PUD Flashcards
Indications of Antacid therapy
Mild GORD
Dyspepsia
Reflux oseophagitis
MOA of Antacids
Neutralise gastric acidity
Which are the Antacids
NaHCO3
CaCO3
Al(OH)3
Mg(OH)3
AE of systemic antacids
NaHCO3:
Na and H2O retention=Hypertension
AE of Non-systemic antacids
CaCO3:
Hypercalcaemia, rebound acidosis, belching
Al(OH)3: Constipation
Mg(OH)3: diarhoea
In renal insufficiency, systemic antacids result in
Metabolic alkalosis
In renal insufficiency, non-systemic antacids result in
Toxicity
Caution in Mg(OH)3
renal insufficiency: incr. plasma Mg–>
hypermagnesaemia= mental depression, coma and NV
Caution in Al(OH)3
renal insufficiency: incr. Al–> CNS accumulation=incr. neurotoxicity, encephalopathy
DI in Antacids
Absorb other drugs: digoxin, phenytoin
Chelates other drugs: iron, tetracyclines
Incr. gastric emptying: decr. absorption of digoxin, levadopa
Incr. gastric pH: decr. absorp. of acidic drugs indomethacin, sulphonamides, ketoconazole, itraconazole
Urine alkalinisation: incr. clearance ot tetracyclines, sulphonylureas
Dosing interval requirements in Antacids
4 hrs before or 2 hrs after other drugs
Which are the PPIs
Omeprazole
Esomeprazole
Lansoprazole
Pantoprazole
Rabeprazole
Indications of PPIs
Duodenal & gastric ulcer (stress/NSAID)
GORD
H. Pylori irradication (+ antibiotics)
ZOllinger-Ellison Syndrome
MOA of PPIs
-Irreversibly bind to and inhibit H/K ATPAse pump enzyme of gastric parietal cell
-weak bases=incr. pH=stabilise ulcer clot= decr. bleeding
-inhibit H.pylore urease= prevent ammonia production and expose H.Pylori to acidic conditions
-inhibit gastric mucosal carbonic anhydrase
DOA of PPIs
24-48 hrs
Bioavailability of PPIs
Pantoprazole>lansoprazole>rabeprazole> omeprazole
DI of PPIs
inhibit CYP450:
decr. elimination of diazepam, warfarin, phenytoin
decr. gastric acidity:
decr. absorp. of ketoconazole, itraconazole
CI of PPIs
Lactation
Pregnancy 1st trimester
AE of PPIs
Diarhoea
NV
Flatulence
Headache
Vertigo
Abd. pain or colic
Which of the PPIs is partial reversible
Rabeprazole
Which are the H2 R antagonists
Cimetidine
Ranitidine
Indications of H2 R antagonists
PUD
Prevention of stress ulcer in critically ill patients
GORD
Zollinger Ellison syndrome
MOA of H2 R antagonists
Block histamine actions on H2 R in parietal cells
decr. ACh and gastrin-induced gastric acid secretion
What is Cimetidine
Is a potent CYP450 inhibitor
DI of Cimetidine
agents metabolised by CYP450:
midazolam
diazepam
Propranolol
Nifedipine
Phenytoin
=decr. gastric acidity: decr. absorp. of ketoconazole, itraconazole
AE of H2 R antagonist
diarhoea
NV
Myalgia
Pruritus
Skin rash
Gynecomastia
Name the prostaglandin
Misoprostol
What is Misoprostol
PGE1 analogue (a gastric cytoprotective agent)
Indications of MIsoprostol
prevent NSAID induced gastric and duodenal ulceration
MOA of Misoprostol in Cytoprotection
Cytoprotection:
Incr. bicarbonate secretion,mucus production, mucosal blood flow
= incr. O2 and nutrient supply to healing mucosa
=incr. epithelialisation
MOA of Misoprostol as in Acid-inhibition
decr. gastric cAMP levels
=decr. H/K ATPase pump activity
=decr. acid production
Caution in Misoprostol
Renal impairement
CI of Misoprostol
Pregnancy (tetrogenic)
Lactation
Paediatrics
AE of Misoprostol
Abd. pain
Diarrhoea
Menstrual disorders
Cramps
Uterine contractions
Vaginal Haemorrhage
Menorrhagia
Dysmenorrhoea
Which other drugs are used in PUD and GORD?
Sucralfate
Bismuth Subcitrate
What is Sucralfate
Its a sucrose-hydrogen sulphate aluminum complex
Its a mucosal protective agent
MOA of Sucralfate
In acidic pH<4: dissociates to ALOH and scurose octasulfate
Sucrose Octasulfate undergoes polymerisation= forms a viscous paste like complex with a strong -ive charge= binds +ively charged proteins in base of ulcers or erosions
Formed insoluble complex creates a barrier that protects ulcer from further damage for up to 6 hrs
Indications of Sucralfate
PUD
Refluc Oesophagitis
Chronic Gastritis
COMT??
DI of Sucralfate
Sulfate= decr. abs. of digoxin, phenytoin, cimetidine, ranitidine, warfarin, theophylline
AE of Sucralfate
Constipation
MOA of Bismuth Subcitrate
- absorbs toxins and coats ulcers and erosions–> creates a protective layer against acid
-stimulates PG, mucus, and bicarbonate secretion
Indications of Bismuth Subcitrate
PUD
Adjuct H.pylori assoc. gastritis therapy
AE of Bismuth Subcitrate
Teeth and stool darkening
Abd. pain
Metallic taste
