GI Flashcards
Which class of drugs induce GI bleeding?
NSAIDs
An overdose of what drug causes acute liver cell necrosis?
Paracetamol
Common drugs causing constipation:
Codeine
Antidepressants
Phenytoin damages which organ ?
Liver
Tetracyclines damage which organ ?
Liver
Amiodarone damages which organ ?
Liver
Name 4 drugs which are known to increase GOR
- Anticholinergics (e.g. Ipratropium bromide)
- Calcium channel blockers (e.g. Diltiazem)
- Theophylline (COPD)
- Nitrates
Name 3 types of drugs that can induce vomiting:
- Opiates (e.g. Codeine)
- Dopamine agonist
- Cytotoxics
Which class of antibiotic can cause oesophageal irritation and dysphagia ?
Tetracyclines e.g. Doxycycline
What drug class is Gaviscon ?
Antacid
How does Gaviscon work?
Neutralises stomach acid, for,s raft over stomach contents to reduce reflux and protects oesophageal mucosa from regurgitation
Contraindication of Gaviscon ?
Renal impairment (mg salts) Hypophosphataemia
Possible interactions of Gaviscon ?
- Decrease absorption of: ACE inhibitors, antibacterials, digoxin, iron
- increases excretion of lithium
- damages enteric coated tablets causing early induction
What class of drug is ranitidine ? How does it work ?
H2 antagonist - competitively inhibits histamine actions at all H2 receptors (inc. parietal cells), therefore inhibits histamine-stimulated gastric acid secretions -> reduction in gastric acid secretion
Indications for Gaviscon ?
- mild symptoms of GORD
- erosive oesophagitis heartburn
- gastric/duodenal ulcers
Indications for ranitidine
- benign gastric/duodenal ulcers
- chronic episodic dyspepsia
- GORD
Side effects of ranitidine
- diarrhoea
- GI/LFT disturbances
- headache/dizziness/fatigue
- rash
Possible interactions of cimetidine ?
Increased concentrations of anticoagulants, phenytoin, carbamazepine, quinidine, nifedipine, theophylline
(Acts on cyp450)
What class of drug is omeprazole ? How does it work ?
PPI
- works by blocking hydrogen/potassium pump ATPase enzyme in parietal cells, inhibiting the proton pump and therefore inhibiting acid secretion
Indications for PPIs
- GORD
- dyspepsia
- oesophagitis
- gastric/duodenal ulcers
- H. Pylori eradication
Contraindications of PPIs
- liver disease
- breast feeding/ pregnancy
Side effects of PPIs
- GI disturbances
- headache
- rarely: dry mouth, peripheral oedema, pruritis
Interactions of PPIs
Acts on cyp450 so increases concentrations of phenytoin, warfarin etc
How are PPIs eliminated ?
80% renal
20% faecal
What class of drug s loperamide, how does it work ?
Anti-diarrhoeal
- acts on opioid receptors in mesenteric plexus inhibiting Ach release - inhibits peristalsis
Indications for loperamide ?
Acute diarrhoea Chronic diarrhoea (adults only)
Contraindications of loperamide
- active ulcerative colitis
- antibiotic associated colitis
- dysentery
Side effects of loperamide ?
- abdo cramps
- dizziness/Fatigue
- skin reactions
Possible interactions of loperamide
Desmopressin
What class of drug is Senna? How does it work ?
Laxative
- hydrolysed in colon to produce glycoside derivatives
- these directly stimulate the mesenteric plexus causing increased smooth muscle contraction
What class of drug is mesalazine ? How does it work ?
Amino salicylate
- releases 5-ASA into bowel which acts as an anti-inflammatory
Indications for mesalazine ?
Mild- moderate UC
Contraindications of mesalazine?
Renal impairment
