Gi Flashcards
Gaviscon
Alginate and antacid, buffers stomach acid and increases stomach content viscosity and reduces reflux
S/E antacids and alginates
Mg causes D and Aluminium causes constipation
Lansoprazole and omeprazole
PPI- irreversibly inhibit H/K ATPase in parietal cells. Final stage so significant reduction in acid secretion
S/E PPI
Mask symptoms of gastro oesophageal cancer. Fracture risk. Also O is a CYP inhibitor
Ranitidine
H2 receptor antagonist so less proton pump activation. Only partial
S/E H2 antagonist
Mask symptoms of cancer. Renal impairment. Not to use with antivirals as reduce exposure. ? carcinogenic contaminant
Mesalazine and used to treat
Aminosalicylate- release of 5 aminosalicylic acid.Treat ulcerative colitis
S/E aminosalicylate
Gi upset
What drugs are of concern when prescribing PPI
Phenytoin, warfarin and clopidogrel as CYP issues
Why do PPI give greater protection that H2 antag
Bind to end of pathway.
Agents that work of vestibular nucleus
Muscarinic receptor antagonist and H1 receptor antagonists
Hyoscine hydrobromide
Muscarinic receptor antagonist- block muscarinic ACh receptors in CTZ and vestibular nucleus
S/E muscarinic antagonist
Sedation, memory issues, glaucoma, constipation
Cyclizine
H1 receptor antagonist- good for motion sickness. Not for kids and old as confusion
Agents that work on visceral afferents in gut
5HT3 receptor antagonist and D2 receptor antagonist
What is 5HT
Serotonin
Ondansetron
5HT3 receptor antagonist- reduced mobility and GI secretions and centrally inhibits CTZ
Metoclopramide
D2 receptor antagonist- Increases ACh at receptors in gut. Promotes gastric emptying. Increases peristalsis
What is metoclopramide good for
Gout and illeus
S/E 5HT3 antagonist
Constipation, headache, Long QT syndrome, parkinsonism
S/E D2 antagonists
Galactorrhoea, dystonia and parkinsonism.
Other use for domperidone
Increase lactation in breastfeeding mothers
Agents acting on CTZ
D2 receptor antagonists, corticosteroids, cannabinoids, neurokinin 1 receptor antagonists
D2 antagonist working on CTZ
Haloperidol
Corticosteroids
Dexamethasone
S/E corticosteroids
Insomnia, increased BM and appetite
Nabilone
Cannabinoids- last line treatment
Aprepitant
Neurokinin 1 receptor antagonist, prevents action of substance P at CTZ and peripheral nerves. Boost effects of 5HT3 receptor antagonist.
Domperidone, metoclopramide
Prokinetic. GORD, Ileus
Risk of prokinetic
Obstruction and risk of perforation
Treat hyperemesis gtavidarum
Promethazine or Prochlorperazine (H1 and D2 antag)
Risk for post op nausea
Female, non smoker, young, laparoscopic
Loperamide, codeine, morphine
Opioid receptor agonist, decreases tone of long and circu smooth muscle. Reduces peristalsis, increases segmental contractions
S/E opioid receptor agonist
Paralytic ileus, n and v, sedation and addiction
Constipating diet
Bananas, white bread, white rice
Lactulose and movicol
Osmotic laxative. Lactulose draws in and macrogols retain fluid they came with
Senna
Stimulant laxative- increase intestinal motility.
Docusate sodium
Stool softeners, decrease surface tension of stool. Increase penetration of fluid in stool.
