P15 Flashcards
Allopurinol
Xanthine oxidase inhibitor
Use:
- Prevent gout and renal calculi due to uric acid or calcium oxalate
- Treat uric acid neuropathy
- Treat hyperuricemia
- Treat some solid tumours
Chlorpromazine
Dopamine receptor antagonist
Use:
- Psychotropic agent
- Sedative
- Antiemetic
Loperamide
Opiate receptor agonist + non-selective calcium channel blocker
MoA:
- Binds to opioid mu-receptors in the myenteric plexus large intestine
- Can’t cross BBB so doesn’t act in brain
Use:
- Antidiarrhoeal agent
- Decreases activity of myenteric plexus
- Decreases colonic mass movement, suppresses gastrocolic reflex, increases water absorption from faecal matter, increases amount of time substances stay in the intestine.
Kaolin
Absorptive agent
Use:
- Antidiarrhoeal agent
- Absorbs: water, toxins, bacteria leading to firmer stools and less fluid loss
- Also used to treat AIDS-related diarrhoea
Lactulose
Osmotic laxative
MoA:
- In the colon, lactulose is broken down primarily to lactic acid, via colonic bacteria.
- This results in an increase in osmotic pressure causing an increase in stool water content softening the stool.
Use:
- Laxative
- Lactulose is a synthetic sugar (fructose and galactose) used in the treatment of constipation.
Octreotide
Somatostatin receptor agonist
MoA:
- It leads to adenyl cyclase inhibition via pertussis toxin sensitive G proteins and both stimulation of phosphotyrosine phosphatase and activation of the Na+/H+ exchanger via pertussis toxin insensitive G proteins.
Use:
- Antidiarrhoeal agent
- Treatment of diarrhoea associated with metastatic carcinoid tumours and vasoactive intestinal peptide secreting adenomas
Bisacodyl
Stimulant laxative
MoA:
- Bisacodyl is hydrolysed by intestinal brush border enzymes and colonic bacteria to form an active metabolite that acts directly on the colonic mucosa to produce colonic peristalsis.
Use:
- Laxative
- To clean colon prior to colonoscopy and for enema as rectal suppository
Docusate sodium
Stimulant/detergent laxative
MoA:
- The effects of docusate may arise from the direct laxative effects of the molecule on the intestinal mucosa.
- Or the indirect action of local endogenous prostaglandins released from the intestine upon contact with docusate.
Use:
- Laxative
- Used to help prevent straining to have a bowel movement in patients who have just had a heart attack or surgery.
Hydrocortisone
Glucocorticoid receptor agonist
MoA:
- After binding the receptor the newly formed receptor-ligand complex translocates itself into the cell nucleus, where it binds to many glucocorticoid response elements (GRE) in the promoter region of the target genes.
- The DNA bound receptor then interacts with basic transcription factors, causing the increase in expression of specific target genes.
Use:
- Topical hydrocortisone used for its anti-inflammatory or immunosuppressive properties to treat inflammation due to corticosteroid-responsive dermatoses.
- Treatment of inflammation, allergy, collagen diseases, asthma, adrenocortical deficiency, shock, and some neoplastic conditions.
Betamethasone
Glucocorticoid receptor agonist.
MoA:
- Leads to changes in genetic expression once this complex binds to the GRE.
- The antiinflammatory actions of corticosteroids are thought to involve lipocortins, phospholipase A2 inhibitory proteins which, through inhibition arachidonic acid, control the biosynthesis of prostaglandins and leukotrienes.
Use:
- Rheumatoid arthritis
- Lupus
- Dermatitis and psoriasis
- Asthma and angioedema
- Crohn’s disease
- Cancers such as leukemia, and along with fludrocortisone for adrenocortical insufficiency
Beclomethasone
Glucocorticoid receptor agonist.
MoA:
- Unbound corticosteroids cross cell membranes and bind with high affinity to specific cytoplasmic receptors. - The result includes inhibition of leukocyte infiltration at the site of inflammation, interference in the function of mediators of inflammatory response, suppression of humoral immune responses, and reduction in oedema or scar tissue.
Use:
- Treating steroid-dependent asthma, allergic or nonallergic rhinitis, or recurrent nasal polyps.
Fludrocortisone
Mineralocorticoid nuclear hormone receptor agonist
MoA:
- Binding (or activation of the mineralocorticoid receptor by fludrocortisone) causes an increase in ion and water transport and thus raises extracellular fluid volume and blood pressure and lowers potassium levels.
Use:
- Treat conditions in which the body does not produce enough of its own steroids
- E.g. Addison’s disease, and salt-losing adrenogenital syndrome.
