AMBOSS pharm gastric Flashcards
H2 antihistamines? 4
Ranitidine
Famotidine
Nizatidine
Cimetidine
Location of H2 receptors?
Gastric parietal cells (oxyntic cells) Vascular smooth muscle Neutrophils Central nervous system Heart Uterus
Histamine effects on H2 receptors? 3
Increased gastric acid secretion
Positive inotropism and enhanced automaticity
Smooth muscle relaxation leading to vasodilatation
H2 antihistamines. revers or nonrevers?
REVERSIBLE
H2 antihistamines. What G protein?
Gs protein-coupled receptor
H2 antihistamines. effect on cAMP?
↓ adenylyl cyclase activity → ↓ cAMP levels –> ↓ protein kinase A activity → ↓ phosphorylation and activation of H+/K+ ATPase → ↓ gastric acid (H+) secretion
what H2 antihistamine has most side effects?
cimetidine
cimetidine Antiandrogenic effect (via release of prolactin)?
erectile dysfunction, gynecomastia, low libido in men
Cimetidine on CYP450?
Inhibition of cytochrome P450 (CYP2C19) → various drugs interactions, e.g., clopidogrel
Cimetidine due to cross of BBB?
Headaches, dizziness, confusion due to its ability to cross the blood-brain barrier
Cimetidine cross what apart from BBB?
placenta (but is considered safe)
Cimetidine on kidney?
Reduces renal creatinine excretion (along with ranitidine)
when to take H2 antihistamine (daytime)?
H2 blockers need to be taken before dinner.
H2 antihistamine indications?
Anaphylactic shock (together with H1 antihistamines)
Symptomatic treatment of peptic ulcers: reduce the production of hydrochloric acid (less effective than PPIs )
Gastroesophageal reflux disease (GERD)
Gastritis
Zollinger-Ellison syndrome
Relative contraindications of H2 antihistamine?
Pregnancy, since cimetidine is known to cross the placental barrier
Nursing mothers
Children
Proton pump inhibitors. drugs?
Omeprazole Esomeprazole Pantoprazole Lansoprazole, dexlansoprazole Rabeprazole
Proton pump inhibitors. What drugs have the highest bioavailability and achieve the highest plasma levels?
Lansoprazole, dexlansoprazole
Proton pump inhibitors. Most gastro-specific drug?
Pantoprazole
Administration of PPI. Daytime?
1 Tablet/day taken in the morning on an empty stomach
PPI. Reverse or nonrevers inhibition?
irreversible inhibition of H+/K+ATPase in parietal cells → increases stomach pH
Degree of gastric acid supression by PPI?
Complete suppression of gastric acid secretion
why PPI best before meal?
PPIs are given in an inactive form, which is activated and takes effect in an acidic environment (e.g., the canaliculi of the apical parietal cells). The lower the pH level is, the higher the enrichment of PPIs in the parietal cells (high specificity of PPIs). The highest levels of H+/K+ ATPase enzyme activity are reached in the parietal cell after a period of prolonged fasting. Therefore, administering PPIs before the first meal of the day achieves highest efficacy.
PPI. GI complications?
……
↑ Risk of C. difficile infection
Reactive hypergastrinemia
↓ Absorption of iron and vitamin B12
↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
Nausea, diarrhea, abdominal pain, flatulence
PPI. GI complications?
Nausea, diarrhea, abdominal pain, flatulence
…..
Reactive hypergastrinemia
↓ Absorption of iron and vitamin B12
↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
↑ Risk of C. difficile infection
PPI. GI complications?
Nausea, diarrhea, abdominal pain, flatulence
↑ Risk of C. difficile infection
….
↓ Absorption of iron and vitamin B12
↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
Reactive hypergastrinemia
PPI. GI complications?
Nausea, diarrhea, abdominal pain, flatulence
↑ Risk of C. difficile infection
Reactive hypergastrinemia
….
↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
↓ Absorption of iron and vitamin B12
PPI. GI complications?
Nausea, diarrhea, abdominal pain, flatulence
↑ Risk of C. difficile infection
Reactive hypergastrinemia
↓ Absorption of iron and vitamin B12
…
↓ Absorption of calcium and magnesium → ↑ risk of osteoporosis in long-term use→ ↑ risk of fractures in elderly individuals
Why PPI cause decr Ca absorption?
Because the gastric environment becomes less acidic, dietary calcium remains bound to oxalate, resulting in reduced absorption in the duodenum and jejunum.
PPI neurological adverse?
Lightheadedness, headaches
Possibly increased risk of developing cognitive impairment/dementia
PPI renal?
in rare cases, acute interstitial nephritis
PPI on lungs?
↑ Risk of pneumonia;
Particularly in the 30 days after starting therapy; possibly due to aspiration of gastric content containing a larger number of bacteria than usual following suppression of gastric acid
PPI indications.
Peptic ulcer disease (gastric and duodenal ulcers)
Prevention of stress ulcers
!Gastroesophageal reflux disease
Gastritis
Combination treatment in Helicobacter pylori eradication therapy
Zollinger-Ellison syndrome (gastrinoma)
Gastropathy caused by NSAIDs
Special indication: MALT lymphoma (stages I and II)
PPI interactions enzyme?
CYP2C19-mediated
Omeprazole and esomeprazole interactions. Clopidogrel?
↓ activation
Omeprazole and esomeprazole interactions. Warfarin, phenprocoumon?
↓ clearance
Omeprazole and esomeprazole interactions. Phenytoin, carbamazepine?
↑ clearance
Omeprazole and esomeprazole interactions. Nifedipine?
↑ absorption, ↓ clearance
Omeprazole and esomeprazole interactions. Diazepam?
↓ clearance
