Histamine - 2 Receptor Antagonist (H2 Blockers)

20 mL of saline

H2 blocker IVP dose is diluted in what?

diarrhea, arthralgias, rash, thrombocytopenia, confusion, dizziness, MS pain, pachycardia, malaise, leukopenia, headache

11 AE of H2 blockers

-idine

all H2 blockers end in what?

active duodenal ulcers, benign gastric ulcers, hypersecretory conditions, GERD, erosive esophagitis, prevention of stress ulcers, upper GI bleed

seven uses for H2 blockers

renal

H2 blocker excretion

smoking

has been shown to decrease effectiveness of H2 blockers

activation of intracellular stimulatory protein G

how acid is formed - H2 receptor activation leads to what?

activation of membrane-bound ATPase pump

how acid is formed - activation of intracellular stimulatory protein G leads to what?

hydrogen being pumped out of oxyntic cells into stomach lumen

how acid is formed - activation of membrane bound ATPase pump leads to what?

hydrochloric acid

how acid is formed - hydrogen being pumped out of oxyntic cells into the stomach lumen leads to what?

Histamine 2 receptor activated

how acid is formed - initial step

H2 blockers

first choice of med for treating duodenal and gastric ulcers

displaces histamine for the H2-receptor preventing stimulation of acid secretion

H2 blocker MOA

hepatic

H2 blocker metabolism

low

H2 blocker protein binding

ranitidine (Zantac)

H2 blocker prototype

hepatic and renal patients

H2 blockers are cautioned in what two patients?

gastric and duodenal ulcers

H2 blockers are the 1st choice for treating what?

elderly, COPD, immunocompromised

H2 blockers contraindicated in what three patients due to the increased risk of pneumonia?

azole antifungals, digoxin

H2 blockers decrease the effect of what two drugs?

variable

H2 blockers first pass effect

slowly; prevent hypotension and cardiac arrythmias

H2 blockers given ___ to prevent ___ and ___.

require acidic GI environment for absorption

H2 blockers may inhibit the absorption of drugs that ___?

2 hours

H2 blockers should be staggered with antacid to allow ___ in between

alcohol, salicylates, warfarin, narcotics, CCB, caffeine, theophylline

H2 increases the effects of what seven drugs?

reversible

H2 receptor blockers have ___ inhibition

ranitidine (Zantac) cimetidine (Tagamet) famotidine (Pepsid) nizatidine (Axid)

four H2 blockers

black, tarry stools, bloody vomit, coffee ground emesis, sudden persistent stomach pain

four signs of GI bleed

continue to take, takes 4-6 weeks for ulcer to heal but less time for symptoms to go away

patient education - (H2 blocker) what does the patient do if symptoms disappear during drug therapy? why?

do not substitute prescription for OTC because different potencies

patient education - H2 OTC and prescribed

alcohol, caffeine, spicy foods and products containing aspirin or ibuphrophen and smoking

patient education - teach (5) all contribute to gastric irritation and should be avoided