GI Drugs Flashcards
How does Ranitidine work?
H2 receptor antagonist
blocks production of histamine, reducing gastric acid secretion
What can antacids, PPIs and H2 antagonists mask symptoms of?
Gastric cancer
How does Omeprazole work?
PPI
inhibits H+/K+ATP ase pumps on gastric parietal cells, completely blocking gastric acid secretion
Side effects of omeprazole?
prolonged treatment can lead to hypomagnesaemia, which can lead to arrhythmia
+ GI disturbances, headache
Indication and mechanism of Loperamide?
Anti-diarrhoeal/motility
CNS sparing opioid effects - mew receptors of myenteric plexus
decreases propulsive contractions, inhibits ACh release
Overall - slows bowel content, allowing for water absorption
Potential side effects of Loperamide?
constipation, cramping
risk of opioid toxicity if used with other opioid analgesics
Mechanism of action for Senna?
contact/irritant laxative
irritates bowel, increases smooth muscle activity
stimulates water and electrolyte secretion, increasing colonic volume
Side effects of Senna
Hypokalaemia
loss of colonic tone, pain, cramping
diarrhoea
Name 2 Aminosalicylates
Mesalazine, Sulfasalazine
How do Aminosalicylates work
Release 5-aminosalicylic acid - anti-inflammatory/ immunosuppressive effects
acts topically on the gut rather than systemically
Indications for Aminosalicylate use
Ulcerative colitis - gastro-resistant coating to delay to colon
Rheumatoid arthritis
Contra-indications for Aminosalicylate use
Aspirin hypersensitivity (are the same class of drug) Renal impairment - monitor 3 months prior, and after
Indication and mechanism of Metoclopramide
Antiemetic, D2 blocker - nausea
Aids gastric emptying, by blocking dopamine receptors in the medulla
relaxes stomach and LOS
Side effects of Metoclopramide
Diarrhoea
extrapyramidal syndromes - acute dystonic reaction, oculogyric crisis
interactions of metoclopramide
avoid dopaminergic PD agents
increased side effects with antipsychotics
