Proton Pump Inhibitors
This enzyme pump on the parietal cell's luminal membrane is irreversibly inhibited by PPIs and is the final common pathway for acid secretion.
What is H⁺/K⁺ ATPase?
This suffix marks most H2 receptor antagonists, including cimetidine, ranitidine, famotidine, and nizatidine.
What is -tidine?
This antacid's overuse is associated with constipation, hypophosphatemia, osteodystrophy, proximal muscle weakness, and seizures.
What is aluminum hydroxide?
Bismuth and this other agent work by binding to the base of a gastric ulcer, physically protecting it so bicarbonate secretion can restore the pH gradient.
What is sucralfate?
Unlike H2 blockers, PPIs suppress both nocturnal acid secretion and this meal-related type, making them more effective overall.
What is meal-stimulated acid secretion?
Even on an H2 blocker, acid secretion can still occur through these two alternate mechanisms.
What are direct vagal stimulation of parietal cells and gastrin stimulation?
This antacid is linked to milk-alkali syndrome and a rebound rise in acid, since the hypercalcemia stimulates gastrin release.
What is calcium carbonate?
Patients on PPIs have a 2–3x increased risk of this spore-forming diarrheal infection, with older age as an added risk factor.
What is Clostridioides difficile colitis?
This drug class is first-line treatment for Zollinger-Ellison syndrome (gastrinoma).
What are proton pump inhibitors?
This H2 blocker potently inhibits cytochrome P-450, crosses the blood-brain barrier and placenta, and causes numerous drug interactions plus confusion.
What is cimetidine?
Antacids can change this property of other drugs by altering gastric and urinary pH, affecting absorption and excretion.
What is bioavailability?
Beyond C. diff, chronic acid suppression from PPIs also raises the risk of this respiratory infection.
What is pneumonia?
A patient on a PPI for 5 years now has osteoporosis with a hip fracture, and her doctor adds calcium supplements and starts bone density monitoring. Walk through the mechanistic link between her PPI and this new diagnosis.
What is reduced calcium absorption?
*suppressing gastric acid --> less acidic environment --> worse calcium absorption --> osteoporosis
Cimetidine's anti-androgenic effects can cause this triad in men.
What are gynecomastia, impotence, and hyperprolactinemia?
An infant with pathologic GERD and failure to thrive after feeds should get thickened feeds plus, cautiously, this drug class.
What are proton pump inhibitors?
A patient with Zollinger-Ellison syndrome is still hypersecreting acid despite maximum dose PPI therapy. What agent gets added, what class is it, and why does that class help when a PPI alone doesn't?
What is octreotide and somatostatin?
A cystic fibrosis patient on pancreatic enzyme replacement therapy still has steatorrhea. What drug should be she take and why does it help?
*enhances fat absorption by indirectly protecting lipase*
Both cimetidine and ranitidine decrease renal excretion of this substance, a side effect not shared by the other H2 blockers.
What is creatinine?
A patient chronically overusing one particular antacid develops hypercalcemia, metabolic alkalosis, and her acid reflux has gotten worse. Which antacid is she taking and what's the mechanism connecting her lab findings to worsening reflux?
What is calcium carbonate?
Milk-alkali syndrome
* hypercalcemia --> gastrin release --> rebound acid hypersecretion *
In a patient on H. pylori bismuth quadruple therapy, what distinct job is bismuth doing at the ulcer site?
Binds directly to the base of the ulcer and physically shields it --> allows local bicarbonate secretion to reestablish the mucosal pH gradient at the injury site.