PUD, H. Pylori and Antiflatulants Flashcards
What are the causes of PUD?
- heliCobacter pylori bacteria - 95% 2. benign pancreatic tumour secretions - less than 5%
Describe what helicobacter pylori bacteria do in the stomach?
attach to the epithelial cellsof the stomac and duodenum which stops them from bein washed out of the stomach and once attached cause damage to the cells by secreting degradative enzymes, toxins and initiating a self destructive immune response
State treatments for PUD?
- antacids 2. H2 receptor blockers 3. mucosal protective agents 4. proton pump inhibitors 5. anti-cholinergics 6. prostaglandin analogs 7. anti-microbial agents
State examples of antacids?
weak bases - 1. aluminium hydroxide - Al(OH)3 2. magnesium hydroxide - Mg(OH)2 3. calcium carbonate - CaCO3 4. sodium carbonic acid - NaHCO3
What are the actions of antacids?
- prevent injury from H+ 2. neutralize gastric acid → reduce gastric acidity→ reduce peptic activity 3. protect face of ulcer
Side effects?
- contraindicated in patients with impaired renal function 2. Mg salts → diarrhea 3. aluminium salts → constipation 4. calcium carbonate → tastes chalky + frequent use causes constipation
What is the function of histamine H2 receptor blockers?
Inhibit secretion of gastric acid through competitive inhibition of Histamine H2 receptors - Suppresses 24 hour gastric secretion by 70%
What is the down side of H2 receptor blockers?
may alter the effects of other drugs through interactions with CYP450 - especially cimetidine
State examples of H2 receptor blockers?
- cimitidine 2. famotidine 3. ranitidine 4. nizatidine
What are the general side effects?
- diarrhoea 2. dizziness 3. muscle pain 4. alopecia 5. hypergastrinaemia
What are the specific side effects of cimetidine?
- inhibits metabolism of estrogen 2. crosses placental barrier and appears in breast milk 3. long term use in females may cause galactorrhea 4. long term use in males may cause gynecomastia and impotence
Which drugs undergo first pass hepatic metabolism?
- cimetidine 2. ranitidine 3. famotidine
Which drug has little first pass metabolism?
nizatidine
What is the duration of action?
6–10 hours : given twice daily
How do they work?
Inhibit 90% of nocturnal acid (which depends largely on histamine).
Give examples of proton pump inhibitors?
- omeprazole 2. iansoprazole 3. pantoprazole
What are the actions of proton pumps?
Strong inhibitors of gastric acid secretion through irreversible inhibition of proton pump, preventing “pumping” or release of gastric acid - Decreases acid secretion by up to 95% for up to 48 hours
What is the duration of action?
48-72 hours
What is the duration of the course of treatment?
4-8 weeks
Compare proton pump inhibitors and H2 receptor blockers?
proton pump inhibitors have faster relief and healing than H2 receptor blockers
What are the gastrointestinal side effects?
nausea, vomiting, diarrhea, abdominal pain
What are the nervous system side effects?
headache, somnolence, peripheral neuritis, confusion
Describe other general side effects?
- overgrowth of bacteria - increases in gastric bacterial concentrations 2. impotence, gynaecomastia, pain in muscles and joints
Describe the drug interactions of PPIs?
- May affect absorption of drugs due to decreased gastric acidity like digoxin and ketoconazole 2. Omeprazole can inhibit metabolism of coumadin (Warfarin ), diazepam and phenytoin
Which drugs have no significant interactions?
Rabeprazole and pantoprazole
What do prostaglandins exist as?
PGE2 + PG12 analogues
When are they used?
For treatment of NSAID induced injury
How do they work?
- Stimulates Gi pathway, leading to decrease in gastric acid release 2. Stimulate secretion of mucus and bicarbonate (cytoprotective effect)
What are the side effects?
- diarrhea 2. cramping 3. abdominal pain (30%) 4. birth defects 5. premature birth
State an example of a prostaglandin?
misoprostol
What are anticholinergics?
muscarinic M1 acetylcholine receptor antagonist
How do they work?
block gastric secretions - about as effective as H2 blockers
What are the side effects?
anorexia, blurry vision, constipation, dry mouth, sedation
Give examples?
- pirenzipine 2. atropine
Give an example of a gastrin-receptor antagonists?
proglumide
Name mucosal protective agents?
sucralfate (carafate)
Describe the mode of action of sucralfate?
- Breaks down into sucrose sulfate and an aluminum salt in the stomach 2. Negatively charged sucrose sulfate binds to positively charged proteins in the base of ulcers or erosion, forming a physical barrier 3. Physical barrier restricts further caustic damage and stimulates mucosal prostaglandin and bicarbonate
Describe the drug interactions?
May bind with other drugs and interfere with absorption
Describe the treatment?
- taken on an empty stomach before meals 2. Given approximately 2 hours before or after other drugs
Name colloidal bismuth compounds?
- bismuth subsalicylate 2. bismuth subcitrate - Bismuth is minimally absorbed from GIT (< 1%).
Describe the action of bismuth?
- Coats ulcers and erosions, creating a protective layer against acid and pepsin 2. It may stimulate prostaglandin, mucus, and bicarbonate secretion
Describe the benefit of bismuth?
has direct antimicrobial effects and binds enterotoxins, accounting for its benefit in preventing and treating traveler’s diarrhea
What is bismuth used as?
Used as second-line therapy for the eradication of H pylori infection - a PPI with bismuth subsalicylate , tetracycline and metronidazole for 10–14 days
What are the side effects?
blackening of stool and tongue
What are antimicrobial agents used for?
> 85% PUD caused by H. pylori
Describe the antibiotic ulcer therapy?
- Bismuth - Disrupts bacterial cell wall 2. Clarithromycin - Inhibits protein synthesis 3. Amoxicillin - Disrupts cell wall 4. Tetracycline - Inhibits protein synthesis 5. Metronidazole - Used often due to bacterial resistance to amoxicillin and tetracycline, or due to intolerance
What is the use of antiflatulants?
used to relieve panful symptoms associated with gas
Give an example of an antiflatulant?
simethicone - a detergent
Describe the action of simethicone?
- Alters elasticity of mucus-coated bubbles, causing them to break 2. Large bubbles -> smaller bubbles, and less pain - Used often, but limited data regarding effectiveness
