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16 Cards in this Set
- Front
- Back
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What are the key parts of the stomach?
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Lower esophageal sphincter
Fundus Body Antrum Pyloric sphincter |
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What are the cells of the fundus and body?
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GASTRIC PIT
mucus secreting epithelial cells Mucus neck cells Parietal cells (--> HCl) Cheif cells (--> pepsinogen) Enterochromaffin-like cell D cells Mucosal mast cells |
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What is the aetiology of peptic ulceration?
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Excess acid & pepsin
- increased parietal cells, histamine, vagal activity, gastrin release. Imparied gastrin inactivation. Decreased somatostatin. Decreased mucosal resistance - atrophic mucosa, decreased mucosal blood flow (NO), decreased PGs, mucuos emusifiers Infection - Helicobacter pylori |
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Describe use of antimuscarinics for peptic ulcers.
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Rarely used as significan SEs e.g. constipation, dry mouth, blurred vision, urinary retension, gastric stasis and skin rashes
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Describe use of gastrin antagonists for peptic ulcers.
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Rarely used as poor effectiveness
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Describe use of somatostatin analogues for peptic ulcers.
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Requires parenteral administration
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Describe use of antacids for peptic ulcers.
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Non systemic and Systemic
Al salts - constipation; P & F depletion; interfere iwht absorption of some drugs & excretion of others Magnesium salts - diarrhoea; hypermagnesaemia in renal disease Sodium salts - promote fluid retention and alkalosis; milk-alkali syndrome Calcium salts - constipation/diarrhoea; milk-alkali syndrome; hypercalcaemia eventually leading to renal calculi Even with non-systemic effect short lived |
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Describe use of CARBENOXELONE for peptic ulcers.
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From liquorice root
- appears to accelerate the healing of gastric ulcers - significant side effects. Carbenoxelone and related compounds have a "mineralcorticoid" effect causing sodium and water retention which can lead to alkalosis, hypertension and hypokalaemia. It can precipitate glaucoma and urinary retention. |
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Describe use of SUCRALFATE for peptic ulcers.
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- Basic aluminium salt of sulphated sucrose
- Viscous at acid pH and adheres to surface of ulcers, to act as a barrier to the aggressive luminal factors (acid, pepsin, bile salts) - Antacids & meals should not be taken within half and hour of sucralfate as they may raise the gastric pH and alter the physicochemcial properties of sulcralfate - SEs include constipation, interference with absorption of some drugs or long term Al toxicity effecting CNS, bone and kidneys. |
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Describe use of BISMUTH COMPOUNDS for peptic ulcers.
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- Forms precipitate which binds to proteins on surface of ulcers at acidic pH providing barrier to aggressive factors in gastric juice.
- Batericidal to Helicobacter pyloris - SEs - Ammoniacal odour & taste and causes black discoloration of the tongue and faeces, long term could damage kidneys and CNS - Not to be taken with meals, antacids or other medication. |
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Describe use of PROSTABLANDIN ANALOGUES for peptic ulcers.
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- Inhibit acid secretion, increase mucosal blood flow & mucus, cytoprotective on gastric mucosa
- Misoprostol, Enprostil, arbaprostil, iloprostil, rioprostil and trimoprostil - Comparable ulcer healing efficacy with H2 receptor antagonists - Only in patients using NSAIDs with high risk of ulcer - SEs - pain endings sensitised so pain often worsens initially; diarrhoea, nausea, headache and dizziness; because of their tropic effects on the uterus (menorrhagia & dysmenorrhoea), prostaglandins are contraindicated in females of childbearing age. |
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Describe use of antibiotics for peptic ulcers.
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Helicobacter pylori unfortunately develops resistance very easily so need combination therapy e.g.
- Bismuth + Metronidazole + tetracycline or amoxycillin - Omeprazole + amoxycillin |
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Describe use of H2 Histamine antagonists for peptic ulcers.
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Cimetidine, Ranitidine, famotidine, nizatidine
Very low incidence of reversible SEs - headache, dizziness, skin rash, nausea, diarrhoea, confusion in elderly patients, impotence and gynaecomastia, Interferes with hepatic metabolism of certain drugs - Absorbed orally (decreased absorption if taken with antacids) - renally excreted - take care in renal failure |
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Describe use of proton pump inhibitors for peptic ulcers.
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Omeprazole, lansoprazole, pantoprazole, rabiprazol
- Completely block acid secretion by inactivating the hydrogen-potassium ATPase proton pump at the parietal cell surface - Extremely potent & rapidly effective (99.9%) - poor & variable bioavailability (increased bioavailability as decreased acid in stomach) - metabolized in liver - SEs interstitial nephritis, (nausea & diarrhoea), ? hypergastrinaemia and gastric mucosal changes. |
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What are some drugs that promote reflux?
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Anticholinergics
Phosphodiesterase inhibitors Nitrites Calcium channel blockers Dopamine agonists patient factors also important |
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What are some drugs to treat reflux oesophagitis?
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Antacids
Adjuncts with antacies - alginic acid, simethicone H2 histamine blockers metoclopramide/domperidone sucralfate cisapride proton pump inhibitors |
