Exam 3-Antihistamines and Gastric Acid

Question 1

mast cell localization

Answer 1

nose, mouth, feet, internal body surfaces, vessel walls and GI mucosa. functions as a NT, controls gastric acid secretion

Question 2

H1 histamine receptor

Answer 2

on vascular endothelium. causes vasodilation and capillary permiability. on non vasc smooth muscle causes contraction and on nerves and neurons causes pain/itch. signal pathway Gq to PLC to increase Ca. antagonist good for runny nose and pain/itch

Question 3

H2 histamine receptor

Answer 3

found on gastric mucosa (acid sec), sm muscle (relax), cardiac muscle (stim), mast cells (autoreceptor). Signals Gs to increase Ac and increase cAMP, antagonist used for heartburn and ulcers

Question 4

physiological effects of cromolyn and nedocromil

Answer 4

decrease histamine release. stabilize mast cells

Question 5

H1 antagonists do what

Answer 5

decrease runny nose, cold and itch

Question 6

H2 antagonists do what

Answer 6

decrease gastric acid

Question 7

1st gen H1 antagonists

Answer 7

readily cross BBB. less selective, autonomic alpha and M blockade, produce sedation, greater range of uses.

Question 8

2nd and 3rd gen of H1 antagonists

Answer 8

do not cross BBB. more selective. little autonomic blockade, less sedation/CNS effects, only for rhinitis or urticaria

Question 9

Uses of 1st gen H1 antagonists

Answer 9

allergic rhinitis, cold, itch, derm (H1)
motion sickness, vertigo (Muscarinic receptors)
insomnia (alpha receptors).
SE: sedation, ortho hypotn, GI, dry mouth, urinary retention
interact:depressants, inducers
caution: depression

Question 10

Ethanolamines:carbinoxamine, clemastine, diphenhydramine, dimenhydrinate

Answer 10

1st gen H1 antagonists

Question 11

Ethylendiamines: pyrilamine, tripelennamine

Answer 11

1st gen H1 antagonists

Question 12

Alkylamines: brompheniramine, chlorpheniramine, tripolidine, acrivastine

Answer 12

1st gen H1 antagonists

Question 13

phenothiazines: promethazine

Answer 13

1st gen H1 antagonists

Question 14

Piperazines: hydroxyzine, cyclizine, meclizine

Answer 14

1st gen H1 antagonists

Question 15

Piperidines: cyproheptadine, phenindamine

Answer 15

1st gen H1 anagonists

Question 16

2nd gen H1 antagonists:certirizine, levocertirizine, fexofenadine, loratadine, desloratadine

Answer 16

for allergic rhinitis, urticaria. metabolites of loratadine are active.
MOA: antagonize H1 receptors
SE: GI
Interact: inducers of liver enz

Question 17

3rd gen histamine blockers: azelastine, olopatadine, alcaftadine, ketotifen, pemirolast, lodoxamide

Answer 17

for allergic rhinitis and or conjunctivitis.
MOA: antagonism of H1 and mast cell stabilization.
SE: bitter taste, mild sedation
Interact: sedatives

Question 18

H2 antagonists: cimetidine, ranitidine, famotidine, nizatidine

Answer 18

for GERD, ulcers and hypersecretory dx.
MOA: reversible antagonism of H2 receptors.
SE: cimetidine-inhibits p450 enz (causes antisteroidal effects) like gynecomastia
interact: absorp of drugs, famotidine may inhibit etoh metabolism

Question 19

metoclopramide for gastric acid

Answer 19

D2 antagonist. accelerates gastric emptying

Question 20

Muscarinic antagonists for gastric acid

Answer 20

hyoscyamine and methoscopolamine

Question 21

secretin for gastric acid

Answer 21

enteric peptide hormone. only inj

Question 22

PPIs: azoles

Answer 22

for GERD, ulcers and hypersecretory dx. omeprazole-only S is active isomer. they are all suicide inhibitors so have long DOA.
SE: Gi, c diff*** hypomag
Interact: omeprazole and lansoprazole inhibit p4502c19

Question 23

bismuth subsalicylate (pepto)

Answer 23

for gastroprotection, eradicate hpylori. MOA:salts chelate with proteins and collect in ulcer base.
Interact: acid reducer***
reduces bioavail of tetracycline.
contraind: kids

Question 24

treatment for H pylori ulcers

Answer 24

PPI with clarithromycin and amoxicillin or flagyl. OR PPI with bismuth, tetracycline or flagyl.

Question 25

Helidac

Answer 25

bismuth, flagyl and tetracycline

Question 26

Sucralfate

Answer 26

for treatment or prophylaxis of ulcers. MOA: inhibit pepsin hydrolysis of mucus, forms layer, stim PG production. SE: constipation, Al OD. Interact: acid reducers*** many PO drugs-get stuck and they are elim quickly

Question 27

These two drugs need to work at low pH and cannot be given with antacids

Answer 27

sucralfate and pepto

Question 28

antacids

Answer 28

for GERD. MOA: metal and HCL make metal-Cl and water+ CO2. Simethicone works as a surfactant. SE: CO2 may cause gas, Al-constipate, Mg-diarrhea, CaCO3 rebound high H-abdominal distention and burping. interact:chelated by some drugs