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
