Session 12 and podcasts Flashcards
(21 cards)
What receptors are present on the basolateral membrane of parietal cells?
Cholecystokinin, Ach and histamine (H2 type)
Describe the normal control of gastric motility
Myogenic - rhythmic contractions, interstitial cells of cajal act as pacemakers
Neural - post ganglionic cholinergic enteric nerves increase force of contraction, non-adrenergic inhibitory nerves inhibits contraction
Hormonal - e.g. gastrim, CCK, secretin, histamine, prostaglandins
What are the different classifications of anti-emetics? Give examples
Dopamine (D2) receptor antagonists - domperidone, metoclopramide
Serotonin receptor antagonists - ondansetron
Anti muscarinics - hyoscine
Histamine (H1) receptor antagonists - cyclizine
Where is the chemoreceptor trigger zone found?
Postrema At the floor of the 4th ventricle
What are the different classifications of laxatives? Give examples
Non pharmacological - treat cause (diabetes, cancer, parkinsons, dehydration), increase fluids, high fibre, exercise
Bulk - I
Faecal softeners - glycerol, arachis oil (enema)
Osmotic - lactulose, macrogols, phoshate enema
Irritants/stimulants (if soft faeces) - castor oil, senna
List some common drugs that can cause constipation
Anti cholinergics, antidepressants, antiepileptics, antipsychotics, indapamide, opioids, verapamil, iron
How do bulk laxatives work and when are they contraindicated?
Increase faecal mass, which stimulates peristalsis.
They must be taken with plenty of fluid
Contra-indications: dysphagia; intestinal obstruction; faecal impaction. Cause flatulence. Same as faecal softeners
What are possible side effects of faecal softeners?
Anal seepage, malabsorption of fat-soluble vitamins
How does a phosphate enema work?
Mg and Na salts cause water retention in bowel to increase peristalsis. Usually PR. For rapid evacuation
How do irritant/stimulant laxatives work?
Excitation of sensory nerve endings leads to water and electrolyte retention. Used for rapid treatment. Repeated use can cause colonic atony and hypokalaemia
What are the classifications or drugs used to treat diarrhoea? (the symptoms not the cause) and examples
Anti motility - codeine, loperamide (imodium)
Bulk forming - water absorption. Useful for IBS/ileostomy
Fluid adsorbents
What two drugs can be combined in the treatment of IBS?
Mebeverline and bulk forming agent
List some drugs that can cause diarrhoea
Antibiotics, Chemotherapy, Lansoprazole, Iron preparations, SSRI, NSAIDs
What are the different types of ADRs?
A - exaggerated pharmacological response, predictable, dose dependent, common
B - not expected from known pharmacology, dose independent, higher mortality
What is reported to the yellow card scheme and what is this scheme for?
All suspected ADRs of recently introduced products
All reactions to vaccines
Serious or unusual reactions of established products
Generates new ADR hypothesis for a cohort study
What are risk factors for drug inefficacy or toxicity?
Drug-drug interactions, age, renal and liver function, smaking and alcohol consumption, genetic variability
Describe the metabolic action of glucocorticoids
(Think cortisol) stimulates glycogenolysis, gluconeogenesis, hyperglycaemia, proteinolysis, lipolysis
Describe the relative gucocorticoid and mineralocorticoid actions of different corticosteroids and compare their anti inflammatory effects
Hydrocortisone - 1:1. 4 times less anti-inflammatory than prednisolone
Prednisolone - more GC 4:0.8
Dexmethasone - more GC 25:0. More anti inflammatory
Fludrocortisone - more MC 125:10
What are corticosteroid effects on the immune system?
Inhibiton of B/T cell responses, Reduced transcription of cytokines and cell adhesion molecules. Reduced phagocytic function.
What are clinical uses or steroid drugs?
Inflammatory disease - asthma, GI disease, inflammatory skin conditions, nephrotic syndrome, vasculitis/sarcoiditis/RA
Immunosuppression
Malignancy
Adrenal insufficiency - hydrocortisone/fludrocortisone
Cushing’s diagnosis
What are side effects of steroid drugs?
Mineralocorticoid - fluid retention, hypertension, hypokalaemia
Glucocorticoid - osteoporosis, avascular necrosis, peptic ulcers, more infections, hypertension, diabetes, impaired growth, cataracts, cushingoid features
