Drugs - GI Flashcards
Alumium hydroxide
Antacid (Neutraliser) – Alkaline
Alkaline neutralises stomach acids
Uses: relieving symptoms of heartburn (GORD) or peptic ulcers
ADRs: constipation, osteoporosis (long term)
Gaviscon (raft/compound alginate)
Raft antacid
Floats on stomach contents preventing reflux of acid
Relieves GERD
Hyoscine
Antispasmodic – antimuscarinic
Competitive antagonist at muscarinic receptors
Uses: motion sickness + post op nausea
ADRs: dry mouth, tachycardia, bradycardia, itching
Mebeverine
Antispasmodic
Antimuscarinic
Also inhibitor of calcium deposition in cells, reducing contractile force and relieving gut spasms
Uses: IBS and IBS with diverticulosis, diverticulisis, peptic ulcers, inflammation
Ranitidine
H2 antagonist
Anti – H2 receptor
Competitive inhibitor of histamine in gastric parietal cells. Reduces parietal cell acid production
Uses: heartburn, peptic ulcer maintenance, GORD, Erosive oesophagitis, H. pylori eradication (part of regime), Upper GI bleeds
ADRs: headaches, bradycardia, pneumonia, increased risk of clostridium difficile, B12 deficiency
Omeprazole
PPI
Inhibits H+/K+ ATPase on gastric parietal cells
Uses: GORD, Peptyic ulcers, erosive oesophagitis, H.pylori (as part of regime)
ADRs: headache, URTI, abdo pain, constipation
Esomeprazole
PPI
Inhibits H+/K+ ATPase on gastric parietal cells
Uses: GORD, Peptyic ulcers, H.pylori (as part of regime)
ADRs: dry mouth,, insomnia, drowsiness, itching
Loperamide (Imodium)
Anti-motility
Opioid receptor agonist for mu opiod receptors in myenteric plexus, decreasing activity and hence tone of gut wall smooth muscle, decreases colonic mass movement
Uses: Diarrhoea (travelers, IBS, bowel resection) and useful for reducing ileostomy output
Should be avoided in presence of high fever (rebound constipation), hepatic impairment (reduced first pass) and if infection that can penetrate gut wall is present (E.g. e. coli, salmonella or c. diff)
ADRs: In c. diff infection can cause toxic retention/megacolon
Lactulose
Hyper-osmotic Laxative
Osmotic retention of water in GI tract due to non-absorption
Uses: constipation or hepatic encephalopathy
ADRs: bloating and cramps, potential electrolyte problems
Senna
Stimulant laxative
Breakdown of senna produces irritation of gastric mucosa and hypersecretion + colonic motility
Uses: constipation
ADRs: abdo cramps and electrolyte problems
Mesalazine
Anti-inflammatory (Amino-salicylate)
Hypothesised COX inhibitor, reducing gut inflammation
Uses: UC and mild-moderate Crohns
ADRs: diarrhoea, nausea, cramping, flatulence
Infliximab
Monoclonal antibody
Anti-TNF-alpha (prevents it binding to cells)
Uses: autoimmune diseases such as Crohns, UC, Psoriasis, Rheumatoid arthritis
ADRs: immunosuppression (serious infections, reactivation of Hep B/TB, Lupus, Psoriasis)
