Lectures 61/62 Flashcards
GI Protectant (Hockerman)
sodium bicarbonate - NaHCO3
systemically absorbed
neutralizing capacity - High
AE - systemic alkalosis, fluid retention, excess CO2 gas
commercially - in alka-seltzer with ASA
calcium carbonate - CaCO3
systemically absorbed
neutralizing capacity - moderate
AE - hypercalcemia, nephrolithiasis, milk-alkali syndrome CO2
commercially - tums and in rolaids with magnesium hydroxide
aluminum hydroxide - Al(OH)3
minimally absorbed
neutralizing capacity - high
AE - constipation, hypophosphatemia, if absorbed encephalopathy
commercially - AlternaGEL, in Maalox/Mylanta with magnesium hydroxide
Magnesium hydroxide - Mg(OH)2
minimally absorbed
neutralizing capacity - high
AE - diarrhea, if absorbed CNS toxicity
commercially - in Maalox/Mylanta with alumnium hydroxide and in Rolaids with calcium carbonate
PPI mechanism
irreversibly inhibit the proton pump to prevent H+ from leaving the parietal and combing with Cl- to form acidic HCl
prodrugs
PPI DRUGS
esomeprazole (nexium)
omeprazole (prilosec)
lansoprazole (prevacid)
rabeprazole (aciphex)
pantoprazole (protonix)
dexlansoprazole (dexilant)
vonoprazan
not a prodrug
potassium-competitive acid blocker (P-CAB)
recently approved in the US
sucralfate mechanism
polymerizes and forms protective barrier at ulcer site
acidic pH activates complex
misoprostol (cytotec) mechanism
reduced acid secretion of the parietal cells
has cytoprotective effects of enhanced mucus and bicarbonate secretion
semi-synthetic PGE1 derivative
used in combo with chronic NSAIDs
BSS mechanism
converted to bismuth salts and salicylic acid in the GI tract with antibacterial, antiviral, and antisecretory activity
rationale for antibiotic treatment of ulcers
many peptic ulcers are associated with infection of gastric mucosa by the gram negative bacili, H Pylori
combination therapy for antibiotic treatment of ulcers
- BSS
- some antibiotic - metronidazole, tetracycline, amoxicillin, clarithromycin
- H2RA or PPI
laxative classes
bulk and osmotic laxatives
stool softeners
secretory/stimulant laxatives
bulk and osmotic laxatives
psyllium (metamucil), methylcellulose (citrucel), calcium polycarbophil (FiberCon), PEG 3350 (Miralax), or Macrogol/Movicol
mechanism - increase water in the intestinal lumen via non-absorable sugars by osmotic force leading to distention and an increase in peristalsis
stool softeners
examples - docusate sodium (colace), mineral oil, glycerin, surfactants, and lubricants
mechanism - incorporate into stool to make passage easier and decrease water absorption; lubricate lower bowel to reduce fecal impaction; can decrease absorption of fat soluble vitamins
secretory/stimulant laxatives
examples - castor oil, bisacodyl, duloclax, cascara, senna, and aloes
mechanism - poorly known; irritation of the mucosa affects fluid secretion/absorption balance and induces peristalsis
5HT4 receptor agonists
Prucalopride (Motegrity) and Tegaserod (Zelnorm)
serotonin receptor, GPCR, GaS coupled, activation leads to increased cAMP, PKA activation, and release of ACh
Prucalopride (Motegrity) uses
chronic idiopathic constipation in adults
Tegaserod (Zelnorm) uses
IBS with constipation in women under 65yo
Tenapanor
sodium hydrogen exchanger (NHE3) inhibition to prevent the absorption of sodium from the luminal contents
prokinetic drugs
prucalopride
tegaserod
tenapanor
bethanechol
erythromycin
metoclopramide
neostigmine
Cl channel activators
Opioid receptor antagonists
metoclopramide (reglan)
D2 dopamine receptor antagonist
blockade of D2 receptors in the myenteric plexus leads to increase ACh release and produces anti-emetic effects
USES - promotes gastric emptying to facilitate small bowel intubation, post op and diabetic gastroparesis, and GERD
chloride channel activator drugs
lubiprostone (amitiza)
plecanatide (trulance)
linaclotide (linzess)
lubiprostone (amitiza)
stimulation of type 2 chloride channel (CIC-2)
increases chloride rich fluid secretion into the intestine
USES - IBS with constipation
