Treatment of GERD

Question 1

Pathways regulating gastric acid secretion

Answer 1

Ach release in the stomach that stimulate the H/K ATPase

Acts on ECL cell..this produces histamine which acts on H2…this helps activate the other receptors…H+ produced into stomach

Question 2

Prostaglandins

Answer 2

Have a cytoprotective effect due to neutralization of the H+…essentially block the Histamine receptor from acting

Question 3

Gastric antacids

Answer 3

Calcium carb - may cause belching

MgOH - is most common

Question 4

Histamine formation

Answer 4

From histidine using histidine decarboxylase

Question 5

Antihistamines - 1st gen

Answer 5

Diphenhydramine - benadryl is prototpype

Inverse agonist of H1 receptor

Works best if administered prior to histamine release…

SE - crosses BBB so causes sedation and anti-musc propertieis

Question 6

2nd gen antihistamines

Answer 6

Cetirizine - H1 blocker with no penetration of BBB so sedation limitd

Question 7

Hisatmne receptor pharmacology

Answer 7

H1 - nonvascular smooth muscle and inc DAG/IP3…inc vascular perm, inc vasodilation and constrict nonvasc smooth muscel

In gastric - H2….inc cAMP and leads to vasodilation and gastric acid production and cardiac stim

Question 8

H2 receptor antihistamines

Answer 8

Cimetidine and ranitidine

Effective against basal acid and nocturnal secretion…good bc nocturnal secretion is primary factor in duodenal ulcer healing

NMech - competitive and reversible inhibitor of the H2 receptors

Question 9

NAB

Answer 9

Presence of 60 min of pH under 4 bt 10 and 6 for pts taking a PPI twice daily before meals

H2 antihistamines can be given to suppress

Question 10

H2 antihistamines

PKs and SE

Answer 10

Absorbed very fast

Rare SE

Cimetidine inhibits P450 mediated metabolism in the liver

Question 11

Omprazole

Answer 11

Irreversible inhib of the H/K ATPase

Question 12

OMperazole and pantoprazole

Answer 12

Omeprazole - older

PPIs are primary tx for and kind of ulcers and can be used for H pylori as a combo therapy

Esomeprazole is only the S isomer

Question 13

Mech of omprazole and pantoprazole

Answer 13

Travle through the BS to parietal cells and accumulate in the acidic secretory canalicul where thye form covalent bonds iwht cysteine reisdues of the H/K proton pump

Question 14

Omp and panto uptake and activation

Answer 14

Unstable at a low pH so omep is given in an alkali soluble capsule

Reuqire acidic enviornemtn to become actives so given with food to stimulate acid secretion

should NOT be given withH2 antags or antacids because those dec acid production

Question 15

Omep and patno PKs

Answer 15

Extensively metabolized by p450s and binds irreversibly

Question 16

Typicl course of tx

Answer 16

PPIs given for 8 weeks and then discontinued or maintained long term at low dose

Imep - profound hypochlorhydria and significant hypergastremia

Gastric bacterial overhorwth can also occur

Question 17

Side effects of PPI

Answer 17

Inc pH can alter uptake of azoles

Omep can inhibit drug metab enzymes

Question 18

Bismuth and sucralfate

Answer 18

Mismuth - promotes healing but does NOT neutralize gastric acid

Sucra - AlOh and sulfated sucruse that forms visvous suspension that binds and protects mucosa…NOT antacid and promotes PG synthesis

Question 19

Klling H/pylori with ABs

Answer 19

Use metro and clarithro with amox as alt

14 days

Also give a PPI