant to PPI/H2 therapy
- antiemetic
SIde effects: sedation, restlessness, anxiety, agitation, EPS, tardive dyskinesia
- droperidol for QT prolongation/sudden death
Erythromycin
macrolide antibiotic stimulates receptor for motilin
- off label for gastric stasis
Laxatives
Uses: prevent/treat constipation surgery, opioid constipation, GI disorders, evacuation of bowel
Contra: obstructive GI pathology
Mech: increase fluid content and decrease transit time
bisacodyl
Mech: act on enteric nerves to increase colon contractions and secretions, stimulant laxatives
Pharm: 6-10 hr oral, 30-60 rectal
Uses: combow ith stool softeners to treat opioid constipation or osmotic laxative PEG before bowel surgery/exams
castor oil
obsolete stimulant laxative - toxic, seldom used
Senna, cascara, aloes
6-12 hour orally., 2 hour rectally
- available OTC not safe or effective
Isotonic PEG electrolyte solutions
Osmotic laxatives
Mech: solutions of poorly absorbed solutes that retain water in GI tract
Pharm: 240 ml every 10 min
Uses: bowel cleansing before exams, smaller doses safe to prevent or treat constipation
Sodium phosphate laxatives
Pharm: fast acting, take with water to avoid electrolyte shifts
Contra: patients with renal and cardiac disease, electrolyte abnormalities
Uses: two dose regiment for bowel cleansing before exams
Magnesium hydroxide
milk of magnesium, magnesium citrate
Uses: acute constipation
Side effect: hypermagnesemia with chronic use in patients with renal insufficiency
lactulose, sorbitol, mannitol
Pharm: slow acting bacterial hydrolysis in lower GI tract
Side effect: flatulence, cramps
- lactulose can trap acid causing reduce blood ammonia in hepatic encephalopathy
bran, psyllium, methylcellulose, polycarbophil
bulk forming laxatives
Pharm: slow acting, absorb water, distend colon, promote peristalsis
docusate, glycerin, mineral oil
Stool softeners
Pharm: slow acting, surfactants that increase water and lipid content of stool
- oral or rectal dosing
Uses: docusate is commonly given to hospitalized patients to prevent formation of hard, irritating feces
- not acute relief of constipation
Lubiprostone
Chloride channel activator
Pharm: prostanoic acid analog
Mech: increases intestinal secretions
Uses: chronic constipation or IBS with constipation
loperamide
Pharm: opiate, meperidine analog with negligible CNS penetration
Uses: OTC antidiarrheal
Diphenoxylate
Pharm: opiate, meperidine analog with some CNS effects at high doses
octreotide
Mech: somatostatin analog that inhibits GI/pancreatic hormones and 5HT
- intestinal, pancreatic and bile secretions
- GI motility
Uses: dumping syndrome/diarrhea post gastric surgery, watery diarrhea, flushing of carcinoid tumors and VIPomas, decrease portal pressure and variceal bleeding with chronic liver disease
amitryptylline
TCA
Uses: abdominal pain in IBS (hyperalgesic state in nerves to regions of GI)
alosetran
Pharm: potent long acting 5HT3 antagonist
Uses: severe IBS with predominant diarrhea
Side effects: 10% constipation, serious fatal ischemic colitis, serious constipation
ondansetron, granisetron, dolasetron, palosetron
Pharm: 5HT3 antagonists, oral or IV dosing (palosetron only IV)
Uses: nausea and vomiting, combo with dexamethasone for chemo nausea
- with NK1 antagonist for severe delayed chemo nausea/vomiting
Side effect: no major drug interactions
dexamethasone
corticosteroid
Pharm: enhance effects of 5HT3 antagonists and other agents
Uses: combo therapy to prevent/treat chemo n/v
Side effects: steroid toxicity profile covered later in course
Aprepitant, fosaprepitant
Neurokinin 1 (NK1) antagonists
Pharm: antagonizes substance P in CNS
- enhances 5HT3 antagonists and other agents
Uses: combo with other agents for delayed chemo N/V
Side effects: safe, may inhibit metabolism of drugs by CYP3A4
prochlorperazine, chlorpromazine
phenothiazines
Pharm: weak D2 blocking effects
Uses: mild N/V, not 1st line agents for chemo N/V
Side effects: CNS adverse effects
cyclizine
H1 antagonist
- ineffective for CINV, useful for motion sickness prophylaxis
scopolamine
muscarinic antagonist
- ineffective for CINV useful for motion sickness prophylaxis
drobaninol
Weed
- 2nd line therapy when other agents are ineffective or poorly tolerated
pancrelipase
pancreatic extract containing lipase, amylase, proteolytic activity
Pharm: orally before meals
Uses: treat pancreatic enzyme insufficiency from CF, pancreatitis
ursodiol
Pharm: naturally occurring bile acid taken orally to dissolve small cholesterol gallstones
Uses: prevent gallstone formation during rapid weight loss in obese or treat chole gallstones
5 ASA (sulfasalazine, olsalazine, basalazide, mesalamine)
used for IBD to maintain remission in UC more than Crohn’s disease
- sulfasalazine obsolete
Azathioprine and mercaptopurine, methotrexate
Uses: anti-CA drugs interfere with nucleotide synthesis, inhibit cell proliferation and exert immunosuppressive effects
- lower doses in IBD
Uses: induce and maintain remission of UC and Crohn’s disease
Infliximad, adalimumba, certolizumab
TNF alpha antibodies
- immunosuppressive agents
natalizumab
anti integrin
- interferes with leukocyte adherence and migration through vascular endothelium
Side effects: fatal leukoencephalopathy by reactivating JC virus latent
