Drugs for peptic ulcer Flashcards
types and sites of peptic ulcer
stomach (gastric ulcer)- due to decrease mucosal resistance
duodenum (duodenal ulcer)- due to ^ in gastric acid formation & secretion.
mechanism of acid (HCL) secretion?
muscarinic receptor-M3
histamine H3
gastrin G receptors
stimulate the proton pump to secret h ions into the gastric lumen, leading to formation of HCL
proton pump is the final common step of all pathways of HCL production from parietal cells, true or false?
true
factors protecting the gastric mucosa
- PGE2- inhibits acid secretion
- mucus
- innate resistance of mucosal cells
- bicarbonate secretion
- local NO
factors increasing acid secretion?
- DRUGS: NSAIDs, tobacco, alcohol
- FOODS: acidic drinks, fried foods, high protein diet
- EMOTIONS: anxiety, anger, stress
- H.PYLORI
- BILE from gall bladder
goal of ulcer therapy?
relief the pain
ulcer healing
prevention of complication
prevention of relapse
classes of anti-ulcer drugs?
- drugs reducing HCL secretion
- drugs neutralizing HCL
- ulcer protective drugs
- anti H pylori drugs
drugs reducing gastric acid secretion
H2 blockers: 1st line drugs (ranitidine, famotidine,roxatidine)
- proton pump inhibitors:1st line drugs (prazole`s)
- anticholinergics: pirenzepine
- PGE2: MISOPROSTOL
neutralization of gastric acid (antacids)?
- systemic antacids- not prefers because they are absorbed and body ph is disturbed (metabolic alkalosis) e.g sodium bicarbonate, sodium citrates
- local antacids: includes a combination of aluminum & magnesium salts
i. magnesium hydroxide & aluminium hydroxide
ii. magnesium triplicate & aluminum hydroxide.
antacids are no longer preferred for peptic ulcer treatment, that are used for ulcer pain relief and acidity (heart burn)
why is Al & Mg combination preffered?
because fast MgOH and slow AlOH yields prompted as well as sustained relief.
Mg are laxative while Al are constipating; these effects are nullified
gastric emptying is least affected
dose of individual component is reduced
side effects are neutralized
ulcer protectives?
SUCRALFATE: aluminium salt of sulfated sucrose: get converted into a jelly and covers the ulcer surface
works only in acidic PH<4
antacids decreases the effectiveness; should not be used with sucralfate
second line drugs: not preffered
anti H pylori drugs?
amoxicillin clarithromycin metronidazole/tinidiazole omeprazole bismuth sub citrate
h.pylori is gram negative bacilli
has high urease activity
produces ammonia
causses gastritis, dyspepsia,peptic ulcer, gastric lymphoma, g. carcinoma.
if there is absence of h.pylori testing and conventional therapy fails treat as for h.pylori-induced peptic ulcer
MDT (multi drug therapy) is used because resistance may develop for a single drug
acid suppression by ppi/h2 blockers + treatment effectiveness for h.pylori
anti h pylori therapy.. main regimens
2 or 3 drugs for 1 or 2 weeks
- US-FDA regimen: lansoprazole30mg + amoxicillin 1000mg + clarithromycin 500mg twice daily for 2 weeks
- british national formulary
H2 blockers
ranitidine
uses: zollinger ellison syndrome
gastro-esophageal reflux disease (GERD)
adverse effect: rapid i.v injection-bradycardia, arrhythmia, cardiac arrest.
ppi
omeprazole
uses: bleeding peptic ulcer, stress ulcer, GERD, zollinger ellison , preanesthetic medication-prevent aspiration pneumonia in unconscious patient
ADR: nausea,diarrheoa,pain abdomen, muscle/joint pain, rashes, leukopenia, hepatic dys
